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diff --git a/slib_7.html b/slib_7.html deleted file mode 100644 index 932a042..0000000 --- a/slib_7.html +++ /dev/null @@ -1,8218 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" - "http://www.w3.org/TR/html40/loose.dtd"> -<HTML> -<!-- Created on January, 10 2005 by texi2html 1.66 --> -<!-- -Written by: Lionel Cons <Lionel.Cons@cern.ch> (original author) - Karl Berry <karl@freefriends.org> - Olaf Bachmann <obachman@mathematik.uni-kl.de> - and many others. -Maintained by: Many creative people <dev@texi2html.cvshome.org> -Send bugs and suggestions to <users@texi2html.cvshome.org> - ---> -<HEAD> -<TITLE>SLIB: Other Packages</TITLE> - -<META NAME="description" CONTENT="SLIB: Other Packages"> -<META NAME="keywords" CONTENT="SLIB: Other Packages"> -<META NAME="resource-type" CONTENT="document"> -<META NAME="distribution" CONTENT="global"> -<META NAME="Generator" CONTENT="texi2html 1.66"> - -</HEAD> - -<BODY LANG="en" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#800080" ALINK="#FF0000"> - -<A NAME="SEC183"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_6.html#SEC182"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_6.html#SEC140"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H1> 7. Other Packages </H1> -<!--docid::SEC183::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC184">7.1 Data Structures</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Various data structures.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC207">7.2 Sorting and Searching</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC225">7.3 Procedures</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Miscellaneous utility procedures.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC235">7.4 Standards Support</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Support for Scheme Standards.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC263">7.5 Session Support</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">REPL and Debugging.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC269">7.6 System Interface</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'system, 'getenv, and other programs.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC276">7.7 Extra-SLIB Packages</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Outside the envelope.</TD></TR> -</TABLE> -<P> - -<A NAME="Data Structures"></A> -<HR SIZE="6"> -<A NAME="SEC184"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC185"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.1 Data Structures </H2> -<!--docid::SEC184::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC185">7.1.1 Arrays</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'array</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC186">7.1.2 Subarrays</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'subarray</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC187">7.1.3 Array Mapping</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'array-for-each</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC188">7.1.4 Association Lists</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'alist</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC189">7.1.5 Byte</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'byte</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC190">7.1.6 Byte/Number Conversions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'byte-number</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC192">7.1.7 MAT-File Format</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'matfile</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC193">7.1.8 Portable Image Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'pnm</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC194">7.1.9 Collections</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'collect</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC195">7.1.10 Dynamic Data Type</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'dynamic</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC196">7.1.11 Hash Tables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'hash-table</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC197">7.1.12 Macroless Object System</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'object</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC204">7.1.16 Priority Queues</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'priority-queue</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC205">7.1.17 Queues</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'queue</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC206">7.1.18 Records</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'record</TD></TR> -</TABLE> -<P> - -<A NAME="Arrays"></A> -<HR SIZE="6"> -<A NAME="SEC185"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC186"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.1 Arrays </H3> -<!--docid::SEC185::--> -<P> - -<CODE>(require 'array)</CODE> -<A NAME="IDX1094"></A> -</P> -<P> - -<A NAME="IDX1095"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array?</B> <I>obj</I> -<DD><P> - -Returns <CODE>#t</CODE> if the <VAR>obj</VAR> is an array, and <CODE>#f</CODE> if not. -</P> -</DL> -<EM>Note:</EM> Arrays are not disjoint from other Scheme types. Strings -and vectors also satisfy <CODE>array?</CODE>. A disjoint array predicate can -be written: -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define (strict-array? obj) - (and (array? obj) (not (string? obj)) (not (vector? obj)))) -</pre></td></tr></table><P> - -<A NAME="IDX1096"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array=?</B> <I>array1 array2</I> -<DD><P> - -Returns <CODE>#t</CODE> if <VAR>array1</VAR> and <VAR>array2</VAR> have the same rank and shape and the -corresponding elements of <VAR>array1</VAR> and <VAR>array2</VAR> are <CODE>equal?</CODE>. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(array=? (create-array '#(foo) 3 3) - (create-array '#(foo) '(0 2) '(0 2))) - => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1097"></A> -</P> -<DL> -<DT><U>Function:</U> <B>create-array</B> <I>prototype bound1 bound2 <small>...</small></I> -<DD><P> - -Creates and returns an array of type <VAR>prototype</VAR> with dimensions <VAR>bound1</VAR>, <VAR>bound2</VAR>, -<small>...</small> and filled with elements from <VAR>prototype</VAR>. <VAR>prototype</VAR> must be an array, -vector, or string. The implementation-dependent type of the returned -array will be the same as the type of <VAR>prototype</VAR>; except if that would be a -vector or string with non-zero origin, in which case some variety of -array will be returned. -</P> -<P> - -If the <VAR>prototype</VAR> has no elements, then the initial contents of the returned -array are unspecified. Otherwise, the returned array will be filled -with the element at the origin of <VAR>prototype</VAR>. -</P> -</DL> -These functions return a prototypical uniform-array enclosing the -optional argument (which must be of the correct type). If the -uniform-array type is supported by the implementation, then it is -returned; defaulting to the next larger precision type; resorting -finally to vector. -<P> - -<A NAME="IDX1098"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ac64</B> <I>z</I> -<DD><P> - -<A NAME="IDX1099"></A> -<DT><U>Function:</U> <B>ac64</B> -<DD>Returns a high-precision complex uniform-array prototype. -</P> -</DL> -<P> - -<A NAME="IDX1100"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ac32</B> <I>z</I> -<DD><P> - -<A NAME="IDX1101"></A> -<DT><U>Function:</U> <B>ac32</B> -<DD>Returns a complex uniform-array prototype. -</P> -</DL> -<P> - -<A NAME="IDX1102"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ar64</B> <I>x</I> -<DD><P> - -<A NAME="IDX1103"></A> -<DT><U>Function:</U> <B>ar64</B> -<DD>Returns a high-precision real uniform-array prototype. -</P> -</DL> -<P> - -<A NAME="IDX1104"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ar32</B> <I>x</I> -<DD><P> - -<A NAME="IDX1105"></A> -<DT><U>Function:</U> <B>ar32</B> -<DD>Returns a real uniform-array prototype. -</P> -</DL> -<P> - -<A NAME="IDX1106"></A> -</P> -<DL> -<DT><U>Function:</U> <B>as64</B> <I>n</I> -<DD><P> - -<A NAME="IDX1107"></A> -<DT><U>Function:</U> <B>as64</B> -<DD>Returns an exact signed integer uniform-array prototype with at least -64 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1108"></A> -</P> -<DL> -<DT><U>Function:</U> <B>as32</B> <I>n</I> -<DD><P> - -<A NAME="IDX1109"></A> -<DT><U>Function:</U> <B>as32</B> -<DD>Returns an exact signed integer uniform-array prototype with at least -32 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1110"></A> -</P> -<DL> -<DT><U>Function:</U> <B>as16</B> <I>n</I> -<DD><P> - -<A NAME="IDX1111"></A> -<DT><U>Function:</U> <B>as16</B> -<DD>Returns an exact signed integer uniform-array prototype with at least -16 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1112"></A> -</P> -<DL> -<DT><U>Function:</U> <B>as8</B> <I>n</I> -<DD><P> - -<A NAME="IDX1113"></A> -<DT><U>Function:</U> <B>as8</B> -<DD>Returns an exact signed integer uniform-array prototype with at least -8 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1114"></A> -</P> -<DL> -<DT><U>Function:</U> <B>au64</B> <I>k</I> -<DD><P> - -<A NAME="IDX1115"></A> -<DT><U>Function:</U> <B>au64</B> -<DD>Returns an exact non-negative integer uniform-array prototype with at -least 64 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1116"></A> -</P> -<DL> -<DT><U>Function:</U> <B>au32</B> <I>k</I> -<DD><P> - -<A NAME="IDX1117"></A> -<DT><U>Function:</U> <B>au32</B> -<DD>Returns an exact non-negative integer uniform-array prototype with at -least 32 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1118"></A> -</P> -<DL> -<DT><U>Function:</U> <B>au16</B> <I>k</I> -<DD><P> - -<A NAME="IDX1119"></A> -<DT><U>Function:</U> <B>au16</B> -<DD>Returns an exact non-negative integer uniform-array prototype with at -least 16 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1120"></A> -</P> -<DL> -<DT><U>Function:</U> <B>au8</B> <I>k</I> -<DD><P> - -<A NAME="IDX1121"></A> -<DT><U>Function:</U> <B>au8</B> -<DD>Returns an exact non-negative integer uniform-array prototype with at -least 8 bits of precision. -</P> -</DL> -<P> - -<A NAME="IDX1122"></A> -</P> -<DL> -<DT><U>Function:</U> <B>at1</B> <I>bool</I> -<DD><P> - -<A NAME="IDX1123"></A> -<DT><U>Function:</U> <B>at1</B> -<DD>Returns a boolean uniform-array prototype. -</P> -</DL> -When constructing an array, <VAR>bound</VAR> is either an inclusive range of -indices expressed as a two element list, or an upper bound expressed as -a single integer. So -<P> - -<TABLE><tr><td> </td><td class=example><pre>(create-array '#(foo) 3 3) == (create-array '#(foo) '(0 2) '(0 2)) -</pre></td></tr></table><P> - -<A NAME="IDX1124"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-shared-array</B> <I>array mapper bound1 bound2 <small>...</small></I> -<DD><P> - -<CODE>make-shared-array</CODE> can be used to create shared subarrays of other -arrays. The <VAR>mapper</VAR> is a function that translates coordinates in -the new array into coordinates in the old array. A <VAR>mapper</VAR> must be -linear, and its range must stay within the bounds of the old array, but -it can be otherwise arbitrary. A simple example: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define fred (create-array '#(#f) 8 8)) -(define freds-diagonal - (make-shared-array fred (lambda (i) (list i i)) 8)) -(array-set! freds-diagonal 'foo 3) -(array-ref fred 3 3) - => FOO -(define freds-center - (make-shared-array fred (lambda (i j) (list (+ 3 i) (+ 3 j))) - 2 2)) -(array-ref freds-center 0 0) - => FOO -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1125"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-rank</B> <I>obj</I> -<DD><P> - -Returns the number of dimensions of <VAR>obj</VAR>. If <VAR>obj</VAR> is not an array, 0 is -returned. -</P> -</DL> -<P> - -<A NAME="IDX1126"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-shape</B> <I>array</I> -<DD><P> - -Returns a list of inclusive bounds. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(array-shape (create-array '#() 3 5)) - => ((0 2) (0 4)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1127"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-dimensions</B> <I>array</I> -<DD><P> - -<CODE>array-dimensions</CODE> is similar to <CODE>array-shape</CODE> but replaces -elements with a 0 minimum with one greater than the maximum. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(array-dimensions (create-array '#() 3 5)) - => (3 5) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1128"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-in-bounds?</B> <I>array index1 index2 <small>...</small></I> -<DD><P> - -Returns <CODE>#t</CODE> if its arguments would be acceptable to -<CODE>array-ref</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1129"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-ref</B> <I>array index1 index2 <small>...</small></I> -<DD><P> - -Returns the (<VAR>index1</VAR>, <VAR>index2</VAR>, <small>...</small>) element of <VAR>array</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1130"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>array-set!</B> <I>array obj index1 index2 <small>...</small></I> -<DD><P> - -Stores <VAR>obj</VAR> in the (<VAR>index1</VAR>, <VAR>index2</VAR>, <small>...</small>) element of <VAR>array</VAR>. The value returned -by <CODE>array-set!</CODE> is unspecified. -</P> -</DL> -<P> - -<A NAME="Subarrays"></A> -<HR SIZE="6"> -<A NAME="SEC186"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC185"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC187"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.2 Subarrays </H3> -<!--docid::SEC186::--> -<P> - -<CODE>(require 'subarray)</CODE> -<A NAME="IDX1131"></A> -</P> -<P> - -<A NAME="IDX1132"></A> -</P> -<DL> -<DT><U>Function:</U> <B>subarray</B> <I>array select <small>...</small></I> -<DD><P> - -selects a subset of an array. For <VAR>array</VAR> of rank n, there must be at least -n <VAR>selects</VAR> arguments. For 0 <= <I>j</I> < n, <VAR>selects</VAR><I>j</I> is either an integer, a -list of two integers within the range for the <I>j</I>th index, or #f. -</P> -<P> - -When <VAR>selects</VAR><I>j</I> is a list of two integers, then the <I>j</I>th index is -restricted to that subrange in the returned array. -</P> -<P> - -When <VAR>selects</VAR><I>j</I> is #f, then the full range of the <I>j</I>th index is -accessible in the returned array. An elided argument is equivalent to #f. -</P> -<P> - -When <VAR>selects</VAR><I>j</I> is an integer, then the rank of the returned array is -less than <VAR>array</VAR>, and only elements whose <I>j</I>th index equals <VAR>selects</VAR><I>j</I> are -shared. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>> (define ra '#2A((a b c) (d e f))) -#<unspecified> -> (subarray ra 0 #f) -#1A(a b c) -> (subarray ra 1 #f) -#1A(d e f) -> (subarray ra #f 1) -#1A(b e) -> (subarray ra '(0 1) #f) -#2A((a b c) (d e f)) -> (subarray ra #f '(0 1)) -#2A((a b) (d e)) -> (subarray ra #f '(1 2)) -#2A((b c) (e f)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1133"></A> -</P> -<DL> -<DT><U>Function:</U> <B>subarray0</B> <I>array select <small>...</small></I> -<DD><P> - -Behaves like subarray, but aligns the returned array origin to -0 <small>...</small>. -</P> -</DL> -<P> - -<A NAME="IDX1134"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-align</B> <I>array coord <small>...</small></I> -<DD><P> - -Returns an array shared with <VAR>array</VAR> but with a different origin. The <VAR>coords</VAR> -are the exact integer coordinates of the new origin. Indexes -corresponding to missing or #f coordinates are not realigned. -</P> -<P> - -For example: -<TABLE><tr><td> </td><td class=example><pre>(define ra2 (create-array '#(5) '(5 9) '(-4 0))) -(array-shape ra2) => ((5 9) (-4 0)) -(array-shape (array-align ra2 0 0)) => ((0 4) (0 4)) -(array-shape (array-align ra2 0)) => ((0 4) (-4 0)) -(array-shape (array-align ra2)) => ((5 9) (-4 0)) -(array-shape (array-align ra2 0 #f)) => ((0 4) (-4 0)) -(array-shape (array-align ra2 #f 0)) => ((5 9) (0 4)) -</pre></td></tr></table></DL> - -<A NAME="IDX1135"></A> -<DL> -<DT><U>Function:</U> <B>array-trim</B> <I>array trim <small>...</small></I> -<DD><P> - -Returns a subarray sharing contents with <VAR>array</VAR> except for slices removed -from either side of each dimension. Each of the <VAR>trims</VAR> is an exact -integer indicating how much to trim. A positive <VAR>s</VAR> trims the -data from the lower end and reduces the upper bound of the result; a -negative <VAR>s</VAR> trims from the upper end and increases the lower -bound. -</P> -<P> - -For example: -<TABLE><tr><td> </td><td class=example><pre>(array-trim '#(0 1 2 3 4) 1) => #1A(1 2 3 4) ;; shape is ((0 3)) -(array-trim '#(0 1 2 3 4) -1) => #1A(0 1 2 3) ;; shape is ((1 4)) - -(require 'array-for-each) -(define (centered-difference ra) - (array-map - (array-trim ra 1) (array-trim ra -1))) -(define (forward-difference ra) - (array-map - (array-trim ra 1) ra)) -(define (backward-difference ra) - (array-map - ra (array-trim ra -1))) - -(centered-difference '#(0 1 3 5 9 22)) - => #1A(3 4 6 17) ;;shape is ((1 4)) -(backward-difference '#(0 1 3 5 9 22)) - => #1A(1 2 2 4 13) ;; shape is ((1 5)) -(forward-difference '#(0 1 3 5 9 22)) - => #(1 2 2 4 13) ;; shape is ((0 4)) -</pre></td></tr></table></DL> -<P> - -<A NAME="Array Mapping"></A> -<HR SIZE="6"> -<A NAME="SEC187"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC186"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC188"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.3 Array Mapping </H3> -<!--docid::SEC187::--> -<P> - -<CODE>(require 'array-for-each)</CODE> -<A NAME="IDX1136"></A> -</P> -<P> - -<A NAME="IDX1137"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>array-map!</B> <I>array0 proc array1 <small>...</small></I> -<DD><P> - -<VAR>array1</VAR>, <small>...</small> must have the same number of dimensions as -<VAR>array0</VAR> and have a range for each index which includes the range -for the corresponding index in <VAR>array0</VAR>. <VAR>proc</VAR> is applied to -each tuple of elements of <VAR>array1</VAR> <small>...</small> and the result is stored -as the corresponding element in <VAR>array0</VAR>. The value returned is -unspecified. The order of application is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1138"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-map</B> <I>prototype proc array1 array2 <small>...</small></I> -<DD><P> - -<VAR>array2</VAR>, <small>...</small> must have the same number of dimensions as -<VAR>array1</VAR> and have a range for each index which includes the -range for the corresponding index in <VAR>array1</VAR>. <VAR>proc</VAR> is -applied to each tuple of elements of <VAR>array1</VAR>, <VAR>array2</VAR>, -<small>...</small> and the result is stored as the corresponding element in a -new array of type <VAR>prototype</VAR>. The new array is returned. The -order of application is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1139"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-for-each</B> <I>proc array0 <small>...</small></I> -<DD><P> - -<VAR>proc</VAR> is applied to each tuple of elements of <VAR>array0</VAR> <small>...</small> -in row-major order. The value returned is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1140"></A> -</P> -<DL> -<DT><U>Function:</U> <B>array-indexes</B> <I>array</I> -<DD><P> - -Returns an array of lists of indexes for <VAR>array</VAR> such that, if -<VAR>li</VAR> is a list of indexes for which <VAR>array</VAR> is defined, -(equal? <VAR>li</VAR> (apply array-ref (array-indexes <VAR>array</VAR>) -<VAR>li</VAR>)). -</P> -</DL> -<P> - -<A NAME="IDX1141"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>array-index-map!</B> <I>array proc</I> -<DD><P> - -applies <VAR>proc</VAR> to the indices of each element of <VAR>array</VAR> in -turn, storing the result in the corresponding element. The value -returned and the order of application are unspecified. -</P> -<P> - -One can implement <VAR>array-indexes</VAR> as -<TABLE><tr><td> </td><td class=example><pre>(define (array-indexes array) - (let ((ra (apply create-array '#() (array-shape array)))) - (array-index-map! ra (lambda x x)) - ra)) -</pre></td></tr></table>Another example: -<TABLE><tr><td> </td><td class=example><pre>(define (apl:index-generator n) - (let ((v (make-vector n 1))) - (array-index-map! v (lambda (i) i)) - v)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1142"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>array-copy!</B> <I>source destination</I> -<DD><P> - -Copies every element from vector or array <VAR>source</VAR> to the -corresponding element of <VAR>destination</VAR>. <VAR>destination</VAR> must -have the same rank as <VAR>source</VAR>, and be at least as large in each -dimension. The order of copying is unspecified. -</P> -</DL> -<P> - -<A NAME="Association Lists"></A> -<HR SIZE="6"> -<A NAME="SEC188"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC187"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC189"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.4 Association Lists </H3> -<!--docid::SEC188::--> -<P> - -<CODE>(require 'alist)</CODE> -<A NAME="IDX1143"></A> -</P> -<P> - -Alist functions provide utilities for treating a list of key-value pairs -as an associative database. These functions take an equality predicate, -<VAR>pred</VAR>, as an argument. This predicate should be repeatable, -symmetric, and transitive. -</P> -<P> - -Alist functions can be used with a secondary index method such as hash -tables for improved performance. -</P> -<P> - -<A NAME="IDX1144"></A> -</P> -<DL> -<DT><U>Function:</U> <B>predicate->asso</B> <I>pred</I> -<DD><P> - -Returns an <EM>association function</EM> (like <CODE>assq</CODE>, <CODE>assv</CODE>, or -<A NAME="IDX1145"></A> -<CODE>assoc</CODE>) corresponding to <VAR>pred</VAR>. The returned function -returns a key-value pair whose key is <CODE>pred</CODE>-equal to its first -argument or <CODE>#f</CODE> if no key in the alist is <VAR>pred</VAR>-equal to the -first argument. -</P> -</DL> -<P> - -<A NAME="IDX1146"></A> -</P> -<DL> -<DT><U>Function:</U> <B>alist-inquirer</B> <I>pred</I> -<DD><P> - -Returns a procedure of 2 arguments, <VAR>alist</VAR> and <VAR>key</VAR>, which -returns the value associated with <VAR>key</VAR> in <VAR>alist</VAR> or <CODE>#f</CODE> if -<VAR>key</VAR> does not appear in <VAR>alist</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1147"></A> -</P> -<DL> -<DT><U>Function:</U> <B>alist-associator</B> <I>pred</I> -<DD><P> - -Returns a procedure of 3 arguments, <VAR>alist</VAR>, <VAR>key</VAR>, and -<VAR>value</VAR>, which returns an alist with <VAR>key</VAR> and <VAR>value</VAR> -associated. Any previous value associated with <VAR>key</VAR> will be -lost. This returned procedure may or may not have side effects on its -<VAR>alist</VAR> argument. An example of correct usage is: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define put (alist-associator string-ci=?)) -(define alist '()) -(set! alist (put alist "Foo" 9)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1148"></A> -</P> -<DL> -<DT><U>Function:</U> <B>alist-remover</B> <I>pred</I> -<DD><P> - -Returns a procedure of 2 arguments, <VAR>alist</VAR> and <VAR>key</VAR>, which -returns an alist with an association whose <VAR>key</VAR> is key removed. -This returned procedure may or may not have side effects on its -<VAR>alist</VAR> argument. An example of correct usage is: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define rem (alist-remover string-ci=?)) -(set! alist (rem alist "foo")) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1149"></A> -</P> -<DL> -<DT><U>Function:</U> <B>alist-map</B> <I>proc alist</I> -<DD><P> - -Returns a new association list formed by mapping <VAR>proc</VAR> over the -keys and values of <VAR>alist</VAR>. <VAR>proc</VAR> must be a function of 2 -arguments which returns the new value part. -</P> -</DL> -<P> - -<A NAME="IDX1150"></A> -</P> -<DL> -<DT><U>Function:</U> <B>alist-for-each</B> <I>proc alist</I> -<DD><P> - -Applies <VAR>proc</VAR> to each pair of keys and values of <VAR>alist</VAR>. -<VAR>proc</VAR> must be a function of 2 arguments. The returned value is -unspecified. -</P> -</DL> -<P> - -<A NAME="Byte"></A> -<HR SIZE="6"> -<A NAME="SEC189"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC188"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC190"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.5 Byte </H3> -<!--docid::SEC189::--> -<P> - -<CODE>(require 'byte)</CODE> -<A NAME="IDX1151"></A> -</P> -<P> - -Some algorithms are expressed in terms of arrays of small integers. -Using Scheme strings to implement these arrays is not portable vis-a-vis -the correspondence between integers and characters and non-ascii -character sets. These functions abstract the notion of a <EM>byte</EM>. -<A NAME="IDX1152"></A> -<A NAME="IDX1153"></A> -</P> -<P> - -<A NAME="IDX1154"></A> -</P> -<DL> -<DT><U>Function:</U> <B>byte-ref</B> <I>bytes k</I> -<DD><P> - -<VAR>k</VAR> must be a valid index of <VAR>bytes</VAR>. <CODE>byte-ref</CODE> returns byte <VAR>k</VAR> of <VAR>bytes</VAR> using -zero-origin indexing. -</P> -</DL> -<P> - -<A NAME="IDX1155"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>byte-set!</B> <I>bytes k byte</I> -<DD><P> - -<VAR>k</VAR> must be a valid index of <VAR>bytes</VAR>, and <VAR>byte</VAR> must be a small -nonnegative integer. <CODE>byte-set!</CODE> stores <VAR>byte</VAR> in element <VAR>k</VAR> of <VAR>bytes</VAR> and -returns an unspecified value. -</P> -</DL> -<P> - -<A NAME="IDX1156"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-bytes</B> <I>k byte</I> -<DD><P> - -<A NAME="IDX1157"></A> -<DT><U>Function:</U> <B>make-bytes</B> <I>k</I> -<DD><CODE>make-bytes</CODE> returns a newly allocated byte-array of length <VAR>k</VAR>. If <VAR>byte</VAR> is -given, then all elements of the byte-array are initialized to <VAR>byte</VAR>, -otherwise the contents of the byte-array are unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1158"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes-length</B> <I>bytes</I> -<DD><P> - -<CODE>bytes-length</CODE> returns length of byte-array <VAR>bytes</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1159"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes</B> <I>byte <small>...</small></I> -<DD><P> - -Returns a newly allocated byte-array composed of the small -nonnegative arguments. -</P> -</DL> -<P> - -<A NAME="IDX1160"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes->list</B> <I>bytes</I> -<DD><P> - -<CODE>bytes->list</CODE> returns a newly allocated list of the bytes that make up the -given byte-array. -</P> -</DL> -<P> - -<A NAME="IDX1161"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list->bytes</B> <I>bytes</I> -<DD><P> - -<CODE>list->bytes</CODE> returns a newly allocated byte-array formed from the small -nonnegative integers in the list <VAR>bytes</VAR>. -</P> -</DL> -<CODE>Bytes->list</CODE> and <CODE>list->bytes</CODE> are inverses so far as -<CODE>equal?</CODE> is concerned. -<A NAME="IDX1162"></A> -<P> - -<A NAME="IDX1163"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes-copy</B> <I>bytes</I> -<DD><P> - -Returns a newly allocated copy of the given <VAR>bytes</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1164"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>bytes-reverse!</B> <I>bytes</I> -<DD><P> - -Reverses the order of byte-array <VAR>bytes</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1165"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes-reverse</B> <I>bytes</I> -<DD><P> - -Returns a newly allocated bytes-array consisting of the elements of -<VAR>bytes</VAR> in reverse order. -</P> -</DL> -<A NAME="IDX1166"></A> -Input and output of bytes should be with ports opened in <EM>binary</EM> -<A NAME="IDX1167"></A> -mode (see section <A HREF="slib_2.html#SEC16">2.3 Input/Output</A>). Calling <CODE>open-file</CODE> with 'rb or -<A NAME="IDX1168"></A> -'wb modes argument will return a binary port if the Scheme -implementation supports it. -<P> - -<A NAME="IDX1169"></A> -</P> -<DL> -<DT><U>Function:</U> <B>write-byte</B> <I>byte port</I> -<DD><P> - -<A NAME="IDX1170"></A> -<DT><U>Function:</U> <B>write-byte</B> <I>byte</I> -<DD>Writes the byte <VAR>byte</VAR> (not an external representation of the byte) to -the given <VAR>port</VAR> and returns an unspecified value. The <VAR>port</VAR> argument may -be omitted, in which case it defaults to the value returned by -<CODE>current-output-port</CODE>. -<A NAME="IDX1171"></A> -</P> -</DL> -<P> - -<A NAME="IDX1172"></A> -</P> -<DL> -<DT><U>Function:</U> <B>read-byte</B> <I>port</I> -<DD><P> - -<A NAME="IDX1173"></A> -<DT><U>Function:</U> <B>read-byte</B> -<DD>Returns the next byte available from the input <VAR>port</VAR>, updating the <VAR>port</VAR> -to point to the following byte. If no more bytes are available, an -end-of-file object is returned. <VAR>port</VAR> may be omitted, in which case it -defaults to the value returned by <CODE>current-input-port</CODE>. -<A NAME="IDX1174"></A> -</P> -</DL> -When reading and writing binary numbers with <CODE>read-bytes</CODE> and -<CODE>write-bytes</CODE>, the sign of the length argument determines the -endianness (order) of bytes. Positive treats them as big-endian, -the first byte input or output is highest order. Negative treats -them as little-endian, the first byte input or output is the lowest -order. -<P> - -Once read in, SLIB treats byte sequences as big-endian. The -multi-byte sequences produced and used by number conversion routines -see section <A HREF="slib_7.html#SEC190">7.1.6 Byte/Number Conversions</A> are always big-endian. -</P> -<P> - -<A NAME="IDX1175"></A> -</P> -<DL> -<DT><U>Function:</U> <B>read-bytes</B> <I>n port</I> -<DD><P> - -<A NAME="IDX1176"></A> -<DT><U>Function:</U> <B>read-bytes</B> <I>n</I> -<DD><CODE>read-bytes</CODE> returns a newly allocated bytes-array filled with -<CODE>(abs <VAR>n</VAR>)</CODE> bytes read from <VAR>port</VAR>. If <VAR>n</VAR> is positive, then -the first byte read is stored at index 0; otherwise the last byte -read is stored at index 0. Note that the length of the returned -string will be less than <CODE>(abs <VAR>n</VAR>)</CODE> if <VAR>port</VAR> reaches -end-of-file. -</P> -<P> - -<VAR>port</VAR> may be omitted, in which case it defaults to the value returned -by <CODE>current-input-port</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1177"></A> -</P> -<DL> -<DT><U>Function:</U> <B>write-bytes</B> <I>bytes n port</I> -<DD><P> - -<A NAME="IDX1178"></A> -<DT><U>Function:</U> <B>write-bytes</B> <I>bytes n</I> -<DD><CODE>write-bytes</CODE> writes <CODE>(abs <VAR>n</VAR>)</CODE> bytes to output-port <VAR>port</VAR>. If <VAR>n</VAR> is -positive, then the first byte written is index 0 of <VAR>bytes</VAR>; otherwise -the last byte written is index 0 of <VAR>bytes</VAR>. <CODE>write-bytes</CODE> returns an unspecified -value. -</P> -<P> - -<VAR>port</VAR> may be omitted, in which case it defaults to the value returned -by <CODE>current-output-port</CODE>. -</P> -</DL> -<CODE>substring-read!</CODE> and <CODE>substring-write</CODE> provide -lower-level procedures for reading and writing blocks of bytes. The -relative size of <VAR>start</VAR> and <VAR>end</VAR> determines the order of -writing. -<P> - -<A NAME="IDX1179"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>substring-read!</B> <I>string start end port</I> -<DD><P> - -<A NAME="IDX1180"></A> -<DT><U>Procedure:</U> <B>substring-read!</B> <I>string start end</I> -<DD>Fills <VAR>string</VAR> with up to <CODE>(abs (- <VAR>start</VAR> <VAR>end</VAR>))</CODE> bytes -read from <VAR>port</VAR>. The first byte read is stored at index <VAR>string</VAR>. -<CODE>substring-read!</CODE> returns the number of bytes read. -</P> -<P> - -<VAR>port</VAR> may be omitted, in which case it defaults to the value returned -by <CODE>current-input-port</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1181"></A> -</P> -<DL> -<DT><U>Function:</U> <B>substring-write</B> <I>string start end port</I> -<DD><P> - -<A NAME="IDX1182"></A> -<DT><U>Function:</U> <B>substring-write</B> <I>string start end</I> -<DD><CODE>substring-write</CODE> writes <CODE>(abs (- <VAR>start</VAR> <VAR>end</VAR>))</CODE> bytes to -output-port <VAR>port</VAR>. The first byte written is index <VAR>start</VAR> of <VAR>string</VAR>. <CODE>substring-write</CODE> -returns the number of bytes written. -</P> -<P> - -<VAR>port</VAR> may be omitted, in which case it defaults to the value returned -by <CODE>current-output-port</CODE>. -</P> -</DL> -<P> - -<A NAME="Byte/Number Conversions"></A> -<HR SIZE="6"> -<A NAME="SEC190"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC189"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC192"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.6 Byte/Number Conversions </H3> -<!--docid::SEC190::--> -<P> - -<CODE>(require 'byte-number)</CODE> -<A NAME="IDX1183"></A> -</P> -<P> - -The multi-byte sequences produced and used by numeric conversion -routines are always big-endian. Endianness can be changed during -reading and writing bytes using <CODE>read-bytes</CODE> and -<CODE>write-bytes</CODE> See section <A HREF="slib_7.html#SEC189">read-bytes</A>. -</P> -<P> - -The sign of the length argument to bytes/integer conversion -procedures determines the signedness of the number. -</P> -<P> - -<A NAME="IDX1184"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes->integer</B> <I>bytes n</I> -<DD><P> - -Converts the first <CODE>(abs <VAR>n</VAR>)</CODE> bytes of big-endian <VAR>bytes</VAR> array -to an integer. If <VAR>n</VAR> is negative then the integer coded by the -bytes are treated as two's-complement (can be negative). -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(bytes->integer (bytes 0 0 0 15) -4) => 15 -(bytes->integer (bytes 0 0 0 15) 4) => 15 -(bytes->integer (bytes 255 255 255 255) -4) => -1 -(bytes->integer (bytes 255 255 255 255) 4) => 4294967295 -(bytes->integer (bytes 128 0 0 0) -4) => -2147483648 -(bytes->integer (bytes 128 0 0 0) 4) => 2147483648 -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1185"></A> -</P> -<DL> -<DT><U>Function:</U> <B>integer->bytes</B> <I>n len</I> -<DD><P> - -Converts the integer <VAR>n</VAR> to a byte-array of <CODE>(abs <VAR>n</VAR>)</CODE> -bytes. If <VAR>n</VAR> and <VAR>len</VAR> are both negative, then the bytes in the -returned array are coded two's-complement. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(bytes->list (integer->bytes 15 -4)) => (0 0 0 15) -(bytes->list (integer->bytes 15 4)) => (0 0 0 15) -(bytes->list (integer->bytes -1 -4)) => (255 255 255 255) -(bytes->list (integer->bytes 4294967295 4)) => (255 255 255 255) -(bytes->list (integer->bytes -2147483648 -4)) => (128 0 0 0) -(bytes->list (integer->bytes 2147483648 4)) => (128 0 0 0) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1186"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes->ieee-float</B> <I>bytes</I> -<DD><P> - -<VAR>bytes</VAR> must be a 4-element byte-array. <CODE>bytes->ieee-float</CODE> calculates and returns the -value of <VAR>bytes</VAR> interpreted as a big-endian IEEE 4-byte (32-bit) number. -</P> -</DL> -<TABLE><tr><td> </td><td class=example><pre>(bytes->ieee-float (bytes #x40 0 0 0)) => 2.0 -(bytes->ieee-float (bytes #x40 #xd0 0 0)) => 6.5 -(bytes->ieee-float (bytes #xc0 #xd0 0 0)) => -6.5 - -(bytes->ieee-float (bytes 0 #x80 0 0)) => 11.754943508222875e-39 -(bytes->ieee-float (bytes 0 #x40 0 0)) => 5.877471754111437e-39 -(bytes->ieee-float (bytes 0 0 0 1)) => 1.401298464324817e-45 - -(bytes->ieee-float (bytes #xff #x80 0 0)) => -1/0 -(bytes->ieee-float (bytes #x7f #x80 0 0)) => 1/0 -(bytes->ieee-float (bytes #x7f #x80 0 1)) => 0/0 -</pre></td></tr></table><P> - -<A NAME="IDX1187"></A> -</P> -<DL> -<DT><U>Function:</U> <B>bytes->ieee-double</B> <I>bytes</I> -<DD><P> - -<VAR>bytes</VAR> must be a 8-element byte-array. <CODE>bytes->ieee-double</CODE> calculates and returns the -value of <VAR>bytes</VAR> interpreted as a big-endian IEEE 8-byte (64-bit) number. -</P> -</DL> -<TABLE><tr><td> </td><td class=example><pre>(bytes->ieee-double (bytes 0 0 0 0 0 0 0 0)) => 0.0 -(bytes->ieee-double (bytes #x40 0 0 0 0 0 0 0)) => 2 -(bytes->ieee-double (bytes #x40 #x1A 0 0 0 0 0 0)) => 6.5 -(bytes->ieee-double (bytes #xC0 #x1A 0 0 0 0 0 0)) => -6.5 - -(bytes->ieee-double (bytes 0 8 0 0 0 0 0 0)) => 11.125369292536006e-309 -(bytes->ieee-double (bytes 0 4 0 0 0 0 0 0)) => 5.562684646268003e-309 -(bytes->ieee-double (bytes 0 0 0 0 0 0 0 1)) => 4.0e-324 - -(bytes->ieee-double (bytes #xFF #xF0 0 0 0 0 0 0)) => -1/0 -(bytes->ieee-double (bytes #x7F #xF0 0 0 0 0 0 0)) => 1/0 -(bytes->ieee-double (bytes #x7F #xF8 0 0 0 0 0 0)) => 0/0 -</pre></td></tr></table><P> - -<A NAME="IDX1188"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ieee-float->bytes</B> <I>x</I> -<DD><P> - -Returns a 4-element byte-array encoding the IEEE single-precision -floating-point of <VAR>x</VAR>. -</P> -</DL> -<TABLE><tr><td> </td><td class=example><pre>(bytes->list (ieee-float->bytes 2.0)) => (64 0 0 0) -(bytes->list (ieee-float->bytes 6.5)) => (64 208 0 0) -(bytes->list (ieee-float->bytes -6.5)) => (192 208 0 0) - -(bytes->list (ieee-float->bytes 11.754943508222875e-39)) => ( 0 128 0 0) -(bytes->list (ieee-float->bytes 5.877471754111438e-39)) => ( 0 64 0 0) -(bytes->list (ieee-float->bytes 1.401298464324817e-45)) => ( 0 0 0 1) - -(bytes->list (ieee-float->bytes -1/0)) => (255 128 0 0) -(bytes->list (ieee-float->bytes 1/0)) => (127 128 0 0) -(bytes->list (ieee-float->bytes 0/0)) => (127 128 0 1) -</pre></td></tr></table><P> - -<A NAME="IDX1189"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ieee-double->bytes</B> <I>x</I> -<DD><P> - -Returns a 8-element byte-array encoding the IEEE double-precision -floating-point of <VAR>x</VAR>. -</P> -</DL> -<TABLE><tr><td> </td><td class=example><pre>(bytes->list (ieee-double->bytes 2.0)) => (64 0 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes 6.5)) => (64 26 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes -6.5)) => (192 26 0 0 0 0 0 0) - -(bytes->list (ieee-double->bytes 11.125369292536006e-309)) - => ( 0 8 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes 5.562684646268003e-309)) - => ( 0 4 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes 4.0e-324)) - => ( 0 0 0 0 0 0 0 1) - -(bytes->list (ieee-double->bytes -1/0)) => (255 240 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes 1/0)) => (127 240 0 0 0 0 0 0) -(bytes->list (ieee-double->bytes 0/0)) => (127 248 0 0 0 0 0 0) -</pre></td></tr></table><P> - -<A NAME="SEC191"></A> -<H4> Byte Collation Order </H4> -<!--docid::SEC191::--> -<P> - -The <CODE>string<?</CODE> ordering of big-endian byte-array -representations of fixed and IEEE floating-point numbers agrees with -the numerical ordering only when those numbers are non-negative. -</P> -<P> - -Straighforward modification of these formats can extend the -byte-collating order to work for their entire ranges. This -agreement enables the full range of numbers as keys in -<EM>indexed-sequential-access-method</EM> databases. -<A NAME="IDX1190"></A> -</P> -<P> - -<A NAME="IDX1191"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>integer-byte-collate!</B> <I>byte-vector</I> -<DD><P> - -Modifies sign bit of <VAR>byte-vector</VAR> so that <CODE>string<?</CODE> ordering of -two's-complement byte-vectors matches numerical order. <CODE>integer-byte-collate!</CODE> returns -<VAR>byte-vector</VAR> and is its own functional inverse. -</P> -</DL> -<P> - -<A NAME="IDX1192"></A> -</P> -<DL> -<DT><U>Function:</U> <B>integer-byte-collate</B> <I>byte-vector</I> -<DD><P> - -Returns copy of <VAR>byte-vector</VAR> with sign bit modified so that <CODE>string<?</CODE> -ordering of two's-complement byte-vectors matches numerical order. -<CODE>integer-byte-collate</CODE> is its own functional inverse. -</P> -</DL> -<P> - -<A NAME="IDX1193"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>ieee-byte-collate!</B> <I>byte-vector</I> -<DD><P> - -Modifies <VAR>byte-vector</VAR> so that <CODE>string<?</CODE> ordering of IEEE floating-point -byte-vectors matches numerical order. <CODE>ieee-byte-collate!</CODE> returns <VAR>byte-vector</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1194"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>ieee-byte-decollate!</B> <I>byte-vector</I> -<DD><P> - -Given <VAR>byte-vector</VAR> modified by <CODE>IEEE-byte-collate!</CODE>, reverses the <VAR>byte-vector</VAR> -modifications. -</P> -</DL> -<P> - -<A NAME="IDX1195"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ieee-byte-collate</B> <I>byte-vector</I> -<DD><P> - -Returns copy of <VAR>byte-vector</VAR> encoded so that <CODE>string<?</CODE> ordering of IEEE -floating-point byte-vectors matches numerical order. -</P> -</DL> -<P> - -<A NAME="IDX1196"></A> -</P> -<DL> -<DT><U>Function:</U> <B>ieee-byte-decollate</B> <I>byte-vector</I> -<DD><P> - -Given <VAR>byte-vector</VAR> returned by <CODE>IEEE-byte-collate</CODE>, reverses the <VAR>byte-vector</VAR> -modifications. -</P> -</DL> -<P> - -<A NAME="MAT-File Format"></A> -<HR SIZE="6"> -<A NAME="SEC192"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC190"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC193"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.7 MAT-File Format </H3> -<!--docid::SEC192::--> -<P> - -<CODE>(require 'matfile)</CODE> -<A NAME="IDX1197"></A> -<A NAME="IDX1198"></A> -</P> -<P> - -<A HREF="http://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf">http://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf</A> -</P> -<P> - -This package reads MAT-File Format version 4 (MATLAB) binary data -files. MAT-files written from big-endian or little-endian computers -having IEEE format numbers are currently supported. Support for files -written from VAX or Cray machines could also be added. -</P> -<P> - -The numeric and text matrix types handled; support for <EM>sparse</EM> -<A NAME="IDX1199"></A> -matrices awaits a sample file. -</P> -<P> - -<A NAME="IDX1200"></A> -</P> -<DL> -<DT><U>Function:</U> <B>matfile:read</B> <I>filename</I> -<DD><VAR>filename</VAR> should be a string naming an existing file containing a -MATLAB Version 4 MAT-File. The <CODE>matfile:read</CODE> procedure reads matrices from the -file and returns a list of the results; a list of the name string and -array for each matrix. -</DL> -<P> - -<A NAME="IDX1201"></A> -</P> -<DL> -<DT><U>Function:</U> <B>matfile:load</B> <I>filename</I> -<DD><VAR>filename</VAR> should be a string naming an existing file containing a -MATLAB Version 4 MAT-File. The <CODE>matfile:load</CODE> procedure reads matrices from the -file and defines the <CODE>string-ci->symbol</CODE> for each matrix to its -corresponding array. <CODE>matfile:load</CODE> returns a list of the symbols defined. -</DL> -<P> - -<A NAME="Portable Image Files"></A> -<HR SIZE="6"> -<A NAME="SEC193"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC192"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC194"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.8 Portable Image Files </H3> -<!--docid::SEC193::--> -<P> - -<CODE>(require 'pnm)</CODE> -<A NAME="IDX1202"></A> -</P> -<P> - -<A NAME="IDX1203"></A> -</P> -<DL> -<DT><U>Function:</U> <B>pnm:type-dimensions</B> <I>path</I> -<DD><P> - -The string <VAR>path</VAR> must name a <EM>portable bitmap graphics</EM> file. -<A NAME="IDX1204"></A> -<CODE>pnm:type-dimensions</CODE> returns a list of 4 items: -<OL> -<LI> -A symbol describing the type of the file named by <VAR>path</VAR>. -<LI> -The image width in pixels. -<LI> -The image height in pixels. -<LI> -The maximum value of pixels assume in the file. -</OL> -<P> - -The current set of file-type symbols is: -</P> -<DL COMPACT> -<DT>pbm -<DD><DT>pbm-raw -<DD><A NAME="IDX1205"></A> -<A NAME="IDX1206"></A> -Black-and-White image; pixel values are 0 or 1. -<DT>pgm -<DD><DT>pgm-raw -<DD><A NAME="IDX1207"></A> -<A NAME="IDX1208"></A> -Gray (monochrome) image; pixel values are from 0 to <VAR>maxval</VAR> -specified in file header. -<DT>ppm -<DD><DT>ppm-raw -<DD><A NAME="IDX1209"></A> -<A NAME="IDX1210"></A> -RGB (full color) image; red, green, and blue interleaved pixel values -are from 0 to <VAR>maxval</VAR> -</DL> -</DL> -<P> - -<A NAME="IDX1211"></A> -</P> -<DL> -<DT><U>Function:</U> <B>pnm:image-file->array</B> <I>path array</I> -<DD><P> - -Reads the <EM>portable bitmap graphics</EM> file named by <VAR>path</VAR> into -<A NAME="IDX1212"></A> -<VAR>array</VAR>. <VAR>array</VAR> must be the correct size and type for -<VAR>path</VAR>. <VAR>array</VAR> is returned. -</P> -<P> - -<A NAME="IDX1213"></A> -<DT><U>Function:</U> <B>pnm:image-file->array</B> <I>path</I> -<DD></P> -<P> - -<CODE>pnm:image-file->array</CODE> creates and returns an array with the -<EM>portable bitmap graphics</EM> file named by <VAR>path</VAR> read into it. -<A NAME="IDX1214"></A> -</P> -</DL> -<P> - -<A NAME="IDX1215"></A> -</P> -<DL> -<DT><U>Function:</U> <B>pnm:array-write</B> <I>type array maxval path comment <small>...</small></I> -<DD><P> - -Writes the contents of <VAR>array</VAR> to a <VAR>type</VAR> image file named <VAR>path</VAR>. The file -will have pixel values between 0 and <VAR>maxval</VAR>, which must be compatible -with <VAR>type</VAR>. For `<SAMP>pbm</SAMP>' files, <VAR>maxval</VAR> must be `<SAMP>1</SAMP>'. -<VAR>comment</VAR>s are included in the file header. -</P> -</DL> -<P> - -<A NAME="Collections"></A> -<HR SIZE="6"> -<A NAME="SEC194"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC193"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC195"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.9 Collections </H3> -<!--docid::SEC194::--> -<P> - -<CODE>(require 'collect)</CODE> -<A NAME="IDX1216"></A> -</P> -<P> - -Routines for managing collections. Collections are aggregate data -structures supporting iteration over their elements, similar to the -Dylan(TM) language, but with a different interface. They have -<EM>elements</EM> indexed by corresponding <EM>keys</EM>, although the keys -may be implicit (as with lists). -</P> -<P> - -New types of collections may be defined as YASOS objects (see section <A HREF="slib_3.html#SEC40">3.8 Yasos</A>). -They must support the following operations: -</P> -<P> - -<UL> -<LI> -<CODE>(collection? <VAR>self</VAR>)</CODE> (always returns <CODE>#t</CODE>); -<P> - -</P> -<LI> -<CODE>(size <VAR>self</VAR>)</CODE> returns the number of elements in the collection; -<P> - -</P> -<LI> -<CODE>(print <VAR>self</VAR> <VAR>port</VAR>)</CODE> is a specialized print operation -for the collection which prints a suitable representation on the given -<VAR>port</VAR> or returns it as a string if <VAR>port</VAR> is <CODE>#t</CODE>; -<P> - -</P> -<LI> -<A NAME="IDX1217"></A> -<CODE>(gen-elts <VAR>self</VAR>)</CODE> returns a thunk which on successive -invocations yields elements of <VAR>self</VAR> in order or gives an error if -it is invoked more than <CODE>(size <VAR>self</VAR>)</CODE> times; -<P> - -</P> -<LI> -<A NAME="IDX1218"></A> -<CODE>(gen-keys <VAR>self</VAR>)</CODE> is like <CODE>gen-elts</CODE>, but yields the -collection's keys in order. -</UL> -<P> - -They might support specialized <CODE>for-each-key</CODE> and -<CODE>for-each-elt</CODE> operations. -</P> -<P> - -<A NAME="IDX1219"></A> -</P> -<DL> -<DT><U>Function:</U> <B>collection?</B> <I>obj</I> -<DD>A predicate, true initially of lists, vectors and strings. New sorts of -collections must answer <CODE>#t</CODE> to <CODE>collection?</CODE>. -</DL> -<P> - -<A NAME="IDX1220"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>map-elts</B> <I>proc collection1 <small>...</small></I> -<DD><A NAME="IDX1221"></A> -<DT><U>Procedure:</U> <B>do-elts</B> <I>proc collection1 <small>...</small></I> -<DD><VAR>proc</VAR> is a procedure taking as many arguments as there are -<VAR>collections</VAR> (at least one). The <VAR>collections</VAR> are iterated -over in their natural order and <VAR>proc</VAR> is applied to the elements -yielded by each iteration in turn. The order in which the arguments are -supplied corresponds to te order in which the <VAR>collections</VAR> appear. -<CODE>do-elts</CODE> is used when only side-effects of <VAR>proc</VAR> are of -interest and its return value is unspecified. <CODE>map-elts</CODE> returns a -collection (actually a vector) of the results of the applications of -<VAR>proc</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(map-elts + (list 1 2 3) (vector 1 2 3)) - => #(2 4 6) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1222"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>map-keys</B> <I>proc collection1 <small>...</small></I> -<DD><A NAME="IDX1223"></A> -<DT><U>Procedure:</U> <B>do-keys</B> <I>proc collection1 <small>...</small></I> -<DD>These are analogous to <CODE>map-elts</CODE> and <CODE>do-elts</CODE>, but each -iteration is over the <VAR>collections</VAR>' <EM>keys</EM> rather than their -elements. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(map-keys + (list 1 2 3) (vector 1 2 3)) - => #(0 2 4) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1224"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>for-each-key</B> <I>collection proc</I> -<DD><A NAME="IDX1225"></A> -<DT><U>Procedure:</U> <B>for-each-elt</B> <I>collection proc</I> -<DD>These are like <CODE>do-keys</CODE> and <CODE>do-elts</CODE> but only for a single -collection; they are potentially more efficient. -</DL> -<P> - -<A NAME="IDX1226"></A> -</P> -<DL> -<DT><U>Function:</U> <B>reduce</B> <I>proc seed collection1 <small>...</small></I> -<DD>A generalization of the list-based <CODE>reduce-init</CODE> -(see section <A HREF="slib_7.html#SEC211">7.2.1.3 Lists as sequences</A>) to collections which will shadow the -list-based version if <CODE>(require 'collect)</CODE> follows -<A NAME="IDX1227"></A> -<CODE>(require 'common-list-functions)</CODE> (see section <A HREF="slib_7.html#SEC208">7.2.1 Common List Functions</A>). -<A NAME="IDX1228"></A> -<P> - -Examples: -<TABLE><tr><td> </td><td class=example><pre>(reduce + 0 (vector 1 2 3)) - => 6 -(reduce union '() '((a b c) (b c d) (d a))) - => (c b d a). -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1229"></A> -</P> -<DL> -<DT><U>Function:</U> <B>any?</B> <I>pred collection1 <small>...</small></I> -<DD>A generalization of the list-based <CODE>some</CODE> (see section <A HREF="slib_7.html#SEC211">7.2.1.3 Lists as sequences</A>) to collections. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(any? odd? (list 2 3 4 5)) - => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1230"></A> -</P> -<DL> -<DT><U>Function:</U> <B>every?</B> <I>pred collection1 <small>...</small></I> -<DD>A generalization of the list-based <CODE>every</CODE> -(see section <A HREF="slib_7.html#SEC211">7.2.1.3 Lists as sequences</A>) to collections. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(every? collection? '((1 2) #(1 2))) - => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1231"></A> -</P> -<DL> -<DT><U>Function:</U> <B>empty?</B> <I>collection</I> -<DD>Returns <CODE>#t</CODE> iff there are no elements in <VAR>collection</VAR>. -<P> - -<CODE>(empty? <VAR>collection</VAR>) == (zero? (size <VAR>collection</VAR>))</CODE> -</P> -</DL> -<P> - -<A NAME="IDX1232"></A> -</P> -<DL> -<DT><U>Function:</U> <B>size</B> <I>collection</I> -<DD>Returns the number of elements in <VAR>collection</VAR>. -</DL> -<P> - -<A NAME="IDX1233"></A> -</P> -<DL> -<DT><U>Function:</U> <B>Setter</B> <I>list-ref</I> -<DD>See <A HREF="slib_3.html#SEC43">3.8.3 Setters</A> for a definition of <EM>setter</EM>. N.B. -<CODE>(setter list-ref)</CODE> doesn't work properly for element 0 of a -list. -</DL> -<P> - -Here is a sample collection: <CODE>simple-table</CODE> which is also a -<CODE>table</CODE>. -<TABLE><tr><td> </td><td class=example><pre>(define-predicate TABLE?) -(define-operation (LOOKUP table key failure-object)) -(define-operation (ASSOCIATE! table key value)) ;; returns key -(define-operation (REMOVE! table key)) ;; returns value - -(define (MAKE-SIMPLE-TABLE) - (let ( (table (list)) ) - (object - ;; table behaviors - ((TABLE? self) #t) - ((SIZE self) (size table)) - ((PRINT self port) (format port "#<SIMPLE-TABLE>")) - ((LOOKUP self key failure-object) - (cond - ((assq key table) => cdr) - (else failure-object) - )) - ((ASSOCIATE! self key value) - (cond - ((assq key table) - => (lambda (bucket) (set-cdr! bucket value) key)) - (else - (set! table (cons (cons key value) table)) - key) - )) - ((REMOVE! self key);; returns old value - (cond - ((null? table) (slib:error "TABLE:REMOVE! Key not found: " key)) - ((eq? key (caar table)) - (let ( (value (cdar table)) ) - (set! table (cdr table)) - value) - ) - (else - (let loop ( (last table) (this (cdr table)) ) - (cond - ((null? this) - (slib:error "TABLE:REMOVE! Key not found: " key)) - ((eq? key (caar this)) - (let ( (value (cdar this)) ) - (set-cdr! last (cdr this)) - value) - ) - (else - (loop (cdr last) (cdr this))) - ) ) ) - )) - ;; collection behaviors - ((COLLECTION? self) #t) - ((GEN-KEYS self) (collect:list-gen-elts (map car table))) - ((GEN-ELTS self) (collect:list-gen-elts (map cdr table))) - ((FOR-EACH-KEY self proc) - (for-each (lambda (bucket) (proc (car bucket))) table) - ) - ((FOR-EACH-ELT self proc) - (for-each (lambda (bucket) (proc (cdr bucket))) table) - ) ) ) ) -</pre></td></tr></table><P> - -<A NAME="Dynamic Data Type"></A> -<HR SIZE="6"> -<A NAME="SEC195"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC194"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC196"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.10 Dynamic Data Type </H3> -<!--docid::SEC195::--> -<P> - -<CODE>(require 'dynamic)</CODE> -<A NAME="IDX1234"></A> -</P> -<P> - -<A NAME="IDX1235"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-dynamic</B> <I>obj</I> -<DD>Create and returns a new <EM>dynamic</EM> whose global value is <VAR>obj</VAR>. -</DL> -<P> - -<A NAME="IDX1236"></A> -</P> -<DL> -<DT><U>Function:</U> <B>dynamic?</B> <I>obj</I> -<DD>Returns true if and only if <VAR>obj</VAR> is a dynamic. No object -satisfying <CODE>dynamic?</CODE> satisfies any of the other standard type -predicates. -</DL> -<P> - -<A NAME="IDX1237"></A> -</P> -<DL> -<DT><U>Function:</U> <B>dynamic-ref</B> <I>dyn</I> -<DD>Return the value of the given dynamic in the current dynamic -environment. -</DL> -<P> - -<A NAME="IDX1238"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>dynamic-set!</B> <I>dyn obj</I> -<DD>Change the value of the given dynamic to <VAR>obj</VAR> in the current -dynamic environment. The returned value is unspecified. -</DL> -<P> - -<A NAME="IDX1239"></A> -</P> -<DL> -<DT><U>Function:</U> <B>call-with-dynamic-binding</B> <I>dyn obj thunk</I> -<DD>Invoke and return the value of the given thunk in a new, nested dynamic -environment in which the given dynamic has been bound to a new location -whose initial contents are the value <VAR>obj</VAR>. This dynamic -environment has precisely the same extent as the invocation of the thunk -and is thus captured by continuations created within that invocation and -re-established by those continuations when they are invoked. -</DL> -<P> - -The <CODE>dynamic-bind</CODE> macro is not implemented. -</P> -<P> - -<A NAME="Hash Tables"></A> -<HR SIZE="6"> -<A NAME="SEC196"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC195"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC197"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.11 Hash Tables </H3> -<!--docid::SEC196::--> -<P> - -<CODE>(require 'hash-table)</CODE> -<A NAME="IDX1240"></A> -</P> -<P> - -<A NAME="IDX1241"></A> -</P> -<DL> -<DT><U>Function:</U> <B>predicate->hash</B> <I>pred</I> -<DD><P> - -Returns a hash function (like <CODE>hashq</CODE>, <CODE>hashv</CODE>, or -<CODE>hash</CODE>) corresponding to the equality predicate <VAR>pred</VAR>. -<VAR>pred</VAR> should be <CODE>eq?</CODE>, <CODE>eqv?</CODE>, <CODE>equal?</CODE>, <CODE>=</CODE>, -<CODE>char=?</CODE>, <CODE>char-ci=?</CODE>, <CODE>string=?</CODE>, or -<CODE>string-ci=?</CODE>. -</P> -</DL> -A hash table is a vector of association lists. -<P> - -<A NAME="IDX1242"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-hash-table</B> <I>k</I> -<DD><P> - -Returns a vector of <VAR>k</VAR> empty (association) lists. -</P> -</DL> -Hash table functions provide utilities for an associative database. -These functions take an equality predicate, <VAR>pred</VAR>, as an argument. -<VAR>pred</VAR> should be <CODE>eq?</CODE>, <CODE>eqv?</CODE>, <CODE>equal?</CODE>, <CODE>=</CODE>, -<CODE>char=?</CODE>, <CODE>char-ci=?</CODE>, <CODE>string=?</CODE>, or -<CODE>string-ci=?</CODE>. -<P> - -<A NAME="IDX1243"></A> -</P> -<DL> -<DT><U>Function:</U> <B>predicate->hash-asso</B> <I>pred</I> -<DD><P> - -Returns a hash association function of 2 arguments, <VAR>key</VAR> and -<VAR>hashtab</VAR>, corresponding to <VAR>pred</VAR>. The returned function -returns a key-value pair whose key is <VAR>pred</VAR>-equal to its first -argument or <CODE>#f</CODE> if no key in <VAR>hashtab</VAR> is <VAR>pred</VAR>-equal to -the first argument. -</P> -</DL> -<P> - -<A NAME="IDX1244"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-inquirer</B> <I>pred</I> -<DD><P> - -Returns a procedure of 2 arguments, <VAR>hashtab</VAR> and <VAR>key</VAR>, which -returns the value associated with <VAR>key</VAR> in <VAR>hashtab</VAR> or -<CODE>#f</CODE> if <VAR>key</VAR> does not appear in <VAR>hashtab</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1245"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-associator</B> <I>pred</I> -<DD><P> - -Returns a procedure of 3 arguments, <VAR>hashtab</VAR>, <VAR>key</VAR>, and -<VAR>value</VAR>, which modifies <VAR>hashtab</VAR> so that <VAR>key</VAR> and -<VAR>value</VAR> associated. Any previous value associated with <VAR>key</VAR> -will be lost. -</P> -</DL> -<P> - -<A NAME="IDX1246"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-remover</B> <I>pred</I> -<DD><P> - -Returns a procedure of 2 arguments, <VAR>hashtab</VAR> and <VAR>key</VAR>, which -modifies <VAR>hashtab</VAR> so that the association whose key is <VAR>key</VAR> is -removed. -</P> -</DL> -<P> - -<A NAME="IDX1247"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-map</B> <I>proc hash-table</I> -<DD><P> - -Returns a new hash table formed by mapping <VAR>proc</VAR> over the -keys and values of <VAR>hash-table</VAR>. <VAR>proc</VAR> must be a function of 2 -arguments which returns the new value part. -</P> -</DL> -<P> - -<A NAME="IDX1248"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-for-each</B> <I>proc hash-table</I> -<DD><P> - -Applies <VAR>proc</VAR> to each pair of keys and values of <VAR>hash-table</VAR>. -<VAR>proc</VAR> must be a function of 2 arguments. The returned value is -unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1249"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hash-rehasher</B> <I>pred</I> -<DD><P> - -<CODE>hash-rehasher</CODE> accepts a hash table predicate and returns a function of two -arguments <VAR>hashtab</VAR> and <VAR>new-k</VAR> which is specialized for -that predicate. -</P> -<P> - -This function is used for nondestrutively resizing a hash table. -<VAR>hashtab</VAR> should be an existing hash-table using <VAR>pred</VAR>, <VAR>new-k</VAR> -is the size of a new hash table to be returned. The new hash table -will have all of the associations of the old hash table. -</P> -</DL> -<P> - -<A NAME="Object"></A> -<HR SIZE="6"> -<A NAME="SEC197"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC196"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC198"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.12 Macroless Object System </H3> -<!--docid::SEC197::--> -<P> - -<CODE>(require 'object)</CODE> -<A NAME="IDX1250"></A> -</P> -<P> - -This is the Macroless Object System written by Wade Humeniuk -(whumeniu@datap.ca). Conceptual Tributes: <A HREF="slib_3.html#SEC40">3.8 Yasos</A>, MacScheme's -%object, CLOS, Lack of R4RS macros. -</P> -<P> - -<HR SIZE="6"> -<A NAME="SEC198"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC197"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC199"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.13 Concepts </H3> -<!--docid::SEC198::--> -<DL COMPACT> - -<DT>OBJECT -<DD>An object is an ordered association-list (by <CODE>eq?</CODE>) of methods -(procedures). Methods can be added (<CODE>make-method!</CODE>), deleted -(<CODE>unmake-method!</CODE>) and retrieved (<CODE>get-method</CODE>). Objects may -inherit methods from other objects. The object binds to the environment -it was created in, allowing closures to be used to hide private -procedures and data. -<P> - -</P> -<DT>GENERIC-METHOD -<DD>A generic-method associates (in terms of <CODE>eq?</CODE>) object's method. -This allows scheme function style to be used for objects. The calling -scheme for using a generic method is <CODE>(generic-method object param1 -param2 ...)</CODE>. -<P> - -</P> -<DT>METHOD -<DD>A method is a procedure that exists in the object. To use a method -get-method must be called to look-up the method. Generic methods -implement the get-method functionality. Methods may be added to an -object associated with any scheme obj in terms of eq? -<P> - -</P> -<DT>GENERIC-PREDICATE -<DD>A generic method that returns a boolean value for any scheme obj. -<P> - -</P> -<DT>PREDICATE -<DD>A object's method asscociated with a generic-predicate. Returns -<CODE>#t</CODE>. -</DL> -<P> - -<HR SIZE="6"> -<A NAME="SEC199"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC198"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC200"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.14 Procedures </H3> -<!--docid::SEC199::--> -<P> - -<A NAME="IDX1251"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-object</B> <I>ancestor <small>...</small></I> -<DD>Returns an object. Current object implementation is a tagged vector. -<VAR>ancestor</VAR>s are optional and must be objects in terms of object?. -<VAR>ancestor</VAR>s methods are included in the object. Multiple -<VAR>ancestor</VAR>s might associate the same generic-method with a method. -In this case the method of the <VAR>ancestor</VAR> first appearing in the -list is the one returned by <CODE>get-method</CODE>. -</DL> -<P> - -<A NAME="IDX1252"></A> -</P> -<DL> -<DT><U>Function:</U> <B>object?</B> <I>obj</I> -<DD>Returns boolean value whether <VAR>obj</VAR> was created by make-object. -</DL> -<P> - -<A NAME="IDX1253"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-generic-method</B> <I>exception-procedure</I> -<DD>Returns a procedure which be associated with an object's methods. If -<VAR>exception-procedure</VAR> is specified then it is used to process -non-objects. -</DL> -<P> - -<A NAME="IDX1254"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-generic-predicate</B> -<DD>Returns a boolean procedure for any scheme object. -</DL> -<P> - -<A NAME="IDX1255"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-method!</B> <I>object generic-method method</I> -<DD>Associates <VAR>method</VAR> to the <VAR>generic-method</VAR> in the object. The -<VAR>method</VAR> overrides any previous association with the -<VAR>generic-method</VAR> within the object. Using <CODE>unmake-method!</CODE> -will restore the object's previous association with the -<VAR>generic-method</VAR>. <VAR>method</VAR> must be a procedure. -</DL> -<P> - -<A NAME="IDX1256"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-predicate!</B> <I>object generic-preciate</I> -<DD>Makes a predicate method associated with the <VAR>generic-predicate</VAR>. -</DL> -<P> - -<A NAME="IDX1257"></A> -</P> -<DL> -<DT><U>Function:</U> <B>unmake-method!</B> <I>object generic-method</I> -<DD>Removes an object's association with a <VAR>generic-method</VAR> . -</DL> -<P> - -<A NAME="IDX1258"></A> -</P> -<DL> -<DT><U>Function:</U> <B>get-method</B> <I>object generic-method</I> -<DD>Returns the object's method associated (if any) with the -<VAR>generic-method</VAR>. If no associated method exists an error is -flagged. -</DL> -<P> - -<HR SIZE="6"> -<A NAME="SEC200"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC199"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC201"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.15 Examples </H3> -<!--docid::SEC200::--> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(require 'object) -<A NAME="IDX1259"></A> -(define instantiate (make-generic-method)) - -(define (make-instance-object . ancestors) - (define self (apply make-object - (map (lambda (obj) (instantiate obj)) ancestors))) - (make-method! self instantiate (lambda (self) self)) - self) - -(define who (make-generic-method)) -(define imigrate! (make-generic-method)) -(define emigrate! (make-generic-method)) -(define describe (make-generic-method)) -(define name (make-generic-method)) -(define address (make-generic-method)) -(define members (make-generic-method)) - -(define society - (let () - (define self (make-instance-object)) - (define population '()) - (make-method! self imigrate! - (lambda (new-person) - (if (not (eq? new-person self)) - (set! population (cons new-person population))))) - (make-method! self emigrate! - (lambda (person) - (if (not (eq? person self)) - (set! population - (comlist:remove-if (lambda (member) - (eq? member person)) - population))))) - (make-method! self describe - (lambda (self) - (map (lambda (person) (describe person)) population))) - (make-method! self who - (lambda (self) (map (lambda (person) (name person)) - population))) - (make-method! self members (lambda (self) population)) - self)) - -(define (make-person %name %address) - (define self (make-instance-object society)) - (make-method! self name (lambda (self) %name)) - (make-method! self address (lambda (self) %address)) - (make-method! self who (lambda (self) (name self))) - (make-method! self instantiate - (lambda (self) - (make-person (string-append (name self) "-son-of") - %address))) - (make-method! self describe - (lambda (self) (list (name self) (address self)))) - (imigrate! self) - self) -</pre></td></tr></table><P> - -<HR SIZE="6"> -<A NAME="SEC201"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC200"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC202"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.1.15.1 Inverter Documentation </H4> -<!--docid::SEC201::--> -Inheritance: -<TABLE><tr><td> </td><td class=example><pre> <inverter>::(<number> <description>) -</pre></td></tr></table>Generic-methods -<TABLE><tr><td> </td><td class=example><pre> <inverter>::value => <number>::value - <inverter>::set-value! => <number>::set-value! - <inverter>::describe => <description>::describe - <inverter>::help - <inverter>::invert - <inverter>::inverter? -</pre></td></tr></table><P> - -<HR SIZE="6"> -<A NAME="SEC202"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC201"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC203"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.1.15.2 Number Documention </H4> -<!--docid::SEC202::--> -Inheritance -<TABLE><tr><td> </td><td class=example><pre> <number>::() -</pre></td></tr></table>Slots -<TABLE><tr><td> </td><td class=example><pre> <number>::<x> -</pre></td></tr></table>Generic Methods -<TABLE><tr><td> </td><td class=example><pre> <number>::value - <number>::set-value! -</pre></td></tr></table><P> - -<HR SIZE="6"> -<A NAME="SEC203"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC202"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC204"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.1.15.3 Inverter code </H4> -<!--docid::SEC203::--> -<TABLE><tr><td> </td><td class=example><pre>(require 'object) -<A NAME="IDX1260"></A> -(define value (make-generic-method (lambda (val) val))) -(define set-value! (make-generic-method)) -(define invert (make-generic-method - (lambda (val) - (if (number? val) - (/ 1 val) - (error "Method not supported:" val))))) -(define noop (make-generic-method)) -(define inverter? (make-generic-predicate)) -(define describe (make-generic-method)) -(define help (make-generic-method)) - -(define (make-number x) - (define self (make-object)) - (make-method! self value (lambda (this) x)) - (make-method! self set-value! - (lambda (this new-value) (set! x new-value))) - self) - -(define (make-description str) - (define self (make-object)) - (make-method! self describe (lambda (this) str)) - (make-method! self help (lambda (this) "Help not available")) - self) - -(define (make-inverter) - (let* ((self (make-object - (make-number 1) - (make-description "A number which can be inverted"))) - (<value> (get-method self value))) - (make-method! self invert (lambda (self) (/ 1 (<value> self)))) - (make-predicate! self inverter?) - (unmake-method! self help) - (make-method! self help - (lambda (self) - (display "Inverter Methods:") (newline) - (display " (value inverter) ==> n") (newline))) - self)) - -;;;; Try it out - -(define invert! (make-generic-method)) - -(define x (make-inverter)) - -(make-method! x invert! (lambda (x) (set-value! x (/ 1 (value x))))) - -(value x) => 1 -(set-value! x 33) => undefined -(invert! x) => undefined -(value x) => 1/33 - -(unmake-method! x invert!) => undefined - -(invert! x) error--> ERROR: Method not supported: x -</pre></td></tr></table><P> - -<A NAME="Priority Queues"></A> -<HR SIZE="6"> -<A NAME="SEC204"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC203"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC205"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.16 Priority Queues </H3> -<!--docid::SEC204::--> -<P> - -<CODE>(require 'priority-queue)</CODE> -<A NAME="IDX1261"></A> -</P> -<P> - -This algorithm for priority queues is due to -<CITE>Introduction to Algorithms</CITE> -by T. Cormen, C. Leiserson, R. Rivest. -1989 MIT Press. -</P> -<P> - -<A NAME="IDX1262"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-heap</B> <I>pred<?</I> -<DD><P> - -Returns a binary heap suitable which can be used for priority queue -operations. -</P> -</DL> -<P> - -<A NAME="IDX1263"></A> -</P> -<DL> -<DT><U>Function:</U> <B>heap-length</B> <I>heap</I> -<DD><P> - -Returns the number of elements in <VAR>heap</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1264"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>heap-insert!</B> <I>heap item</I> -<DD><P> - -Inserts <VAR>item</VAR> into <VAR>heap</VAR>. <VAR>item</VAR> can be inserted multiple -times. The value returned is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX1265"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>heap-extract-max!</B> <I>heap</I> -<DD><P> - -Returns the item which is larger than all others according to the -<VAR>pred<?</VAR> argument to <CODE>make-heap</CODE>. If there are no items in -<VAR>heap</VAR>, an error is signaled. -</P> -</DL> -<P> - -<A NAME="Queues"></A> -<HR SIZE="6"> -<A NAME="SEC205"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC204"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC206"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.17 Queues </H3> -<!--docid::SEC205::--> -<P> - -<CODE>(require 'queue)</CODE> -<A NAME="IDX1266"></A> -</P> -<P> - -A <EM>queue</EM> is a list where elements can be added to both the front -<A NAME="IDX1267"></A> -and rear, and removed from the front (i.e., they are what are often -called <EM>dequeues</EM>). A queue may also be used like a stack. -<A NAME="IDX1268"></A> -</P> -<P> - -<A NAME="IDX1269"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-queue</B> -<DD><P> - -Returns a new, empty queue. -</P> -</DL> -<P> - -<A NAME="IDX1270"></A> -</P> -<DL> -<DT><U>Function:</U> <B>queue?</B> <I>obj</I> -<DD><P> - -Returns <CODE>#t</CODE> if <VAR>obj</VAR> is a queue. -</P> -</DL> -<P> - -<A NAME="IDX1271"></A> -</P> -<DL> -<DT><U>Function:</U> <B>queue-empty?</B> <I>q</I> -<DD><P> - -Returns <CODE>#t</CODE> if the queue <VAR>q</VAR> is empty. -</P> -</DL> -<P> - -<A NAME="IDX1272"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>queue-push!</B> <I>q datum</I> -<DD><P> - -Adds <VAR>datum</VAR> to the front of queue <VAR>q</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1273"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>enqueue!</B> <I>q datum</I> -<DD><P> - -Adds <VAR>datum</VAR> to the rear of queue <VAR>q</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1274"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>dequeue!</B> <I>q</I> -<DD><P> - -<A NAME="IDX1275"></A> -<DT><U>Procedure:</U> <B>queue-pop!</B> <I>q</I> -<DD>Both of these procedures remove and return the datum at the front of -the queue. <CODE>queue-pop!</CODE> is used to suggest that the queue is -being used like a stack. -</P> -</DL> -All of the following functions raise an error if the queue <VAR>q</VAR> -is empty. -<P> - -<A NAME="IDX1276"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>dequeue-all!</B> <I>q</I> -<DD><P> - -Removes and returns (the list) of all contents of queue <VAR>q</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1277"></A> -</P> -<DL> -<DT><U>Function:</U> <B>queue-front</B> <I>q</I> -<DD><P> - -Returns the datum at the front of the queue <VAR>q</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1278"></A> -</P> -<DL> -<DT><U>Function:</U> <B>queue-rear</B> <I>q</I> -<DD><P> - -Returns the datum at the rear of the queue <VAR>q</VAR>. -</P> -</DL> -<P> - -<A NAME="Records"></A> -<HR SIZE="6"> -<A NAME="SEC206"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC205"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC184"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.1.18 Records </H3> -<!--docid::SEC206::--> -<P> - -<CODE>(require 'record)</CODE> -<A NAME="IDX1279"></A> -</P> -<P> - -The Record package provides a facility for user to define their own -record data types. -</P> -<P> - -<A NAME="IDX1280"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-record-type</B> <I>type-name field-names</I> -<DD>Returns a <EM>record-type descriptor</EM>, a value representing a new data -type disjoint from all others. The <VAR>type-name</VAR> argument must be a -string, but is only used for debugging purposes (such as the printed -representation of a record of the new type). The <VAR>field-names</VAR> -argument is a list of symbols naming the <EM>fields</EM> of a record of the -new type. It is an error if the list contains any duplicates. It is -unspecified how record-type descriptors are represented. -</DL> -<P> - -<A NAME="IDX1281"></A> -</P> -<DL> -<DT><U>Function:</U> <B>record-constructor</B> <I>rtd [field-names]</I> -<DD>Returns a procedure for constructing new members of the type represented -by <VAR>rtd</VAR>. The returned procedure accepts exactly as many arguments -as there are symbols in the given list, <VAR>field-names</VAR>; these are -used, in order, as the initial values of those fields in a new record, -which is returned by the constructor procedure. The values of any -fields not named in that list are unspecified. The <VAR>field-names</VAR> -argument defaults to the list of field names in the call to -<CODE>make-record-type</CODE> that created the type represented by <VAR>rtd</VAR>; -if the <VAR>field-names</VAR> argument is provided, it is an error if it -contains any duplicates or any symbols not in the default list. -</DL> -<P> - -<A NAME="IDX1282"></A> -</P> -<DL> -<DT><U>Function:</U> <B>record-predicate</B> <I>rtd</I> -<DD>Returns a procedure for testing membership in the type represented by -<VAR>rtd</VAR>. The returned procedure accepts exactly one argument and -returns a true value if the argument is a member of the indicated record -type; it returns a false value otherwise. -</DL> -<P> - -<A NAME="IDX1283"></A> -</P> -<DL> -<DT><U>Function:</U> <B>record-accessor</B> <I>rtd field-name</I> -<DD>Returns a procedure for reading the value of a particular field of a -member of the type represented by <VAR>rtd</VAR>. The returned procedure -accepts exactly one argument which must be a record of the appropriate -type; it returns the current value of the field named by the symbol -<VAR>field-name</VAR> in that record. The symbol <VAR>field-name</VAR> must be a -member of the list of field-names in the call to <CODE>make-record-type</CODE> -that created the type represented by <VAR>rtd</VAR>. -</DL> -<P> - -<A NAME="IDX1284"></A> -</P> -<DL> -<DT><U>Function:</U> <B>record-modifier</B> <I>rtd field-name</I> -<DD>Returns a procedure for writing the value of a particular field of a -member of the type represented by <VAR>rtd</VAR>. The returned procedure -accepts exactly two arguments: first, a record of the appropriate type, -and second, an arbitrary Scheme value; it modifies the field named by -the symbol <VAR>field-name</VAR> in that record to contain the given value. -The returned value of the modifier procedure is unspecified. The symbol -<VAR>field-name</VAR> must be a member of the list of field-names in the call -to <CODE>make-record-type</CODE> that created the type represented by -<VAR>rtd</VAR>. -</DL> -<P> - -In May of 1996, as a product of discussion on the <CODE>rrrs-authors</CODE> -mailing list, I rewrote `<TT>record.scm</TT>' to portably implement type -disjointness for record data types. -</P> -<P> - -As long as an implementation's procedures are opaque and the -<CODE>record</CODE> code is loaded before other programs, this will give -disjoint record types which are unforgeable and incorruptible by R4RS -procedures. -</P> -<P> - -As a consequence, the procedures <CODE>record?</CODE>, -<CODE>record-type-descriptor</CODE>, <CODE>record-type-name</CODE>.and -<CODE>record-type-field-names</CODE> are no longer supported. -</P> -<P> - -<A NAME="Sorting and Searching"></A> -<HR SIZE="6"> -<A NAME="SEC207"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC206"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.2 Sorting and Searching </H2> -<!--docid::SEC207::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC208">7.2.1 Common List Functions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'common-list-functions</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC214">7.2.2 Tree operations</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'tree</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC215">7.2.3 Chapter Ordering</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'chapter-order</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC216">7.2.4 Sorting</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'sort</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC217">7.2.5 Topological Sort</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Keep your socks on.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC218">7.2.6 Hashing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'hash</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC219">7.2.7 Space-Filling Curves</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'hilbert and 'sierpinski</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC222">7.2.8 Soundex</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Dimension Reduction of Last Names</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC223">7.2.9 String Search</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Also Search from a Port.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC224">7.2.10 Sequence Comparison</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'diff and longest-common-subsequence</TD></TR> -</TABLE> -<P> - -<A NAME="Common List Functions"></A> -<HR SIZE="6"> -<A NAME="SEC208"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC209"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.1 Common List Functions </H3> -<!--docid::SEC208::--> -<P> - -<CODE>(require 'common-list-functions)</CODE> -<A NAME="IDX1285"></A> -</P> -<P> - -The procedures below follow the Common LISP equivalents apart from -optional arguments in some cases. -</P> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC209">7.2.1.1 List construction</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC210">7.2.1.2 Lists as sets</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC211">7.2.1.3 Lists as sequences</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC212">7.2.1.4 Destructive list operations</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC213">7.2.1.5 Non-List functions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -</TABLE> -<P> - -<A NAME="List construction"></A> -<HR SIZE="6"> -<A NAME="SEC209"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC210"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.1.1 List construction </H4> -<!--docid::SEC209::--> -<P> - -<A NAME="IDX1286"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-list</B> <I>k</I> -<DD><A NAME="IDX1287"></A> -<DT><U>Function:</U> <B>make-list</B> <I>k init</I> -<DD><CODE>make-list</CODE> creates and returns a list of <VAR>k</VAR> elements. If -<VAR>init</VAR> is included, all elements in the list are initialized to -<VAR>init</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(make-list 3) - => (#<unspecified> #<unspecified> #<unspecified>) -(make-list 5 'foo) - => (foo foo foo foo foo) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1288"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list*</B> <I>obj1 obj2 <small>...</small></I> -<DD>Works like <CODE>list</CODE> except that the cdr of the last pair is the last -argument unless there is only one argument, when the result is just that -argument. Sometimes called <CODE>cons*</CODE>. E.g.: -<P> - -<TABLE><tr><td> </td><td class=example><pre>(list* 1) - => 1 -(list* 1 2 3) - => (1 2 . 3) -(list* 1 2 '(3 4)) - => (1 2 3 4) -(list* <VAR>args</VAR> '()) - == (list <VAR>args</VAR>) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1289"></A> -</P> -<DL> -<DT><U>Function:</U> <B>copy-list</B> <I>lst</I> -<DD><CODE>copy-list</CODE> makes a copy of <VAR>lst</VAR> using new pairs and returns -it. Only the top level of the list is copied, i.e., pairs forming -elements of the copied list remain <CODE>eq?</CODE> to the corresponding -elements of the original; the copy is, however, not <CODE>eq?</CODE> to the -original, but is <CODE>equal?</CODE> to it. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(copy-list '(foo foo foo)) - => (foo foo foo) -(define q '(foo bar baz bang)) -(define p q) -(eq? p q) - => #t -(define r (copy-list q)) -(eq? q r) - => #f -(equal? q r) - => #t -(define bar '(bar)) -(eq? bar (car (copy-list (list bar 'foo)))) -=> #t -</pre></td></tr></table></DL> -<P> - -<A NAME="Lists as sets"></A> -<HR SIZE="6"> -<A NAME="SEC210"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC209"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC211"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.1.2 Lists as sets </H4> -<!--docid::SEC210::--> -<P> - -<CODE>eqv?</CODE> is used to test for membership by procedures which treat -lists as sets. -</P> -<P> - -<A NAME="IDX1290"></A> -</P> -<DL> -<DT><U>Function:</U> <B>adjoin</B> <I>e l</I> -<DD><CODE>adjoin</CODE> returns the adjoint of the element <VAR>e</VAR> and the list -<VAR>l</VAR>. That is, if <VAR>e</VAR> is in <VAR>l</VAR>, <CODE>adjoin</CODE> returns -<VAR>l</VAR>, otherwise, it returns <CODE>(cons <VAR>e</VAR> <VAR>l</VAR>)</CODE>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(adjoin 'baz '(bar baz bang)) - => (bar baz bang) -(adjoin 'foo '(bar baz bang)) - => (foo bar baz bang) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1291"></A> -</P> -<DL> -<DT><U>Function:</U> <B>union</B> <I>l1 l2</I> -<DD><CODE>union</CODE> returns a list of all elements that are in <VAR>l1</VAR> or -<VAR>l2</VAR>. Duplicates between <VAR>l1</VAR> and <VAR>l2</VAR> are culled. -Duplicates within <VAR>l1</VAR> or within <VAR>l2</VAR> may or may not be -removed. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(union '(1 2 3 4) '(5 6 7 8)) - => (1 2 3 4 5 6 7 8) -(union '(0 1 2 3 4) '(3 4 5 6)) - => (5 6 0 1 2 3 4) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1292"></A> -</P> -<DL> -<DT><U>Function:</U> <B>intersection</B> <I>l1 l2</I> -<DD><CODE>intersection</CODE> returns a list of all elements that are in both -<VAR>l1</VAR> and <VAR>l2</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(intersection '(1 2 3 4) '(3 4 5 6)) - => (3 4) -(intersection '(1 2 3 4) '(5 6 7 8)) - => () -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1293"></A> -</P> -<DL> -<DT><U>Function:</U> <B>set-difference</B> <I>l1 l2</I> -<DD><CODE>set-difference</CODE> returns a list of all elements that are in -<VAR>l1</VAR> but not in <VAR>l2</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(set-difference '(1 2 3 4) '(3 4 5 6)) - => (1 2) -(set-difference '(1 2 3 4) '(1 2 3 4 5 6)) - => () -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1294"></A> -</P> -<DL> -<DT><U>Function:</U> <B>subset?</B> <I>list1 list2</I> -<DD>Returns <CODE>#t</CODE> if every element of <VAR>list1</VAR> is <CODE>eqv?</CODE> an -element of <VAR>list2</VAR>; otherwise returns <CODE>#f</CODE>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(subset? '(1 2 3 4) '(3 4 5 6)) - => #f -(subset? '(1 2 3 4) '(6 5 4 3 2 1 0)) - => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1295"></A> -</P> -<DL> -<DT><U>Function:</U> <B>member-if</B> <I>pred lst</I> -<DD><CODE>member-if</CODE> returns the list headed by the first element of -<VAR>lst</VAR> to satisfy <CODE>(<VAR>pred</VAR> <VAR>element</VAR>)</CODE>. -<CODE>Member-if</CODE> returns <CODE>#f</CODE> if <VAR>pred</VAR> returns <CODE>#f</CODE> for -every <VAR>element</VAR> in <VAR>lst</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(member-if vector? '(a 2 b 4)) - => #f -(member-if number? '(a 2 b 4)) - => (2 b 4) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1296"></A> -</P> -<DL> -<DT><U>Function:</U> <B>some</B> <I>pred lst1 lst2 <small>...</small></I> -<DD><VAR>pred</VAR> is a boolean function of as many arguments as there are list -arguments to <CODE>some</CODE> i.e., <VAR>lst</VAR> plus any optional arguments. -<VAR>pred</VAR> is applied to successive elements of the list arguments in -order. <CODE>some</CODE> returns <CODE>#t</CODE> as soon as one of these -applications returns <CODE>#t</CODE>, and is <CODE>#f</CODE> if none returns -<CODE>#t</CODE>. All the lists should have the same length. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(some odd? '(1 2 3 4)) - => #t - -(some odd? '(2 4 6 8)) - => #f - -(some > '(1 3) '(2 4)) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1297"></A> -</P> -<DL> -<DT><U>Function:</U> <B>every</B> <I>pred lst1 lst2 <small>...</small></I> -<DD><CODE>every</CODE> is analogous to <CODE>some</CODE> except it returns <CODE>#t</CODE> if -every application of <VAR>pred</VAR> is <CODE>#t</CODE> and <CODE>#f</CODE> -otherwise. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(every even? '(1 2 3 4)) - => #f - -(every even? '(2 4 6 8)) - => #t - -(every > '(2 3) '(1 4)) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1298"></A> -</P> -<DL> -<DT><U>Function:</U> <B>notany</B> <I>pred lst1 <small>...</small></I> -<DD><CODE>notany</CODE> is analogous to <CODE>some</CODE> but returns <CODE>#t</CODE> if no -application of <VAR>pred</VAR> returns <CODE>#t</CODE> or <CODE>#f</CODE> as soon as any -one does. -</DL> -<P> - -<A NAME="IDX1299"></A> -</P> -<DL> -<DT><U>Function:</U> <B>notevery</B> <I>pred lst1 <small>...</small></I> -<DD><CODE>notevery</CODE> is analogous to <CODE>some</CODE> but returns <CODE>#t</CODE> as soon -as an application of <VAR>pred</VAR> returns <CODE>#f</CODE>, and <CODE>#f</CODE> -otherwise. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(notevery even? '(1 2 3 4)) - => #t - -(notevery even? '(2 4 6 8)) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1300"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list-of??</B> <I>predicate</I> -<DD>Returns a predicate which returns true if its argument is a list every -element of which satisfies <VAR>predicate</VAR>. -<P> - -<A NAME="IDX1301"></A> -<DT><U>Function:</U> <B>list-of??</B> <I>predicate low-bound high-bound</I> -<DD><VAR>low-bound</VAR> and <VAR>high-bound</VAR> are non-negative integers. -<CODE>list-of??</CODE> returns a predicate which returns true if its argument -is a list of length between <VAR>low-bound</VAR> and <VAR>high-bound</VAR> -(inclusive); every element of which satisfies <VAR>predicate</VAR>. -</P> -<P> - -<A NAME="IDX1302"></A> -<DT><U>Function:</U> <B>list-of??</B> <I>predicate bound</I> -<DD><VAR>bound</VAR> is an integer. If <VAR>bound</VAR> is negative, <CODE>list-of??</CODE> -returns a predicate which returns true if its argument is a list of -length greater than <CODE>(- <VAR>bound</VAR>)</CODE>; every element of which -satisfies <VAR>predicate</VAR>. Otherwise, <CODE>list-of??</CODE> returns a -predicate which returns true if its argument is a list of length less -than or equal to <VAR>bound</VAR>; every element of which satisfies -<VAR>predicate</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1303"></A> -</P> -<DL> -<DT><U>Function:</U> <B>find-if</B> <I>pred lst</I> -<DD><CODE>find-if</CODE> searches for the first <VAR>element</VAR> in <VAR>lst</VAR> such -that <CODE>(<VAR>pred</VAR> <VAR>element</VAR>)</CODE> returns <CODE>#t</CODE>. If it finds -any such <VAR>element</VAR> in <VAR>lst</VAR>, <VAR>element</VAR> is returned. -Otherwise, <CODE>#f</CODE> is returned. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(find-if number? '(foo 1 bar 2)) - => 1 - -(find-if number? '(foo bar baz bang)) - => #f - -(find-if symbol? '(1 2 foo bar)) - => foo -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1304"></A> -</P> -<DL> -<DT><U>Function:</U> <B>remove</B> <I>elt lst</I> -<DD><CODE>remove</CODE> removes all occurrences of <VAR>elt</VAR> from <VAR>lst</VAR> using -<CODE>eqv?</CODE> to test for equality and returns everything that's left. -N.B.: other implementations (Chez, Scheme->C and T, at least) use -<CODE>equal?</CODE> as the equality test. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(remove 1 '(1 2 1 3 1 4 1 5)) - => (2 3 4 5) - -(remove 'foo '(bar baz bang)) - => (bar baz bang) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1305"></A> -</P> -<DL> -<DT><U>Function:</U> <B>remove-if</B> <I>pred lst</I> -<DD><CODE>remove-if</CODE> removes all <VAR>element</VAR>s from <VAR>lst</VAR> where -<CODE>(<VAR>pred</VAR> <VAR>element</VAR>)</CODE> is <CODE>#t</CODE> and returns everything -that's left. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(remove-if number? '(1 2 3 4)) - => () - -(remove-if even? '(1 2 3 4 5 6 7 8)) - => (1 3 5 7) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1306"></A> -</P> -<DL> -<DT><U>Function:</U> <B>remove-if-not</B> <I>pred lst</I> -<DD><CODE>remove-if-not</CODE> removes all <VAR>element</VAR>s from <VAR>lst</VAR> for which -<CODE>(<VAR>pred</VAR> <VAR>element</VAR>)</CODE> is <CODE>#f</CODE> and returns everything that's -left. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(remove-if-not number? '(foo bar baz)) - => () -(remove-if-not odd? '(1 2 3 4 5 6 7 8)) - => (1 3 5 7) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1307"></A> -</P> -<DL> -<DT><U>Function:</U> <B>has-duplicates?</B> <I>lst</I> -<DD>returns <CODE>#t</CODE> if 2 members of <VAR>lst</VAR> are <CODE>equal?</CODE>, <CODE>#f</CODE> -otherwise. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(has-duplicates? '(1 2 3 4)) - => #f - -(has-duplicates? '(2 4 3 4)) - => #t -</pre></td></tr></table></DL> -<P> - -The procedure <CODE>remove-duplicates</CODE> uses <CODE>member</CODE> (rather than -<CODE>memv</CODE>). -</P> -<P> - -<A NAME="IDX1308"></A> -</P> -<DL> -<DT><U>Function:</U> <B>remove-duplicates</B> <I>lst</I> -<DD>returns a copy of <VAR>lst</VAR> with its duplicate members removed. -Elements are considered duplicate if they are <CODE>equal?</CODE>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(remove-duplicates '(1 2 3 4)) - => (1 2 3 4) - -(remove-duplicates '(2 4 3 4)) - => (2 4 3) -</pre></td></tr></table></DL> -<P> - -<A NAME="Lists as sequences"></A> -<HR SIZE="6"> -<A NAME="SEC211"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC210"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC212"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.1.3 Lists as sequences </H4> -<!--docid::SEC211::--> -<P> - -<A NAME="IDX1309"></A> -</P> -<DL> -<DT><U>Function:</U> <B>position</B> <I>obj lst</I> -<DD><CODE>position</CODE> returns the 0-based position of <VAR>obj</VAR> in <VAR>lst</VAR>, -or <CODE>#f</CODE> if <VAR>obj</VAR> does not occur in <VAR>lst</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(position 'foo '(foo bar baz bang)) - => 0 -(position 'baz '(foo bar baz bang)) - => 2 -(position 'oops '(foo bar baz bang)) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1310"></A> -</P> -<DL> -<DT><U>Function:</U> <B>reduce</B> <I>p lst</I> -<DD><CODE>reduce</CODE> combines all the elements of a sequence using a binary -operation (the combination is left-associative). For example, using -<CODE>+</CODE>, one can add up all the elements. <CODE>reduce</CODE> allows you to -apply a function which accepts only two arguments to more than 2 -objects. Functional programmers usually refer to this as <EM>foldl</EM>. -<CODE>collect:reduce</CODE> (see section <A HREF="slib_7.html#SEC194">7.1.9 Collections</A>) provides a version of -<CODE>collect</CODE> generalized to collections. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(reduce + '(1 2 3 4)) - => 10 -(define (bad-sum . l) (reduce + l)) -(bad-sum 1 2 3 4) - == (reduce + (1 2 3 4)) - == (+ (+ (+ 1 2) 3) 4) -=> 10 -(bad-sum) - == (reduce + ()) - => () -(reduce string-append '("hello" "cruel" "world")) - == (string-append (string-append "hello" "cruel") "world") - => "hellocruelworld" -(reduce anything '()) - => () -(reduce anything '(x)) - => x -</pre></td></tr></table><P> - -What follows is a rather non-standard implementation of <CODE>reverse</CODE> -in terms of <CODE>reduce</CODE> and a combinator elsewhere called -<EM>C</EM>. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>;;; Contributed by Jussi Piitulainen (jpiitula @ ling.helsinki.fi) - -(define commute - (lambda (f) - (lambda (x y) - (f y x)))) - -(define reverse - (lambda (args) - (reduce-init (commute cons) '() args))) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1311"></A> -</P> -<DL> -<DT><U>Function:</U> <B>reduce-init</B> <I>p init lst</I> -<DD><CODE>reduce-init</CODE> is the same as reduce, except that it implicitly -inserts <VAR>init</VAR> at the start of the list. <CODE>reduce-init</CODE> is -preferred if you want to handle the null list, the one-element, and -lists with two or more elements consistently. It is common to use the -operator's idempotent as the initializer. Functional programmers -usually call this <EM>foldl</EM>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(define (sum . l) (reduce-init + 0 l)) -(sum 1 2 3 4) - == (reduce-init + 0 (1 2 3 4)) - == (+ (+ (+ (+ 0 1) 2) 3) 4) - => 10 -(sum) - == (reduce-init + 0 '()) - => 0 - -(reduce-init string-append "@" '("hello" "cruel" "world")) -== -(string-append (string-append (string-append "@" "hello") - "cruel") - "world") -=> "@hellocruelworld" -</pre></td></tr></table><P> - -Given a differentiation of 2 arguments, <CODE>diff</CODE>, the following will -differentiate by any number of variables. -<TABLE><tr><td> </td><td class=example><pre>(define (diff* exp . vars) - (reduce-init diff exp vars)) -</pre></td></tr></table><P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>;;; Real-world example: Insertion sort using reduce-init. - -(define (insert l item) - (if (null? l) - (list item) - (if (< (car l) item) - (cons (car l) (insert (cdr l) item)) - (cons item l)))) -(define (insertion-sort l) (reduce-init insert '() l)) - -(insertion-sort '(3 1 4 1 5) - == (reduce-init insert () (3 1 4 1 5)) - == (insert (insert (insert (insert (insert () 3) 1) 4) 1) 5) - == (insert (insert (insert (insert (3)) 1) 4) 1) 5) - == (insert (insert (insert (1 3) 4) 1) 5) - == (insert (insert (1 3 4) 1) 5) - == (insert (1 1 3 4) 5) - => (1 1 3 4 5) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1312"></A> -</P> -<DL> -<DT><U>Function:</U> <B>last</B> <I>lst n</I> -<DD><CODE>last</CODE> returns the last <VAR>n</VAR> elements of <VAR>lst</VAR>. <VAR>n</VAR> -must be a non-negative integer. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(last '(foo bar baz bang) 2) - => (baz bang) -(last '(1 2 3) 0) - => 0 -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1313"></A> -</P> -<DL> -<DT><U>Function:</U> <B>butlast</B> <I>lst n</I> -<DD><CODE>butlast</CODE> returns all but the last <VAR>n</VAR> elements of -<VAR>lst</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(butlast '(a b c d) 3) - => (a) -(butlast '(a b c d) 4) - => () -</pre></td></tr></table></DL> -<P> - -<CODE>last</CODE> and <CODE>butlast</CODE> split a list into two parts when given -identical arugments. -<TABLE><tr><td> </td><td class=example><pre>(last '(a b c d e) 2) - => (d e) -(butlast '(a b c d e) 2) - => (a b c) -</pre></td></tr></table><P> - -<A NAME="IDX1314"></A> -</P> -<DL> -<DT><U>Function:</U> <B>nthcdr</B> <I>n lst</I> -<DD><CODE>nthcdr</CODE> takes <VAR>n</VAR> <CODE>cdr</CODE>s of <VAR>lst</VAR> and returns the -result. Thus <CODE>(nthcdr 3 <VAR>lst</VAR>)</CODE> == <CODE>(cdddr -<VAR>lst</VAR>)</CODE> -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(nthcdr 2 '(a b c d)) - => (c d) -(nthcdr 0 '(a b c d)) - => (a b c d) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1315"></A> -</P> -<DL> -<DT><U>Function:</U> <B>butnthcdr</B> <I>n lst</I> -<DD><CODE>butnthcdr</CODE> returns all but the nthcdr <VAR>n</VAR> elements of -<VAR>lst</VAR>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(butnthcdr 3 '(a b c d)) - => (a b c) -(butnthcdr 4 '(a b c d)) - => (a b c d) -</pre></td></tr></table></DL> -<P> - -<CODE>nthcdr</CODE> and <CODE>butnthcdr</CODE> split a list into two parts when -given identical arugments. -<TABLE><tr><td> </td><td class=example><pre>(nthcdr 2 '(a b c d e)) - => (c d e) -(butnthcdr 2 '(a b c d e)) - => (a b) -</pre></td></tr></table><P> - -<A NAME="Destructive list operations"></A> -<HR SIZE="6"> -<A NAME="SEC212"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC211"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC213"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.1.4 Destructive list operations </H4> -<!--docid::SEC212::--> -<P> - -These procedures may mutate the list they operate on, but any such -mutation is undefined. -</P> -<P> - -<A NAME="IDX1316"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>nconc</B> <I>args</I> -<DD><CODE>nconc</CODE> destructively concatenates its arguments. (Compare this -with <CODE>append</CODE>, which copies arguments rather than destroying them.) -Sometimes called <CODE>append!</CODE> (see section <A HREF="slib_7.html#SEC239">7.4.4 Rev2 Procedures</A>). -<P> - -Example: You want to find the subsets of a set. Here's the obvious way: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define (subsets set) - (if (null? set) - '(()) - (append (map (lambda (sub) (cons (car set) sub)) - (subsets (cdr set))) - (subsets (cdr set))))) -</pre></td></tr></table>But that does way more consing than you need. Instead, you could -replace the <CODE>append</CODE> with <CODE>nconc</CODE>, since you don't have any -need for all the intermediate results. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(define x '(a b c)) -(define y '(d e f)) -(nconc x y) - => (a b c d e f) -x - => (a b c d e f) -</pre></td></tr></table><P> - -<CODE>nconc</CODE> is the same as <CODE>append!</CODE> in `<TT>sc2.scm</TT>'. -</P> -</DL> -<P> - -<A NAME="IDX1317"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>nreverse</B> <I>lst</I> -<DD><CODE>nreverse</CODE> reverses the order of elements in <VAR>lst</VAR> by mutating -<CODE>cdr</CODE>s of the list. Sometimes called <CODE>reverse!</CODE>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(define foo '(a b c)) -(nreverse foo) - => (c b a) -foo - => (a) -</pre></td></tr></table><P> - -Some people have been confused about how to use <CODE>nreverse</CODE>, -thinking that it doesn't return a value. It needs to be pointed out -that -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(set! lst (nreverse lst)) -</pre></td></tr></table>is the proper usage, not -<TABLE><tr><td> </td><td class=example><pre>(nreverse lst) -</pre></td></tr></table>The example should suffice to show why this is the case. -</DL> -<P> - -<A NAME="IDX1318"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>delete</B> <I>elt lst</I> -<DD><A NAME="IDX1319"></A> -<DT><U>Procedure:</U> <B>delete-if</B> <I>pred lst</I> -<DD><A NAME="IDX1320"></A> -<DT><U>Procedure:</U> <B>delete-if-not</B> <I>pred lst</I> -<DD>Destructive versions of <CODE>remove</CODE> <CODE>remove-if</CODE>, and -<CODE>remove-if-not</CODE>. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(define lst (list 'foo 'bar 'baz 'bang)) -(delete 'foo lst) - => (bar baz bang) -lst - => (foo bar baz bang) - -(define lst (list 1 2 3 4 5 6 7 8 9)) -(delete-if odd? lst) - => (2 4 6 8) -lst - => (1 2 4 6 8) -</pre></td></tr></table><P> - -Some people have been confused about how to use <CODE>delete</CODE>, -<CODE>delete-if</CODE>, and <CODE>delete-if</CODE>, thinking that they don't return -a value. It needs to be pointed out that -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(set! lst (delete el lst)) -</pre></td></tr></table>is the proper usage, not -<TABLE><tr><td> </td><td class=example><pre>(delete el lst) -</pre></td></tr></table>The examples should suffice to show why this is the case. -</DL> -<P> - -<A NAME="Non-List functions"></A> -<HR SIZE="6"> -<A NAME="SEC213"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC212"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC214"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC208"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.1.5 Non-List functions </H4> -<!--docid::SEC213::--> -<P> - -<A NAME="IDX1321"></A> -</P> -<DL> -<DT><U>Function:</U> <B>and?</B> <I>arg1 <small>...</small></I> -<DD><CODE>and?</CODE> checks to see if all its arguments are true. If they are, -<CODE>and?</CODE> returns <CODE>#t</CODE>, otherwise, <CODE>#f</CODE>. (In contrast to -<CODE>and</CODE>, this is a function, so all arguments are always evaluated -and in an unspecified order.) -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(and? 1 2 3) - => #t -(and #f 1 2) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1322"></A> -</P> -<DL> -<DT><U>Function:</U> <B>or?</B> <I>arg1 <small>...</small></I> -<DD><CODE>or?</CODE> checks to see if any of its arguments are true. If any is -true, <CODE>or?</CODE> returns <CODE>#t</CODE>, and <CODE>#f</CODE> otherwise. (To -<CODE>or</CODE> as <CODE>and?</CODE> is to <CODE>and</CODE>.) -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(or? 1 2 #f) - => #t -(or? #f #f #f) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1323"></A> -</P> -<DL> -<DT><U>Function:</U> <B>atom?</B> <I>object</I> -<DD>Returns <CODE>#t</CODE> if <VAR>object</VAR> is not a pair and <CODE>#f</CODE> if it is -pair. (Called <CODE>atom</CODE> in Common LISP.) -<TABLE><tr><td> </td><td class=example><pre>(atom? 1) - => #t -(atom? '(1 2)) - => #f -(atom? #(1 2)) ; dubious! - => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="Tree Operations"></A> -<HR SIZE="6"> -<A NAME="SEC214"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC213"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC215"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.2 Tree operations </H3> -<!--docid::SEC214::--> -<P> - -<CODE>(require 'tree)</CODE> -<A NAME="IDX1324"></A> -</P> -<P> - -These are operations that treat lists a representations of trees. -</P> -<P> - -<A NAME="IDX1325"></A> -</P> -<DL> -<DT><U>Function:</U> <B>subst</B> <I>new old tree</I> -<DD><A NAME="IDX1326"></A> -<DT><U>Function:</U> <B>substq</B> <I>new old tree</I> -<DD><A NAME="IDX1327"></A> -<DT><U>Function:</U> <B>substv</B> <I>new old tree</I> -<DD><P> - -<A NAME="IDX1328"></A> -<DT><U>Function:</U> <B>subst</B> <I>new old tree equ?</I> -<DD><CODE>subst</CODE> makes a copy of <VAR>tree</VAR>, substituting <VAR>new</VAR> for -every subtree or leaf of <VAR>tree</VAR> which is <CODE>equal?</CODE> to <VAR>old</VAR> -and returns a modified tree. The original <VAR>tree</VAR> is unchanged, but -may share parts with the result. -</P> -<P> - -<CODE>substq</CODE> and <CODE>substv</CODE> are similar, but test against <VAR>old</VAR> -using <CODE>eq?</CODE> and <CODE>eqv?</CODE> respectively. If <CODE>subst</CODE> is -called with a fourth argument, <VAR>equ?</VAR> is the equality predicate. -</P> -<P> - -Examples: -<TABLE><tr><td> </td><td class=example><pre>(substq 'tempest 'hurricane '(shakespeare wrote (the hurricane))) - => (shakespeare wrote (the tempest)) -(substq 'foo '() '(shakespeare wrote (twelfth night))) - => (shakespeare wrote (twelfth night . foo) . foo) -(subst '(a . cons) '(old . pair) - '((old . spice) ((old . shoes) old . pair) (old . pair))) - => ((old . spice) ((old . shoes) a . cons) (a . cons)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1329"></A> -</P> -<DL> -<DT><U>Function:</U> <B>copy-tree</B> <I>tree</I> -<DD><P> - -Makes a copy of the nested list structure <VAR>tree</VAR> using new pairs and -returns it. All levels are copied, so that none of the pairs in the -tree are <CODE>eq?</CODE> to the original ones -- only the leaves are. -</P> -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(define bar '(bar)) -(copy-tree (list bar 'foo)) - => ((bar) foo) -(eq? bar (car (copy-tree (list bar 'foo)))) - => #f -</pre></td></tr></table></DL> -<P> - -<A NAME="Chapter Ordering"></A> -<HR SIZE="6"> -<A NAME="SEC215"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC214"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC216"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.3 Chapter Ordering </H3> -<!--docid::SEC215::--> -<P> - -<CODE>(require 'chapter-order)</CODE> -<A NAME="IDX1330"></A> -</P> -<P> - -The `<SAMP>chap:</SAMP>' functions deal with strings which are ordered like -chapter numbers (or letters) in a book. Each section of the string -consists of consecutive numeric or consecutive aphabetic characters of -like case. -</P> -<P> - -<A NAME="IDX1331"></A> -</P> -<DL> -<DT><U>Function:</U> <B>chap:string<?</B> <I>string1 string2</I> -<DD><P> - -Returns #t if the first non-matching run of alphabetic upper-case or -the first non-matching run of alphabetic lower-case or the first -non-matching run of numeric characters of <VAR>string1</VAR> is -<CODE>string<?</CODE> than the corresponding non-matching run of -characters of <VAR>string2</VAR>. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(chap:string<? "a.9" "a.10") => #t -(chap:string<? "4c" "4aa") => #t -(chap:string<? "Revised^{3.99}" "Revised^{4}") => #t -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1332"></A> -</P> -<DL> -<DT><U>Function:</U> <B>chap:string>?</B> <I>string1 string2</I> -<DD><A NAME="IDX1333"></A> -<DT><U>Function:</U> <B>chap:string<=?</B> <I>string1 string2</I> -<DD><A NAME="IDX1334"></A> -<DT><U>Function:</U> <B>chap:string>=?</B> <I>string1 string2</I> -<DD><P> - -Implement the corresponding chapter-order predicates. -</P> -</DL> -<P> - -<A NAME="IDX1335"></A> -</P> -<DL> -<DT><U>Function:</U> <B>chap:next-string</B> <I>string</I> -<DD><P> - -Returns the next string in the <EM>chapter order</EM>. If <VAR>string</VAR> -has no alphabetic or numeric characters, -<CODE>(string-append <VAR>string</VAR> "0")</CODE> is returnd. The argument to -chap:next-string will always be <CODE>chap:string<?</CODE> than the result. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(chap:next-string "a.9") => "a.10" -(chap:next-string "4c") => "4d" -(chap:next-string "4z") => "4aa" -(chap:next-string "Revised^{4}") => "Revised^{5}" - -</pre></td></tr></table></DL> -<P> - -<A NAME="Sorting"></A> -<HR SIZE="6"> -<A NAME="SEC216"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC215"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC217"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.4 Sorting </H3> -<!--docid::SEC216::--> -<P> - -<CODE>(require 'sort)</CODE> -<A NAME="IDX1336"></A> -</P> -<P> - -Many Scheme systems provide some kind of sorting functions. They do -not, however, always provide the <EM>same</EM> sorting functions, and -those that I have had the opportunity to test provided inefficient ones -(a common blunder is to use quicksort which does not perform well). -</P> -<P> - -Because <CODE>sort</CODE> and <CODE>sort!</CODE> are not in the standard, there is -very little agreement about what these functions look like. For -example, Dybvig says that Chez Scheme provides -<TABLE><tr><td> </td><td class=example><pre>(merge predicate list1 list2) -(merge! predicate list1 list2) -(sort predicate list) -(sort! predicate list) -</pre></td></tr></table>while MIT Scheme 7.1, following Common LISP, offers unstable -<TABLE><tr><td> </td><td class=example><pre>(sort list predicate) -</pre></td></tr></table>TI PC Scheme offers -<TABLE><tr><td> </td><td class=example><pre>(sort! list/vector predicate?) -</pre></td></tr></table>and Elk offers -<TABLE><tr><td> </td><td class=example><pre>(sort list/vector predicate?) -(sort! list/vector predicate?) -</pre></td></tr></table><P> - -Here is a comprehensive catalogue of the variations I have found. -</P> -<P> - -<OL> -<LI> -Both <CODE>sort</CODE> and <CODE>sort!</CODE> may be provided. -<LI> -<CODE>sort</CODE> may be provided without <CODE>sort!</CODE>. -<LI> -<CODE>sort!</CODE> may be provided without <CODE>sort</CODE>. -<LI> -Neither may be provided. -<LI> -The sequence argument may be either a list or a vector. -<LI> -The sequence argument may only be a list. -<LI> -The sequence argument may only be a vector. -<LI> -The comparison function may be expected to behave like <CODE><</CODE>. -<LI> -The comparison function may be expected to behave like <CODE><=</CODE>. -<LI> -The interface may be <CODE>(sort predicate? sequence)</CODE>. -<LI> -The interface may be <CODE>(sort sequence predicate?)</CODE>. -<LI> -The interface may be <CODE>(sort sequence &optional (predicate? <))</CODE>. -<LI> -The sort may be stable. -<LI> -The sort may be unstable. -</OL> -<P> - -All of this variation really does not help anybody. A nice simple merge -sort is both stable and fast (quite a lot faster than <EM>quick</EM> sort). -</P> -<P> - -I am providing this source code with no restrictions at all on its use -(but please retain D.H.D.Warren's credit for the original idea). You -may have to rename some of these functions in order to use them in a -system which already provides incompatible or inferior sorts. For each -of the functions, only the top-level define needs to be edited to do -that. -</P> -<P> - -I could have given these functions names which would not clash with any -Scheme that I know of, but I would like to encourage implementors to -converge on a single interface, and this may serve as a hint. The -argument order for all functions has been chosen to be as close to -Common LISP as made sense, in order to avoid NIH-itis. -</P> -<P> - -Each of the five functions has a required <EM>last</EM> parameter which is -a comparison function. A comparison function <CODE>f</CODE> is a function of -2 arguments which acts like <CODE><</CODE>. For example, -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(not (f x x)) -(and (f x y) (f y z)) == (f x z) -</pre></td></tr></table><P> - -The standard functions <CODE><</CODE>, <CODE>></CODE>, <CODE>char<?</CODE>, <CODE>char>?</CODE>, -<CODE>char-ci<?</CODE>, <CODE>char-ci>?</CODE>, <CODE>string<?</CODE>, <CODE>string>?</CODE>, -<CODE>string-ci<?</CODE>, and <CODE>string-ci>?</CODE> are suitable for use as -comparison functions. Think of <CODE>(less? x y)</CODE> as saying when -<CODE>x</CODE> must <EM>not</EM> precede <CODE>y</CODE>. -</P> -<P> - -<A NAME="IDX1337"></A> -</P> -<DL> -<DT><U>Function:</U> <B>sorted?</B> <I>sequence less?</I> -<DD>Returns <CODE>#t</CODE> when the sequence argument is in non-decreasing order -according to <VAR>less?</VAR> (that is, there is no adjacent pair <CODE><small>...</small> x -y <small>...</small></CODE> for which <CODE>(less? y x)</CODE>). -<P> - -Returns <CODE>#f</CODE> when the sequence contains at least one out-of-order -pair. It is an error if the sequence is not a list, vector, or -string. -</P> -</DL> -<P> - -<A NAME="IDX1338"></A> -</P> -<DL> -<DT><U>Function:</U> <B>merge</B> <I>list1 list2 less?</I> -<DD>This merges two lists, producing a completely new list as result. I -gave serious consideration to producing a Common-LISP-compatible -version. However, Common LISP's <CODE>sort</CODE> is our <CODE>sort!</CODE> (well, -in fact Common LISP's <CODE>stable-sort</CODE> is our <CODE>sort!</CODE>, merge sort -is <EM>fast</EM> as well as stable!) so adapting CL code to Scheme takes a -bit of work anyway. I did, however, appeal to CL to determine the -<EM>order</EM> of the arguments. -</DL> -<P> - -<A NAME="IDX1339"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>merge!</B> <I>list1 list2 less?</I> -<DD>Merges two lists, re-using the pairs of <VAR>list1</VAR> and <VAR>list2</VAR> to -build the result. If the code is compiled, and <VAR>less?</VAR> constructs -no new pairs, no pairs at all will be allocated. The first pair of the -result will be either the first pair of <VAR>list1</VAR> or the first pair of -<VAR>list2</VAR>, but you can't predict which. -<P> - -The code of <CODE>merge</CODE> and <CODE>merge!</CODE> could have been quite a bit -simpler, but they have been coded to reduce the amount of work done per -iteration. (For example, we only have one <CODE>null?</CODE> test per -iteration.) -</P> -<P> - -</P> -</DL> -<P> - -<A NAME="IDX1340"></A> -</P> -<DL> -<DT><U>Function:</U> <B>sort</B> <I>sequence less?</I> -<DD>Accepts either a list, vector, or string; and returns a new sequence -which is sorted. The new sequence is the same type as the input. -Always <CODE>(sorted? (sort sequence less?) less?)</CODE>. The original -sequence is not altered in any way. The new sequence shares its -<EM>elements</EM> with the old one; no elements are copied. -</DL> -<P> - -<A NAME="IDX1341"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>sort!</B> <I>sequence less?</I> -<DD>Returns its sorted result in the original boxes. If the original -sequence is a list, no new storage is allocated at all. If the -original sequence is a vector or string, the sorted elements are put -back in the same vector or string. -<P> - -Some people have been confused about how to use <CODE>sort!</CODE>, thinking -that it doesn't return a value. It needs to be pointed out that -<TABLE><tr><td> </td><td class=example><pre>(set! slist (sort! slist <)) -</pre></td></tr></table>is the proper usage, not -<TABLE><tr><td> </td><td class=example><pre>(sort! slist <) -</pre></td></tr></table></DL> -<P> - -Note that these functions do <EM>not</EM> accept a CL-style `<SAMP>:key</SAMP>' -argument. A simple device for obtaining the same expressiveness is to -define -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define (keyed less? key) - (lambda (x y) (less? (key x) (key y)))) -</pre></td></tr></table>and then, when you would have written -<TABLE><tr><td> </td><td class=example><pre>(sort a-sequence #'my-less :key #'my-key) -</pre></td></tr></table>in Common LISP, just write -<TABLE><tr><td> </td><td class=example><pre>(sort! a-sequence (keyed my-less? my-key)) -</pre></td></tr></table>in Scheme. -<P> - -<A NAME="Topological Sort"></A> -<HR SIZE="6"> -<A NAME="SEC217"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC216"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC218"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.5 Topological Sort </H3> -<!--docid::SEC217::--> -<P> - -<CODE>(require 'topological-sort)</CODE> or <CODE>(require 'tsort)</CODE> -<A NAME="IDX1342"></A> -<A NAME="IDX1343"></A> -</P> -<P> - -The algorithm is inspired by Cormen, Leiserson and Rivest (1990) -<CITE>Introduction to Algorithms</CITE>, chapter 23. -</P> -<P> - -<A NAME="IDX1344"></A> -</P> -<DL> -<DT><U>Function:</U> <B>tsort</B> <I>dag pred</I> -<DD><P> - -<A NAME="IDX1345"></A> -<DT><U>Function:</U> <B>topological-sort</B> <I>dag pred</I> -<DD>where -</P> -<DL COMPACT> -<DT><VAR>dag</VAR> -<DD>is a list of sublists. The car of each sublist is a vertex. The cdr is -the adjacency list of that vertex, i.e. a list of all vertices to which -there exists an edge from the car vertex. -<DT><VAR>pred</VAR> -<DD>is one of <CODE>eq?</CODE>, <CODE>eqv?</CODE>, <CODE>equal?</CODE>, <CODE>=</CODE>, -<CODE>char=?</CODE>, <CODE>char-ci=?</CODE>, <CODE>string=?</CODE>, or <CODE>string-ci=?</CODE>. -</DL> -<P> - -Sort the directed acyclic graph <VAR>dag</VAR> so that for every edge from -vertex <VAR>u</VAR> to <VAR>v</VAR>, <VAR>u</VAR> will come before <VAR>v</VAR> in the -resulting list of vertices. -</P> -<P> - -Time complexity: O (|V| + |E|) -</P> -<P> - -Example (from Cormen): -<BLOCKQUOTE> -Prof. Bumstead topologically sorts his clothing when getting -dressed. The first argument to <CODE>tsort</CODE> describes which -garments he needs to put on before others. (For example, -Prof Bumstead needs to put on his shirt before he puts on his -tie or his belt.) <CODE>tsort</CODE> gives the correct order of dressing: -</BLOCKQUOTE> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(require 'tsort) -<A NAME="IDX1346"></A>(tsort '((shirt tie belt) - (tie jacket) - (belt jacket) - (watch) - (pants shoes belt) - (undershorts pants shoes) - (socks shoes)) - eq?) -=> -(socks undershorts pants shoes watch shirt belt tie jacket) -</pre></td></tr></table></DL> -<P> - -<A NAME="Hashing"></A> -<HR SIZE="6"> -<A NAME="SEC218"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC217"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC219"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.6 Hashing </H3> -<!--docid::SEC218::--> -<P> - -<CODE>(require 'hash)</CODE> -<A NAME="IDX1347"></A> -</P> -<P> - -These hashing functions are for use in quickly classifying objects. -Hash tables use these functions. -</P> -<P> - -<A NAME="IDX1348"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hashq</B> <I>obj k</I> -<DD><A NAME="IDX1349"></A> -<DT><U>Function:</U> <B>hashv</B> <I>obj k</I> -<DD><A NAME="IDX1350"></A> -<DT><U>Function:</U> <B>hash</B> <I>obj k</I> -<DD>Returns an exact non-negative integer less than <VAR>k</VAR>. For each -non-negative integer less than <VAR>k</VAR> there are arguments <VAR>obj</VAR> for -which the hashing functions applied to <VAR>obj</VAR> and <VAR>k</VAR> returns -that integer. -<P> - -For <CODE>hashq</CODE>, <CODE>(eq? obj1 obj2)</CODE> implies <CODE>(= (hashq obj1 k) -(hashq obj2))</CODE>. -</P> -<P> - -For <CODE>hashv</CODE>, <CODE>(eqv? obj1 obj2)</CODE> implies <CODE>(= (hashv obj1 k) -(hashv obj2))</CODE>. -</P> -<P> - -For <CODE>hash</CODE>, <CODE>(equal? obj1 obj2)</CODE> implies <CODE>(= (hash obj1 k) -(hash obj2))</CODE>. -</P> -<P> - -<CODE>hash</CODE>, <CODE>hashv</CODE>, and <CODE>hashq</CODE> return in time bounded by a -constant. Notice that items having the same <CODE>hash</CODE> implies the -items have the same <CODE>hashv</CODE> implies the items have the same -<CODE>hashq</CODE>. -</P> -</DL> -<P> - -<A NAME="Space-Filling Curves"></A> -<HR SIZE="6"> -<A NAME="SEC219"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC218"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC220"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.7 Space-Filling Curves </H3> -<!--docid::SEC219::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC220">7.2.7.1 Peano-Hilbert Space-Filling Curve</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC221">7.2.7.2 Sierpinski Curve</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -</TABLE> -<P> - -<A NAME="Peano-Hilbert Space-Filling Curve"></A> -<HR SIZE="6"> -<A NAME="SEC220"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC219"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC221"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC219"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.7.1 Peano-Hilbert Space-Filling Curve </H4> -<!--docid::SEC220::--> -<P> - -<CODE>(require 'hilbert-fill)</CODE> -<A NAME="IDX1351"></A> -</P> -<P> - -<A NAME="IDX1352"></A> -<A NAME="IDX1353"></A> -<A NAME="IDX1354"></A> -The <EM>Peano-Hilbert Space-Filling Curve</EM> is a one-to-one mapping -<A NAME="IDX1355"></A> -between a unit line segment and an <VAR>n</VAR>-dimensional unit cube. -</P> -<P> - -The integer procedures map the non-negative integers to an -arbitrarily large <VAR>n</VAR>-dimensional cube with its corner at the -origin and all coordinates are non-negative. -</P> -<P> - -For any exact nonnegative integers <VAR>scalar</VAR> and <VAR>rank</VAR>, -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(= <VAR>scalar</VAR> (hilbert-coordinates->integer - (integer->hilbert-coordinates <VAR>scalar</VAR> <VAR>rank</VAR>))) - => #t -</pre></td></tr></table><P> - -<A NAME="IDX1356"></A> -</P> -<DL> -<DT><U>Function:</U> <B>integer->hilbert-coordinates</B> <I>scalar rank</I> -<DD><P> - -Returns a list of <VAR>rank</VAR> integer coordinates corresponding to exact -non-negative integer <VAR>scalar</VAR>. The lists returned by <CODE>integer->hilbert-coordinates</CODE> for <VAR>scalar</VAR> arguments -0 and 1 will differ in the first element. -</P> -</DL> -<P> - -<A NAME="IDX1357"></A> -</P> -<DL> -<DT><U>Function:</U> <B>hilbert-coordinates->integer</B> <I>coords</I> -<DD><P> - -Returns an exact non-negative integer corresponding to <VAR>coords</VAR>, a list -of non-negative integer coordinates. -</P> -</DL> -<P> - -<A NAME="Sierpinski Curve"></A> -<HR SIZE="6"> -<A NAME="SEC221"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC220"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC222"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC219"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.2.7.2 Sierpinski Curve </H4> -<!--docid::SEC221::--> -<P> - -<CODE>(require 'sierpinski)</CODE> -<A NAME="IDX1358"></A> -</P> -<P> - -<A NAME="IDX1359"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-sierpinski-indexer</B> <I>max-coordinate</I> -<DD>Returns a procedure (eg hash-function) of 2 numeric arguments which -preserves <EM>nearness</EM> in its mapping from NxN to N. -<P> - -<VAR>max-coordinate</VAR> is the maximum coordinate (a positive integer) of a -population of points. The returned procedures is a function that takes -the x and y coordinates of a point, (non-negative integers) and returns -an integer corresponding to the relative position of that point along a -Sierpinski curve. (You can think of this as computing a (pseudo-) -inverse of the Sierpinski spacefilling curve.) -</P> -<P> - -Example use: Make an indexer (hash-function) for integer points lying in -square of integer grid points [0,99]x[0,99]: -<TABLE><tr><td> </td><td class=example><pre>(define space-key (make-sierpinski-indexer 100)) -</pre></td></tr></table>Now let's compute the index of some points: -<TABLE><tr><td> </td><td class=example><pre>(space-key 24 78) => 9206 -(space-key 23 80) => 9172 -</pre></td></tr></table><P> - -Note that locations (24, 78) and (23, 80) are near in index and -therefore, because the Sierpinski spacefilling curve is continuous, we -know they must also be near in the plane. Nearness in the plane does -not, however, necessarily correspond to nearness in index, although it -<EM>tends</EM> to be so. -</P> -<P> - -Example applications: -<UL> - -<LI> -Sort points by Sierpinski index to get heuristic solution to -<EM>travelling salesman problem</EM>. For details of performance, -see L. Platzman and J. Bartholdi, "Spacefilling curves and the -Euclidean travelling salesman problem", JACM 36(4):719--737 -(October 1989) and references therein. -<P> - -</P> -<LI> -Use Sierpinski index as key by which to store 2-dimensional data -in a 1-dimensional data structure (such as a table). Then -locations that are near each other in 2-d space will tend to -be near each other in 1-d data structure; and locations that -are near in 1-d data structure will be near in 2-d space. This -can significantly speed retrieval from secondary storage because -contiguous regions in the plane will tend to correspond to -contiguous regions in secondary storage. (This is a standard -technique for managing CAD/CAM or geographic data.) -<P> - -</UL> -</DL> -<P> - -<A NAME="Soundex"></A> -<HR SIZE="6"> -<A NAME="SEC222"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC221"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC223"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.8 Soundex </H3> -<!--docid::SEC222::--> -<P> - -<CODE>(require 'soundex)</CODE> -<A NAME="IDX1360"></A> -</P> -<P> - -<A NAME="IDX1361"></A> -</P> -<DL> -<DT><U>Function:</U> <B>soundex</B> <I>name</I> -<DD>Computes the <EM>soundex</EM> hash of <VAR>name</VAR>. Returns a string of an -initial letter and up to three digits between 0 and 6. Soundex -supposedly has the property that names that sound similar in normal -English pronunciation tend to map to the same key. -<P> - -Soundex was a classic algorithm used for manual filing of personal -records before the advent of computers. It performs adequately for -English names but has trouble with other languages. -</P> -<P> - -See Knuth, Vol. 3 <CITE>Sorting and searching</CITE>, pp 391--2 -</P> -<P> - -To manage unusual inputs, <CODE>soundex</CODE> omits all non-alphabetic -characters. Consequently, in this implementation: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(soundex <string of blanks>) => "" -(soundex "") => "" -</pre></td></tr></table><P> - -Examples from Knuth: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(map soundex '("Euler" "Gauss" "Hilbert" "Knuth" - "Lloyd" "Lukasiewicz")) - => ("E460" "G200" "H416" "K530" "L300" "L222") - -(map soundex '("Ellery" "Ghosh" "Heilbronn" "Kant" - "Ladd" "Lissajous")) - => ("E460" "G200" "H416" "K530" "L300" "L222") -</pre></td></tr></table><P> - -Some cases in which the algorithm fails (Knuth): -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(map soundex '("Rogers" "Rodgers")) => ("R262" "R326") - -(map soundex '("Sinclair" "St. Clair")) => ("S524" "S324") - -(map soundex '("Tchebysheff" "Chebyshev")) => ("T212" "C121") -</pre></td></tr></table></DL> -<P> - -<A NAME="String Search"></A> -<HR SIZE="6"> -<A NAME="SEC223"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC222"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC224"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.9 String Search </H3> -<!--docid::SEC223::--> -<P> - -<CODE>(require 'string-search)</CODE> -<A NAME="IDX1362"></A> -</P> -<P> - -<A NAME="IDX1363"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>string-index</B> <I>string char</I> -<DD><A NAME="IDX1364"></A> -<DT><U>Procedure:</U> <B>string-index-ci</B> <I>string char</I> -<DD>Returns the index of the first occurence of <VAR>char</VAR> within -<VAR>string</VAR>, or <CODE>#f</CODE> if the <VAR>string</VAR> does not contain a -character <VAR>char</VAR>. -</DL> -<P> - -<A NAME="IDX1365"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>string-reverse-index</B> <I>string char</I> -<DD><A NAME="IDX1366"></A> -<DT><U>Procedure:</U> <B>string-reverse-index-ci</B> <I>string char</I> -<DD>Returns the index of the last occurence of <VAR>char</VAR> within -<VAR>string</VAR>, or <CODE>#f</CODE> if the <VAR>string</VAR> does not contain a -character <VAR>char</VAR>. -</DL> -<P> - -<A NAME="IDX1367"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>substring?</B> <I>pattern string</I> -<DD><A NAME="IDX1368"></A> -<DT><U>Procedure:</U> <B>substring-ci?</B> <I>pattern string</I> -<DD>Searches <VAR>string</VAR> to see if some substring of <VAR>string</VAR> is equal -to <VAR>pattern</VAR>. <CODE>substring?</CODE> returns the index of the first -character of the first substring of <VAR>string</VAR> that is equal to -<VAR>pattern</VAR>; or <CODE>#f</CODE> if <VAR>string</VAR> does not contain -<VAR>pattern</VAR>. -<P> - -<TABLE><tr><td> </td><td class=example><pre>(substring? "rat" "pirate") => 2 -(substring? "rat" "outrage") => #f -(substring? "" any-string) => 0 -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1369"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>find-string-from-port?</B> <I>str in-port max-no-chars</I> -<DD>Looks for a string <VAR>str</VAR> within the first <VAR>max-no-chars</VAR> chars -of the input port <VAR>in-port</VAR>. -<P> - -<A NAME="IDX1370"></A> -<DT><U>Procedure:</U> <B>find-string-from-port?</B> <I>str in-port</I> -<DD>When called with two arguments, the search span is limited by the end of -the input stream. -</P> -<P> - -<A NAME="IDX1371"></A> -<DT><U>Procedure:</U> <B>find-string-from-port?</B> <I>str in-port char</I> -<DD>Searches up to the first occurrence of character <VAR>char</VAR> in -<VAR>str</VAR>. -</P> -<P> - -<A NAME="IDX1372"></A> -<DT><U>Procedure:</U> <B>find-string-from-port?</B> <I>str in-port proc</I> -<DD>Searches up to the first occurrence of the procedure <VAR>proc</VAR> -returning non-false when called with a character (from <VAR>in-port</VAR>) -argument. -</P> -<P> - -When the <VAR>str</VAR> is found, <CODE>find-string-from-port?</CODE> returns the -number of characters it has read from the port, and the port is set to -read the first char after that (that is, after the <VAR>str</VAR>) The -function returns <CODE>#f</CODE> when the <VAR>str</VAR> isn't found. -</P> -<P> - -<CODE>find-string-from-port?</CODE> reads the port <EM>strictly</EM> -sequentially, and does not perform any buffering. So -<CODE>find-string-from-port?</CODE> can be used even if the <VAR>in-port</VAR> is -open to a pipe or other communication channel. -</P> -</DL> -<P> - -<A NAME="IDX1373"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string-subst</B> <I>txt old1 new1 <small>...</small></I> -<DD>Returns a copy of string <VAR>txt</VAR> with all occurrences of string -<VAR>old1</VAR> in <VAR>txt</VAR> replaced with <VAR>new1</VAR>; then <VAR>old2</VAR> -replaced with <VAR>new2</VAR> <small>...</small>. Matches are found from the left. -Matches do not overlap. -</DL> -<P> - -<A NAME="IDX1374"></A> -</P> -<DL> -<DT><U>Function:</U> <B>count-newlines</B> <I>str</I> -<DD>Returns the number of `<SAMP>#\newline</SAMP>' characters in string <VAR>str</VAR>. -</DL> -<P> - -<A NAME="Sequence Comparison"></A> -<HR SIZE="6"> -<A NAME="SEC224"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC223"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC207"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.2.10 Sequence Comparison </H3> -<!--docid::SEC224::--> -<P> - -<CODE>(require 'diff)</CODE> -<A NAME="IDX1375"></A> -<A NAME="IDX1376"></A> -</P> -<P> - -<CODE>diff:edit-length</CODE> implements the algorithm: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>S. Wu, E. Myers, U. Manber, and W. Miller, - "An O(NP) Sequence Comparison Algorithm," - Information Processing Letters 35, 6 (1990), 317-323. - <A HREF="http://www.cs.arizona.edu/people/gene/vita.html">http://www.cs.arizona.edu/people/gene/vita.html</A> -</pre></td></tr></table>S. Wu, <A HREF="http://www.cs.arizona.edu/people/gene/vita.html"> -E. Myers,</A> U. Manber, and W. Miller, -<A HREF="http://www.cs.arizona.edu/people/gene/PAPERS/np_diff.ps"> -"An O(NP) Sequence Comparison Algorithm,"</A> -Information Processing Letters 35, 6 (1990), 317-323. -<P> - -The values returned by <CODE>diff:edit-length</CODE> can be used to gauge -the degree of match between two sequences. -</P> -<P> - -Surprisingly, "An O(NP) Sequence Comparison Algorithm" does not -derive the edit sequence; only the sequence length. Developing this -linear-space sub-quadratic-time algorithm for computing the edit -sequence required hundreds of hours of work. I have submitted a -paper describing the algorithm to the Journal of Computational -Biology. -</P> -<P> - -If the items being sequenced are text lines, then the computed -edit-list is equivalent to the output of the <EM>diff</EM> utility -<A NAME="IDX1377"></A> -program. If the items being sequenced are words, then it is like the -lesser known <EM>spiff</EM> program. -<A NAME="IDX1378"></A> -</P> -<P> - -<A NAME="IDX1379"></A> -</P> -<DL> -<DT><U>Function:</U> <B>diff:longest-common-subsequence</B> <I>array1 array2 =? p-lim</I> -<DD><P> - -<A NAME="IDX1380"></A> -<DT><U>Function:</U> <B>diff:longest-common-subsequence</B> <I>array1 array2 =?</I> -<DD><VAR>array1</VAR> and <VAR>array2</VAR> are one-dimensional arrays. The procedure <VAR>=?</VAR> is used -to compare sequence tokens for equality. -</P> -<P> - -The non-negative integer <VAR>p-lim</VAR>, if provided, is maximum number of -deletions of the shorter sequence to allow. <CODE>diff:longest-common-subsequence</CODE> will return <CODE>#f</CODE> -if more deletions would be necessary. -</P> -<P> - -<CODE>diff:longest-common-subsequence</CODE> returns a one-dimensional array of length <CODE>(quotient (- (+ -len1 len2) (diff:edit-length <VAR>array1</VAR> <VAR>array2</VAR>)) 2)</CODE> holding the longest sequence -common to both <VAR>array</VAR>s. -</P> -</DL> -<P> - -<A NAME="IDX1381"></A> -</P> -<DL> -<DT><U>Function:</U> <B>diff:edits</B> <I>array1 array2 =? p-lim</I> -<DD><P> - -<A NAME="IDX1382"></A> -<DT><U>Function:</U> <B>diff:edits</B> <I>array1 array2 =?</I> -<DD><VAR>array1</VAR> and <VAR>array2</VAR> are one-dimensional arrays. The procedure <VAR>=?</VAR> is used -to compare sequence tokens for equality. -</P> -<P> - -The non-negative integer <VAR>p-lim</VAR>, if provided, is maximum number of -deletions of the shorter sequence to allow. <CODE>diff:edits</CODE> will return <CODE>#f</CODE> -if more deletions would be necessary. -</P> -<P> - -<CODE>diff:edits</CODE> returns a vector of length <CODE>(diff:edit-length <VAR>array1</VAR> <VAR>array2</VAR>)</CODE> composed -of a shortest sequence of edits transformaing <VAR>array1</VAR> to <VAR>array2</VAR>. -</P> -<P> - -Each edit is an integer: -</P> -<DL COMPACT> -<DT><VAR>k</VAR> > 0 -<DD>Inserts <CODE>(array-ref <VAR>array1</VAR> (+ -1 <VAR>j</VAR>))</CODE> into the sequence. -<DT><VAR>k</VAR> < 0 -<DD>Deletes <CODE>(array-ref <VAR>array2</VAR> (- -1 <VAR>k</VAR>))</CODE> from the sequence. -</DL> -</DL> -<P> - -<A NAME="IDX1383"></A> -</P> -<DL> -<DT><U>Function:</U> <B>diff:edit-length</B> <I>array1 array2 =? p-lim</I> -<DD><P> - -<A NAME="IDX1384"></A> -<DT><U>Function:</U> <B>diff:edit-length</B> <I>array1 array2 =?</I> -<DD><VAR>array1</VAR> and <VAR>array2</VAR> are one-dimensional arrays. The procedure <VAR>=?</VAR> is used -to compare sequence tokens for equality. -</P> -<P> - -The non-negative integer <VAR>p-lim</VAR>, if provided, is maximum number of -deletions of the shorter sequence to allow. <CODE>diff:edit-length</CODE> will return <CODE>#f</CODE> -if more deletions would be necessary. -</P> -<P> - -<CODE>diff:edit-length</CODE> returns the length of the shortest sequence of edits transformaing -<VAR>array1</VAR> to <VAR>array2</VAR>. -</P> -</DL> -<TABLE><tr><td> </td><td class=example><pre>(diff:longest-common-subsequence "fghiejcklm" "fgehijkpqrlm" eqv?) -=> "fghijklm" - -(diff:edit-length "fghiejcklm" "fgehijkpqrlm" eqv?) -=> 6 - -(diff:edits "fghiejcklm" "fgehijkpqrlm" eqv?) -=> #As32(3 -5 -7 8 9 10) - ; e c h p q r -</pre></td></tr></table><P> - -<A NAME="Procedures"></A> -<HR SIZE="6"> -<A NAME="SEC225"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC224"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC226"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.3 Procedures </H2> -<!--docid::SEC225::--> -<P> - -Anything that doesn't fall neatly into any of the other categories winds -up here. -</P> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC226">7.3.1 Type Coercion</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'coerce</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC227">7.3.2 String-Case</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'string-case</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC228">7.3.3 String Ports</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'string-port</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC229">7.3.4 Line I/O</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'line-i/o</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC230">7.3.5 Multi-Processing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'process</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC231">7.3.6 Metric Units</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Portable manifest types for numeric values.</TD></TR> -</TABLE> -<P> - -<A NAME="Type Coercion"></A> -<HR SIZE="6"> -<A NAME="SEC226"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC227"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.1 Type Coercion </H3> -<!--docid::SEC226::--> -<CODE>(require 'coerce)</CODE> -<A NAME="IDX1385"></A> -<P> - -<A NAME="IDX1386"></A> -</P> -<DL> -<DT><U>Function:</U> <B>type-of</B> <I>obj</I> -<DD><P> - -Returns a symbol name for the type of <VAR>obj</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1387"></A> -</P> -<DL> -<DT><U>Function:</U> <B>coerce</B> <I>obj result-type</I> -<DD><P> - -Converts and returns <VAR>obj</VAR> of type <CODE>char</CODE>, <CODE>number</CODE>, -<CODE>string</CODE>, <CODE>symbol</CODE>, <CODE>list</CODE>, or <CODE>vector</CODE> to -<VAR>result-type</VAR> (which must be one of these symbols). -</P> -</DL> -<P> - -<A NAME="String-Case"></A> -<HR SIZE="6"> -<A NAME="SEC227"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC226"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC228"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.2 String-Case </H3> -<!--docid::SEC227::--> -<P> - -<CODE>(require 'string-case)</CODE> -<A NAME="IDX1388"></A> -</P> -<P> - -<A NAME="IDX1389"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>string-upcase</B> <I>str</I> -<DD><A NAME="IDX1390"></A> -<DT><U>Procedure:</U> <B>string-downcase</B> <I>str</I> -<DD><A NAME="IDX1391"></A> -<DT><U>Procedure:</U> <B>string-capitalize</B> <I>str</I> -<DD>The obvious string conversion routines. These are non-destructive. -</DL> -<P> - -<A NAME="IDX1392"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string-upcase!</B> <I>str</I> -<DD><A NAME="IDX1393"></A> -<DT><U>Function:</U> <B>string-downcase!</B> <I>str</I> -<DD><A NAME="IDX1394"></A> -<DT><U>Function:</U> <B>string-capitalize!</B> <I>str</I> -<DD>The destructive versions of the functions above. -</DL> -<P> - -<A NAME="IDX1395"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string-ci->symbol</B> <I>str</I> -<DD>Converts string <VAR>str</VAR> to a symbol having the same case as if the -symbol had been <CODE>read</CODE>. -</DL> -<P> - -<A NAME="IDX1396"></A> -</P> -<DL> -<DT><U>Function:</U> <B>symbol-append</B> <I>obj1 <small>...</small></I> -<DD>Converts <VAR>obj1</VAR> <small>...</small> to strings, appends them, and converts to a -symbol which is returned. Strings and numbers are converted to read's -symbol case; the case of symbol characters is not changed. #f is -converted to the empty string (symbol). -</DL> -<P> - -<A NAME="IDX1397"></A> -</P> -<DL> -<DT><U>Function:</U> <B>StudlyCapsExpand</B> <I>str delimiter</I> -<DD><A NAME="IDX1398"></A> -<DT><U>Function:</U> <B>StudlyCapsExpand</B> <I>str</I> -<DD><VAR>delimiter</VAR> must be a string or character. If absent, -<VAR>delimiter</VAR> defaults to `<SAMP>-</SAMP>'. <CODE>StudlyCapsExpand</CODE> returns a -copy of <VAR>str</VAR> where <VAR>delimiter</VAR> is inserted between each -lower-case character immediately followed by an upper-case character; -and between two upper-case characters immediately followed by a -lower-case character. -<P> - -<TABLE><tr><td> </td><td class=example><pre>(StudlyCapsExpand "aX" " ") => "a X" -(StudlyCapsExpand "aX" "..") => "a..X" -(StudlyCapsExpand "AX") => "AX" -(StudlyCapsExpand "Ax") => "Ax" -(StudlyCapsExpand "AXLE") => "AXLE" -(StudlyCapsExpand "aAXACz") => "a-AXA-Cz" -(StudlyCapsExpand "AaXACz") => "Aa-XA-Cz" -(StudlyCapsExpand "AAaXACz") => "A-Aa-XA-Cz" -(StudlyCapsExpand "AAaXAC") => "A-Aa-XAC" -</pre></td></tr></table><P> - -</P> -</DL> -<P> - -<A NAME="String Ports"></A> -<HR SIZE="6"> -<A NAME="SEC228"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC227"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC229"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.3 String Ports </H3> -<!--docid::SEC228::--> -<P> - -<CODE>(require 'string-port)</CODE> -<A NAME="IDX1399"></A> -</P> -<P> - -<A NAME="IDX1400"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>call-with-output-string</B> <I>proc</I> -<DD><VAR>proc</VAR> must be a procedure of one argument. This procedure calls -<VAR>proc</VAR> with one argument: a (newly created) output port. When the -function returns, the string composed of the characters written into the -port is returned. -</DL> -<P> - -<A NAME="IDX1401"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>call-with-input-string</B> <I>string proc</I> -<DD><VAR>proc</VAR> must be a procedure of one argument. This procedure calls -<VAR>proc</VAR> with one argument: an (newly created) input port from which -<VAR>string</VAR>'s contents may be read. When <VAR>proc</VAR> returns, the port -is closed and the value yielded by the procedure <VAR>proc</VAR> is -returned. -</DL> -<P> - -<A NAME="Line I/O"></A> -<HR SIZE="6"> -<A NAME="SEC229"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC228"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC230"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.4 Line I/O </H3> -<!--docid::SEC229::--> -<P> - -<CODE>(require 'line-i/o)</CODE> -<A NAME="IDX1402"></A> -</P> -<P> - -<A NAME="IDX1403"></A> -</P> -<DL> -<DT><U>Function:</U> <B>read-line</B> -<DD><P> - -<A NAME="IDX1404"></A> -<DT><U>Function:</U> <B>read-line</B> <I>port</I> -<DD>Returns a string of the characters up to, but not including a -newline or end of file, updating <VAR>port</VAR> to point to the -character following the newline. If no characters are available, an -end of file object is returned. The <VAR>port</VAR> argument may be -omitted, in which case it defaults to the value returned by -<CODE>current-input-port</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1405"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>read-line!</B> <I>string</I> -<DD><P> - -<A NAME="IDX1406"></A> -<DT><U>Procedure:</U> <B>read-line!</B> <I>string port</I> -<DD>Fills <VAR>string</VAR> with characters up to, but not including a newline or end -of file, updating the <VAR>port</VAR> to point to the last character read -or following the newline if it was read. If no characters are -available, an end of file object is returned. If a newline or end -of file was found, the number of characters read is returned. -Otherwise, <CODE>#f</CODE> is returned. The <VAR>port</VAR> argument may be -omitted, in which case it defaults to the value returned by -<CODE>current-input-port</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1407"></A> -</P> -<DL> -<DT><U>Function:</U> <B>write-line</B> <I>string</I> -<DD><P> - -<A NAME="IDX1408"></A> -<DT><U>Function:</U> <B>write-line</B> <I>string port</I> -<DD>Writes <VAR>string</VAR> followed by a newline to the given <VAR>port</VAR> and returns -an unspecified value. The <VAR>Port</VAR> argument may be omitted, in -which case it defaults to the value returned by -<CODE>current-input-port</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX1409"></A> -</P> -<DL> -<DT><U>Function:</U> <B>system->line</B> <I>command tmp</I> -<DD><P> - -<A NAME="IDX1410"></A> -<DT><U>Function:</U> <B>system->line</B> <I>command</I> -<DD><VAR>command</VAR> must be a string. The string <VAR>tmp</VAR>, if supplied, is a path to use as -a temporary file. <CODE>system->line</CODE> calls <CODE>system</CODE> with <VAR>command</VAR> as argument, -redirecting stdout to file <VAR>tmp</VAR>. <CODE>system->line</CODE> returns a string containing the -first line of output from <VAR>tmp</VAR>. -</P> -</DL> -<P> - -<A NAME="Multi-Processing"></A> -<HR SIZE="6"> -<A NAME="SEC230"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC229"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC231"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.5 Multi-Processing </H3> -<!--docid::SEC230::--> -<P> - -<CODE>(require 'process)</CODE> -<A NAME="IDX1411"></A> -</P> -<P> - -This module implements asynchronous (non-polled) time-sliced -multi-processing in the SCM Scheme implementation using procedures -<CODE>alarm</CODE> and <CODE>alarm-interrupt</CODE>. -<A NAME="IDX1412"></A> -<A NAME="IDX1413"></A> -Until this is ported to another implementation, consider it an example -of writing schedulers in Scheme. -</P> -<P> - -<A NAME="IDX1414"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>add-process!</B> <I>proc</I> -<DD>Adds proc, which must be a procedure (or continuation) capable of -accepting accepting one argument, to the <CODE>process:queue</CODE>. The -value returned is unspecified. The argument to <VAR>proc</VAR> should be -ignored. If <VAR>proc</VAR> returns, the process is killed. -</DL> -<P> - -<A NAME="IDX1415"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>process:schedule!</B> -<DD>Saves the current process on <CODE>process:queue</CODE> and runs the next -process from <CODE>process:queue</CODE>. The value returned is -unspecified. -</DL> -<P> - -<A NAME="IDX1416"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>kill-process!</B> -<DD>Kills the current process and runs the next process from -<CODE>process:queue</CODE>. If there are no more processes on -<CODE>process:queue</CODE>, <CODE>(slib:exit)</CODE> is called (see section <A HREF="slib_2.html#SEC17">2.4 System</A>). -</DL> -<P> - -<A NAME="Metric Units"></A> -<HR SIZE="6"> -<A NAME="SEC231"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC230"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC232"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.3.6 Metric Units </H3> -<!--docid::SEC231::--> -<P> - -<CODE>(require 'metric-units)</CODE> -<A NAME="IDX1417"></A> -</P> -<P> - -<A HREF="http://swissnet.ai.mit.edu/~jaffer/MIXF.html">http://swissnet.ai.mit.edu/~jaffer/MIXF.html</A> -</P> -<P> - -<EM>Metric Interchange Format</EM> is a character string encoding for -numerical values and units which: -</P> -<P> - -<UL> -<LI> -is unambiguous in all locales; -<P> - -</P> -<LI> -uses only [TOG] "Portable Character Set" characters matching "Basic -Latin" characters in Plane 0 of the Universal Character Set [UCS]; -<P> - -</P> -<LI> -is transparent to [UTF-7] and [UTF-8] UCS transformation formats; -<P> - -</P> -<LI> -is human readable and writable; -<P> - -</P> -<LI> -is machine readable and writable; -<P> - -</P> -<LI> -incorporates SI prefixes and units; -<P> - -</P> -<LI> -incorporates [ISO 6093] numbers; and -<P> - -</P> -<LI> -incorporates [IEC 60027-2] binary prefixes. -</UL> -<P> - -In the expression for the value of a quantity, the unit symbol is placed -after the numerical value. A dot (PERIOD, `<SAMP>.</SAMP>') is placed between -the numerical value and the unit symbol. -</P> -<P> - -Within a compound unit, each of the base and derived symbols can -optionally have an attached SI prefix. -</P> -<P> - -Unit symbols formed from other unit symbols by multiplication are -indicated by means of a dot (PERIOD, `<SAMP>.</SAMP>') placed between them. -</P> -<P> - -Unit symbols formed from other unit symbols by division are indicated by -means of a SOLIDUS (`<SAMP>/</SAMP>') or negative exponents. The SOLIDUS must -not be repeated in the same compound unit unless contained within a -parenthesized subexpression. -</P> -<P> - -The grouping formed by a prefix symbol attached to a unit symbol -constitutes a new inseparable symbol (forming a multiple or submultiple -of the unit concerned) which can be raised to a positive or negative -power and which can be combined with other unit symbols to form compound -unit symbols. -</P> -<P> - -The grouping formed by surrounding compound unit symbols with -parentheses (`<SAMP>(</SAMP>' and `<SAMP>)</SAMP>') constitutes a new inseparable symbol -which can be raised to a positive or negative power and which can be -combined with other unit symbols to form compound unit symbols. -</P> -<P> - -Compound prefix symbols, that is, prefix symbols formed by the -juxtaposition of two or more prefix symbols, are not permitted. -</P> -<P> - -Prefix symbols are not used with the time-related unit symbols min -(minute), h (hour), d (day). No prefix symbol may be used with dB -(decibel). Only submultiple prefix symbols may be used with the unit -symbols L (liter), Np (neper), o (degree), oC (degree Celsius), rad -(radian), and sr (steradian). Submultiple prefix symbols may not be -used with the unit symbols t (metric ton), r (revolution), or Bd (baud). -</P> -<P> - -A unit exponent follows the unit, separated by a CIRCUMFLEX (`<SAMP>^</SAMP>'). -Exponents may be positive or negative. Fractional exponents must be -parenthesized. -</P> -<P> - -<HR SIZE="6"> -<A NAME="SEC232"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC231"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC233"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.3.6.1 SI Prefixes </H4> -<!--docid::SEC232::--> -<TABLE><tr><td> </td><td class=example><pre> Factor Name Symbol | Factor Name Symbol - ====== ==== ====== | ====== ==== ====== - 1e24 yotta Y | 1e-1 deci d - 1e21 zetta Z | 1e-2 centi c - 1e18 exa E | 1e-3 milli m - 1e15 peta P | 1e-6 micro u - 1e12 tera T | 1e-9 nano n - 1e9 giga G | 1e-12 pico p - 1e6 mega M | 1e-15 femto f - 1e3 kilo k | 1e-18 atto a - 1e2 hecto h | 1e-21 zepto z - 1e1 deka da | 1e-24 yocto y -</pre></td></tr></table><P> - -<HR SIZE="6"> -<A NAME="SEC233"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC232"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC234"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.3.6.2 Binary Prefixes </H4> -<!--docid::SEC233::--> -<P> - -These binary prefixes are valid only with the units B (byte) and bit. -However, decimal prefixes can also be used with bit; and decimal -multiple (not submultiple) prefixes can also be used with B (byte). -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre> Factor (power-of-2) Name Symbol - ====== ============ ==== ====== - 1.152921504606846976e18 (2^60) exbi Ei - 1.125899906842624e15 (2^50) pebi Pi - 1.099511627776e12 (2^40) tebi Ti - 1.073741824e9 (2^30) gibi Gi - 1.048576e6 (2^20) mebi Mi - 1.024e3 (2^10) kibi Ki -</pre></td></tr></table><P> - -<HR SIZE="6"> -<A NAME="SEC234"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC233"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC225"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.3.6.3 Unit Symbols </H4> -<!--docid::SEC234::--> -<P> - -<TABLE><tr><td> </td><td class=example><pre> Type of Quantity Name Symbol Equivalent - ================ ==== ====== ========== -time second s -time minute min = 60.s -time hour h = 60.min -time day d = 24.h -frequency hertz Hz s^-1 -signaling rate baud Bd s^-1 -length meter m -volume liter L dm^3 -plane angle radian rad -solid angle steradian sr rad^2 -plane angle revolution * r = 6.283185307179586.rad -plane angle degree * o = 2.777777777777778e-3.r -information capacity bit bit -information capacity byte, octet B = 8.bit -mass gram g -mass ton t Mg -mass unified atomic mass unit u = 1.66053873e-27.kg -amount of substance mole mol -catalytic activity katal kat mol/s -thermodynamic temperature kelvin K -centigrade temperature degree Celsius oC -luminous intensity candela cd -luminous flux lumen lm cd.sr -illuminance lux lx lm/m^2 -force newton N m.kg.s^-2 -pressure, stress pascal Pa N/m^2 -energy, work, heat joule J N.m -energy electronvolt eV = 1.602176462e-19.J -power, radiant flux watt W J/s -logarithm of power ratio neper Np -logarithm of power ratio decibel * dB = 0.1151293.Np -electric current ampere A -electric charge coulomb C s.A -electric potential, EMF volt V W/A -capacitance farad F C/V -electric resistance ohm Ohm V/A -electric conductance siemens S A/V -magnetic flux weber Wb V.s -magnetic flux density tesla T Wb/m^2 -inductance henry H Wb/A -radionuclide activity becquerel Bq s^-1 -absorbed dose energy gray Gy m^2.s^-2 -dose equivalent sievert Sv m^2.s^-2 -</pre></td></tr></table><P> - -* The formulas are: -</P> -<P> - -<UL> -<LI> -r/rad = 8 * atan(1) -<LI> -o/r = 1 / 360 -<LI> -db/Np = ln(10) / 20 -</UL> -<P> - -<A NAME="IDX1418"></A> -</P> -<DL> -<DT><U>Function:</U> <B>si:conversion-factor</B> <I>to-unit from-unit</I> -<DD>If the strings <VAR>from-unit</VAR> and <VAR>to-unit</VAR> express valid unit -expressions for quantities of the same unit-dimensions, then the value -returned by <CODE>si:conversion-factor</CODE> will be such that multiplying a -numerical value expressed in <VAR>from-unit</VAR>s by the returned conversion -factor yields the numerical value expressed in <VAR>to-unit</VAR>s. -<P> - -Otherwise, <CODE>si:conversion-factor</CODE> returns: -</P> -<P> - -</P> -<DL COMPACT> -<DT>-3 -<DD>if neither <VAR>from-unit</VAR> nor <VAR>to-unit</VAR> is a syntactically valid -unit. -<DT>-2 -<DD>if <VAR>from-unit</VAR> is not a syntactically valid unit. -<DT>-1 -<DD>if <VAR>to-unit</VAR> is not a syntactically valid unit. -<DT>0 -<DD>if linear conversion (by a factor) is not possible. -</DL> -<P> - -</P> -</DL> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(si:conversion-factor "km/s" "m/s" ) => 0.001 -(si:conversion-factor "N" "m/s" ) => 0 -(si:conversion-factor "moC" "oC" ) => 1000 -(si:conversion-factor "mK" "oC" ) => 0 -(si:conversion-factor "rad" "o" ) => 0.0174533 -(si:conversion-factor "K" "o" ) => 0 -(si:conversion-factor "K" "K" ) => 1 -(si:conversion-factor "oK" "oK" ) => -3 -(si:conversion-factor "" "s/s" ) => 1 -(si:conversion-factor "km/h" "mph" ) => -2 -</pre></td></tr></table><P> - -<A NAME="Standards Support"></A> -<HR SIZE="6"> -<A NAME="SEC235"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC234"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC236"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.4 Standards Support </H2> -<!--docid::SEC235::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC236">7.4.1 RnRS</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Revised Reports on Scheme</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC237">7.4.2 With-File</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'with-file</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC238">7.4.3 Transcripts</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'transcript</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC239">7.4.4 Rev2 Procedures</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'rev2-procedures</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC240">7.4.5 Rev4 Optional Procedures</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'rev4-optional-procedures</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC241">7.4.6 Multi-argument / and -</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'multiarg/and-</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC242">7.4.7 Multi-argument Apply</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'multiarg-apply</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC243">7.4.8 Rationalize</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'rationalize</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC244">7.4.9 Promises</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'delay</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC245">7.4.10 Dynamic-Wind</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'dynamic-wind</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC246">7.4.11 Eval</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'eval</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC247">7.4.12 Values</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'values</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC248">7.4.13 SRFI</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'http://srfi.schemers.org/srfi-0/srfi-0.html</TD></TR> -</TABLE> -<P> - -<A NAME="RnRS"></A> -<HR SIZE="6"> -<A NAME="SEC236"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC237"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.1 RnRS </H3> -<!--docid::SEC236::--> -<P> - -The <CODE>r2rs</CODE>, <CODE>r3rs</CODE>, <CODE>r4rs</CODE>, and <CODE>r5rs</CODE> features -attempt to provide procedures and macros to bring a Scheme -implementation to the desired version of Scheme. -</P> -<P> - -<A NAME="IDX1419"></A> -</P> -<DL> -<DT><U>Feature:</U> <B>r2rs</B> -<DD><A NAME="IDX1420"></A> -Requires features implementing procedures and optional procedures -specified by <CITE>Revised^2 Report on the Algorithmic Language Scheme</CITE>; -namely <CODE>rev3-procedures</CODE> and <CODE>rev2-procedures</CODE>. -</DL> -<P> - -<A NAME="IDX1421"></A> -</P> -<DL> -<DT><U>Feature:</U> <B>r3rs</B> -<DD><A NAME="IDX1422"></A> -Requires features implementing procedures and optional procedures -specified by <CITE>Revised^3 Report on the Algorithmic Language Scheme</CITE>; -namely <CODE>rev3-procedures</CODE>. -<P> - -<EM>Note:</EM> SLIB already mandates the <CODE>r3rs</CODE> procedures which can -be portably implemented in <CODE>r4rs</CODE> implementations. -</P> -</DL> -<P> - -<A NAME="IDX1423"></A> -</P> -<DL> -<DT><U>Feature:</U> <B>r4rs</B> -<DD><A NAME="IDX1424"></A> -Requires features implementing procedures and optional procedures -specified by <CITE>Revised^4 Report on the Algorithmic Language Scheme</CITE>; -namely <CODE>rev4-optional-procedures</CODE>. -</DL> -<P> - -<A NAME="IDX1425"></A> -</P> -<DL> -<DT><U>Feature:</U> <B>r5rs</B> -<DD><A NAME="IDX1426"></A> -Requires features implementing procedures and optional procedures -specified by <CITE>Revised^5 Report on the Algorithmic Language Scheme</CITE>; -namely <CODE>values</CODE>, <CODE>macro</CODE>, and <CODE>eval</CODE>. -</DL> -<P> - -<A NAME="With-File"></A> -<HR SIZE="6"> -<A NAME="SEC237"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC236"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC238"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.2 With-File </H3> -<!--docid::SEC237::--> -<P> - -<CODE>(require 'with-file)</CODE> -<A NAME="IDX1427"></A> -</P> -<P> - -<A NAME="IDX1428"></A> -</P> -<DL> -<DT><U>Function:</U> <B>with-input-from-file</B> <I>file thunk</I> -<DD><A NAME="IDX1429"></A> -<DT><U>Function:</U> <B>with-output-to-file</B> <I>file thunk</I> -<DD>Description found in R4RS. -</DL> -<P> - -<A NAME="Transcripts"></A> -<HR SIZE="6"> -<A NAME="SEC238"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC237"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC239"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.3 Transcripts </H3> -<!--docid::SEC238::--> -<P> - -<CODE>(require 'transcript)</CODE> -<A NAME="IDX1430"></A> -</P> -<P> - -<A NAME="IDX1431"></A> -</P> -<DL> -<DT><U>Function:</U> <B>transcript-on</B> <I>filename</I> -<DD><A NAME="IDX1432"></A> -<DT><U>Function:</U> <B>transcript-off</B> <I>filename</I> -<DD>Redefines <CODE>read-char</CODE>, <CODE>read</CODE>, <CODE>write-char</CODE>, -<CODE>write</CODE>, <CODE>display</CODE>, and <CODE>newline</CODE>. -</DL> -<P> - -<A NAME="Rev2 Procedures"></A> -<HR SIZE="6"> -<A NAME="SEC239"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC238"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC240"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.4 Rev2 Procedures </H3> -<!--docid::SEC239::--> -<P> - -<CODE>(require 'rev2-procedures)</CODE> -<A NAME="IDX1433"></A> -</P> -<P> - -The procedures below were specified in the <CITE>Revised^2 Report on -Scheme</CITE>. <STRONG>N.B.</STRONG>: The symbols <CODE>1+</CODE> and <CODE>-1+</CODE> are not -<CITE>R4RS</CITE> syntax. Scheme->C, for instance, chokes on this -module. -</P> -<P> - -<A NAME="IDX1434"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>substring-move-left!</B> <I>string1 start1 end1 string2 start2</I> -<DD><A NAME="IDX1435"></A> -<DT><U>Procedure:</U> <B>substring-move-right!</B> <I>string1 start1 end1 string2 start2</I> -<DD><VAR>string1</VAR> and <VAR>string2</VAR> must be a strings, and <VAR>start1</VAR>, -<VAR>start2</VAR> and <VAR>end1</VAR> must be exact integers satisfying -<P> - -<TABLE><tr><td> </td><td class=display><pre style="font-family: serif">0 <= <VAR>start1</VAR> <= <VAR>end1</VAR> <= (string-length <VAR>string1</VAR>) -0 <= <VAR>start2</VAR> <= <VAR>end1</VAR> - <VAR>start1</VAR> + <VAR>start2</VAR> <= (string-length <VAR>string2</VAR>) -</pre></td></tr></table><P> - -<CODE>substring-move-left!</CODE> and <CODE>substring-move-right!</CODE> store -characters of <VAR>string1</VAR> beginning with index <VAR>start1</VAR> -(inclusive) and ending with index <VAR>end1</VAR> (exclusive) into -<VAR>string2</VAR> beginning with index <VAR>start2</VAR> (inclusive). -</P> -<P> - -<CODE>substring-move-left!</CODE> stores characters in time order of -increasing indices. <CODE>substring-move-right!</CODE> stores characters in -time order of increasing indeces. -</P> -</DL> -<P> - -<A NAME="IDX1436"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>substring-fill!</B> <I>string start end char</I> -<DD>Fills the elements <VAR>start</VAR>--<VAR>end</VAR> of <VAR>string</VAR> with the -character <VAR>char</VAR>. -</DL> -<P> - -<A NAME="IDX1437"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string-null?</B> <I>str</I> -<DD>== <CODE>(= 0 (string-length <VAR>str</VAR>))</CODE> -</DL> -<P> - -<A NAME="IDX1438"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>append!</B> <I>pair1 <small>...</small></I> -<DD>Destructively appends its arguments. Equivalent to <CODE>nconc</CODE>. -</DL> -<P> - -<A NAME="IDX1439"></A> -</P> -<DL> -<DT><U>Function:</U> <B>1+</B> <I>n</I> -<DD>Adds 1 to <VAR>n</VAR>. -</DL> -<P> - -<A NAME="IDX1440"></A> -</P> -<DL> -<DT><U>Function:</U> <B>-1+</B> <I>n</I> -<DD>Subtracts 1 from <VAR>n</VAR>. -</DL> -<P> - -<A NAME="IDX1441"></A> -</P> -<DL> -<DT><U>Function:</U> <B><?</B> -<DD><A NAME="IDX1442"></A> -<DT><U>Function:</U> <B><=?</B> -<DD><A NAME="IDX1443"></A> -<DT><U>Function:</U> <B>=?</B> -<DD><A NAME="IDX1444"></A> -<DT><U>Function:</U> <B>>?</B> -<DD><A NAME="IDX1445"></A> -<DT><U>Function:</U> <B>>=?</B> -<DD>These are equivalent to the procedures of the same name but without the -trailing `<SAMP>?</SAMP>'. -</DL> -<P> - -<A NAME="Rev4 Optional Procedures"></A> -<HR SIZE="6"> -<A NAME="SEC240"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC239"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC241"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.5 Rev4 Optional Procedures </H3> -<!--docid::SEC240::--> -<P> - -<CODE>(require 'rev4-optional-procedures)</CODE> -<A NAME="IDX1446"></A> -</P> -<P> - -For the specification of these optional procedures, -See section `Standard procedures' in <CITE>Revised(4) Scheme</CITE>. -</P> -<P> - -<A NAME="IDX1447"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list-tail</B> <I>l p</I> -<DD></DL> -<P> - -<A NAME="IDX1448"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string->list</B> <I>s</I> -<DD></DL> -<P> - -<A NAME="IDX1449"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list->string</B> <I>l</I> -<DD></DL> -<P> - -<A NAME="IDX1450"></A> -</P> -<DL> -<DT><U>Function:</U> <B>string-copy</B> -<DD></DL> -<P> - -<A NAME="IDX1451"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>string-fill!</B> <I>s obj</I> -<DD></DL> -<P> - -<A NAME="IDX1452"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list->vector</B> <I>l</I> -<DD></DL> -<P> - -<A NAME="IDX1453"></A> -</P> -<DL> -<DT><U>Function:</U> <B>vector->list</B> <I>s</I> -<DD></DL> -<P> - -<A NAME="IDX1454"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>vector-fill!</B> <I>s obj</I> -<DD></DL> -<P> - -<A NAME="Multi-argument / and -"></A> -<HR SIZE="6"> -<A NAME="SEC241"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC240"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC242"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.6 Multi-argument / and - </H3> -<!--docid::SEC241::--> -<P> - -<CODE>(require 'multiarg/and-)</CODE> -<A NAME="IDX1455"></A> -</P> -<P> - -For the specification of these optional forms, See section `Numerical operations' in <CITE>Revised(4) Scheme</CITE>. -</P> -<P> - -<A NAME="IDX1456"></A> -</P> -<DL> -<DT><U>Function:</U> <B>/</B> <I>dividend divisor1 <small>...</small></I> -<DD></DL> -<P> - -<A NAME="IDX1457"></A> -</P> -<DL> -<DT><U>Function:</U> <B>-</B> <I>minuend subtrahend1 <small>...</small></I> -<DD></DL> -<P> - -<A NAME="Multi-argument Apply"></A> -<HR SIZE="6"> -<A NAME="SEC242"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC241"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC243"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.7 Multi-argument Apply </H3> -<!--docid::SEC242::--> -<P> - -<CODE>(require 'multiarg-apply)</CODE> -<A NAME="IDX1458"></A> -</P> -<P> - -For the specification of this optional form, -See section `Control features' in <CITE>Revised(4) Scheme</CITE>. -</P> -<P> - -<A NAME="IDX1459"></A> -</P> -<DL> -<DT><U>Function:</U> <B>apply</B> <I>proc arg1 <small>...</small></I> -<DD></DL> -<P> - -<A NAME="Rationalize"></A> -<HR SIZE="6"> -<A NAME="SEC243"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC242"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC244"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.8 Rationalize </H3> -<!--docid::SEC243::--> -<P> - -<CODE>(require 'rationalize)</CODE> -<A NAME="IDX1460"></A> -</P> -<P> - -<A NAME="IDX1461"></A> -</P> -<DL> -<DT><U>Function:</U> <B>rationalize</B> <I>x e</I> -<DD><P> - -Computes the correct result for exact arguments (provided the -implementation supports exact rational numbers of unlimited precision); -and produces a reasonable answer for inexact arguments when inexact -arithmetic is implemented using floating-point. -</P> -<P> - -</P> -</DL> -<CODE>Rationalize</CODE> has limited use in implementations lacking exact -(non-integer) rational numbers. The following procedures return a list -of the numerator and denominator. -<P> - -<A NAME="IDX1462"></A> -</P> -<DL> -<DT><U>Function:</U> <B>find-ratio</B> <I>x e</I> -<DD><P> - -<CODE>find-ratio</CODE> returns the list of the <EM>simplest</EM> -numerator and denominator whose quotient differs from <VAR>x</VAR> by no more -than <VAR>e</VAR>. -</P> -<P> - -<TABLE><tr><td> </td><td class=display><pre style="font-family: serif"><TT>(find-ratio 3/97 .0001) => (3 97) -(find-ratio 3/97 .001) => (1 32) -</TT> -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1463"></A> -</P> -<DL> -<DT><U>Function:</U> <B>find-ratio-between</B> <I>x y</I> -<DD><P> - -<CODE>find-ratio-between</CODE> returns the list of the <EM>simplest</EM> -numerator and denominator between <VAR>x</VAR> and <VAR>y</VAR>. -</P> -<P> - -<TABLE><tr><td> </td><td class=display><pre style="font-family: serif"><TT>(find-ratio-between 2/7 3/5) => (1 2) -(find-ratio-between -3/5 -2/7) => (-1 2) -</TT> -</pre></td></tr></table></DL> -<P> - -<A NAME="Promises"></A> -<HR SIZE="6"> -<A NAME="SEC244"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC243"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC245"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.9 Promises </H3> -<!--docid::SEC244::--> -<P> - -<CODE>(require 'promise)</CODE> -<A NAME="IDX1464"></A> -</P> -<P> - -<A NAME="IDX1465"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-promise</B> <I>proc</I> -<DD></DL> -<P> - -<A NAME="IDX1466"></A> -</P> -<DL> -<DT><U>Function:</U> <B>force</B> <I>promise</I> -<DD></DL> -<P> - -<CODE>(require 'delay)</CODE> provides <CODE>force</CODE> and <CODE>delay</CODE>: -</P> -<P> - -<A NAME="IDX1467"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>delay</B> <I>obj</I> -<DD>Change occurrences of <CODE>(delay <VAR>expression</VAR>)</CODE> to -<P> - -<TABLE><tr><td> </td><td class=example><pre>(make-promise (lambda () <VAR>expression</VAR>)) -</pre></td></tr></table><P> - -</P> -</DL> -<P> - -(see section `Control features' in <CITE>Revised(4) Scheme</CITE>). -</P> -<P> - -<A NAME="Dynamic-Wind"></A> -<HR SIZE="6"> -<A NAME="SEC245"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC244"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC246"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.10 Dynamic-Wind </H3> -<!--docid::SEC245::--> -<P> - -<CODE>(require 'dynamic-wind)</CODE> -<A NAME="IDX1468"></A> -</P> -<P> - -This facility is a generalization of Common LISP <CODE>unwind-protect</CODE>, -designed to take into account the fact that continuations produced by -<CODE>call-with-current-continuation</CODE> may be reentered. -</P> -<P> - -<A NAME="IDX1469"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>dynamic-wind</B> <I>thunk1 thunk2 thunk3</I> -<DD>The arguments <VAR>thunk1</VAR>, <VAR>thunk2</VAR>, and <VAR>thunk3</VAR> must all be -procedures of no arguments (thunks). -<P> - -<CODE>dynamic-wind</CODE> calls <VAR>thunk1</VAR>, <VAR>thunk2</VAR>, and then -<VAR>thunk3</VAR>. The value returned by <VAR>thunk2</VAR> is returned as the -result of <CODE>dynamic-wind</CODE>. <VAR>thunk3</VAR> is also called just before -control leaves the dynamic context of <VAR>thunk2</VAR> by calling a -continuation created outside that context. Furthermore, <VAR>thunk1</VAR> is -called before reentering the dynamic context of <VAR>thunk2</VAR> by calling -a continuation created inside that context. (Control is inside the -context of <VAR>thunk2</VAR> if <VAR>thunk2</VAR> is on the current return stack). -</P> -<P> - -<STRONG>Warning:</STRONG> There is no provision for dealing with errors or -interrupts. If an error or interrupt occurs while using -<CODE>dynamic-wind</CODE>, the dynamic environment will be that in effect at -the time of the error or interrupt. -</P> -</DL> -<P> - -<A NAME="Eval"></A> -<HR SIZE="6"> -<A NAME="SEC246"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC245"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC247"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.11 Eval </H3> -<!--docid::SEC246::--> -<P> - -<CODE>(require 'eval)</CODE> -<A NAME="IDX1470"></A> -</P> -<P> - -<A NAME="IDX1471"></A> -</P> -<DL> -<DT><U>Function:</U> <B>eval</B> <I>expression environment-specifier</I> -<DD><P> - -Evaluates <VAR>expression</VAR> in the specified environment and returns its -value. <VAR>Expression</VAR> must be a valid Scheme expression represented -as data, and <VAR>environment-specifier</VAR> must be a value returned by one -of the three procedures described below. Implementations may extend -<CODE>eval</CODE> to allow non-expression programs (definitions) as the first -argument and to allow other values as environments, with the restriction -that <CODE>eval</CODE> is not allowed to create new bindings in the -environments associated with <CODE>null-environment</CODE> or -<CODE>scheme-report-environment</CODE>. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(eval '(* 7 3) (scheme-report-environment 5)) - => 21 - -(let ((f (eval '(lambda (f x) (f x x)) - (null-environment)))) - (f + 10)) - => 20 -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1472"></A> -</P> -<DL> -<DT><U>Function:</U> <B>scheme-report-environment</B> <I>version</I> -<DD><A NAME="IDX1473"></A> -<DT><U>Function:</U> <B>null-environment</B> <I>version</I> -<DD><A NAME="IDX1474"></A> -<DT><U>Function:</U> <B>null-environment</B> -<DD><P> - -<VAR>Version</VAR> must be an exact non-negative integer <VAR>n</VAR> -corresponding to a version of one of the Revised^<VAR>n</VAR> Reports on -Scheme. <CODE>Scheme-report-environment</CODE> returns a specifier for an -environment that contains the set of bindings specified in the -corresponding report that the implementation supports. -<CODE>Null-environment</CODE> returns a specifier for an environment that -contains only the (syntactic) bindings for all the syntactic keywords -defined in the given version of the report. -</P> -<P> - -Not all versions may be available in all implementations at all times. -However, an implementation that conforms to version <VAR>n</VAR> of the -Revised^<VAR>n</VAR> Reports on Scheme must accept version <VAR>n</VAR>. An error -is signalled if the specified version is not available. -</P> -<P> - -The effect of assigning (through the use of <CODE>eval</CODE>) a variable -bound in a <CODE>scheme-report-environment</CODE> (for example <CODE>car</CODE>) is -unspecified. Thus the environments specified by -<CODE>scheme-report-environment</CODE> may be immutable. -</P> -<P> - -</P> -</DL> -<P> - -<A NAME="IDX1475"></A> -</P> -<DL> -<DT><U>Function:</U> <B>interaction-environment</B> -<DD><P> - -This optional procedure returns a specifier for the environment that -contains implementation-defined bindings, typically a superset of those -listed in the report. The intent is that this procedure will return the -environment in which the implementation would evaluate expressions -dynamically typed by the user. -</P> -</DL> -<P> - -Here are some more <CODE>eval</CODE> examples: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(require 'eval) -=> #<unspecified> -(define car 'volvo) -=> #<unspecified> -car -=> volvo -(eval 'car (interaction-environment)) -=> volvo -(eval 'car (scheme-report-environment 5)) -=> #<primitive-procedure car> -(eval '(eval 'car (interaction-environment)) - (scheme-report-environment 5)) -=> volvo -(eval '(eval '(set! car 'buick) (interaction-environment)) - (scheme-report-environment 5)) -=> #<unspecified> -car -=> buick -(eval 'car (scheme-report-environment 5)) -=> #<primitive-procedure car> -(eval '(eval 'car (interaction-environment)) - (scheme-report-environment 5)) -=> buick -</pre></td></tr></table><P> - -<A NAME="Values"></A> -<HR SIZE="6"> -<A NAME="SEC247"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC246"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.12 Values </H3> -<!--docid::SEC247::--> -<P> - -<CODE>(require 'values)</CODE> -<A NAME="IDX1476"></A> -</P> -<P> - -<A NAME="IDX1477"></A> -</P> -<DL> -<DT><U>Function:</U> <B>values</B> <I>obj <small>...</small></I> -<DD><CODE>values</CODE> takes any number of arguments, and passes (returns) them -to its continuation. -</DL> -<P> - -<A NAME="IDX1478"></A> -</P> -<DL> -<DT><U>Function:</U> <B>call-with-values</B> <I>thunk proc</I> -<DD><VAR>thunk</VAR> must be a procedure of no arguments, and <VAR>proc</VAR> must be -a procedure. <CODE>call-with-values</CODE> calls <VAR>thunk</VAR> with a -continuation that, when passed some values, calls <VAR>proc</VAR> with those -values as arguments. -<P> - -Except for continuations created by the <CODE>call-with-values</CODE> -procedure, all continuations take exactly one value, as now; the effect -of passing no value or more than one value to continuations that were -not created by the <CODE>call-with-values</CODE> procedure is -unspecified. -</P> -</DL> -<P> - -<A NAME="SRFI"></A> -<HR SIZE="6"> -<A NAME="SEC248"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC247"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC249"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC235"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.4.13 SRFI </H3> -<!--docid::SEC248::--> -<P> - -<CODE>(require 'srfi)</CODE> -<A NAME="IDX1479"></A> -</P> -<P> - -Implements <EM>Scheme Request For Implementation</EM> (SRFI) as -<A NAME="IDX1480"></A> -described at <A HREF="http://srfi.schemers.org/">http://srfi.schemers.org/</A> -</P> -<P> - -The Copyright terms of each SRFI states: -<BLOCKQUOTE> -"However, this document itself may not be modified in any way, ..." -</BLOCKQUOTE> -<P> - -Therefore, the specification of SRFI constructs must not be -quoted without including the complete SRFI document containing -discussion and a sample implementation program. -</P> -<P> - -<A NAME="IDX1481"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>cond-expand</B> <I><clause1> <clause2> <small>...</small></I> -<DD><P> - -<EM>Syntax:</EM> -Each <clause> should be of the form -</P> -<P> - -<TABLE><tr><td> </td><td class=display><pre style="font-family: serif"><TT>(<feature> <expression1> <small>...</small>)</TT> -</pre></td></tr></table><P> - -where <feature> is a boolean expression composed of symbols and -`and', `or', and `not' of boolean expressions. The last <clause> -may be an "else clause," which has the form -</P> -<P> - -<TABLE><tr><td> </td><td class=display><pre style="font-family: serif"><TT>(else <expression1> <expression2> <small>...</small>).</TT> -</pre></td></tr></table><P> - -The first clause whose feature expression is satisfied is expanded. -If no feature expression is satisfied and there is no else clause, an -error is signaled. -</P> -<P> - -SLIB <CODE>cond-expand</CODE> is an extension of SRFI-0, -<A HREF="http://srfi.schemers.org/srfi-0/srfi-0.html">http://srfi.schemers.org/srfi-0/srfi-0.html</A>. -</P> -</DL> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC249">7.4.13.1 SRFI-1</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">list-processing</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC260">7.4.13.2 SRFI-2</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">guarded LET* special form</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC261">7.4.13.3 SRFI-8</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Binding to multiple values</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC262">7.4.13.4 SRFI-9</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Defining Record Types</TD></TR> -</TABLE> -<P> - -<A NAME="SRFI-1"></A> -<HR SIZE="6"> -<A NAME="SEC249"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC260"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.4.13.1 SRFI-1 </H4> -<!--docid::SEC249::--> -<P> - -<CODE>(require 'srfi-1)</CODE> -<A NAME="IDX1482"></A> -</P> -<P> - -Implements the <EM>SRFI-1</EM> <EM>list-processing library</EM> as described -<A NAME="IDX1483"></A> -<A NAME="IDX1484"></A> -at <A HREF="http://srfi.schemers.org/srfi-1/srfi-1.html">http://srfi.schemers.org/srfi-1/srfi-1.html</A> -</P> -<P> - -<A NAME="SEC250"></A> -<H3> Constructors </H3> -<!--docid::SEC250::--> -<P> - -<A NAME="IDX1485"></A> -</P> -<DL> -<DT><U>Function:</U> <B>xcons</B> <I>d a</I> -<DD><CODE>(define (xcons d a) (cons a d))</CODE>. -</DL> -<P> - -<A NAME="IDX1486"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list-tabulate</B> <I>len proc</I> -<DD>Returns a list of length <VAR>len</VAR>. Element <VAR>i</VAR> is <CODE>(<VAR>proc</VAR> -<VAR>i</VAR>)</CODE> for 0 <= <VAR>i</VAR> < <VAR>len</VAR>. -</DL> -<P> - -<A NAME="IDX1487"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cons*</B> <I>obj1 obj2</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1488"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list-copy</B> <I>flist</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1489"></A> -</P> -<DL> -<DT><U>Function:</U> <B>iota</B> <I>count start step</I> -<DD><P> - -<A NAME="IDX1490"></A> -<DT><U>Function:</U> <B>iota</B> <I>count start</I> -<DD></P> -<P> - -<A NAME="IDX1491"></A> -<DT><U>Function:</U> <B>iota</B> <I>count</I> -<DD>Returns a list of <VAR>count</VAR> numbers: (<VAR>start</VAR>, <VAR>start</VAR>+<VAR>step</VAR>, <small>...</small>, <VAR>start</VAR>+(<VAR>count</VAR>-1)*<VAR>step</VAR>). -</P> -</DL> -<P> - -<A NAME="IDX1492"></A> -</P> -<DL> -<DT><U>Function:</U> <B>circular-list</B> <I>obj1 obj2 <small>...</small></I> -<DD><P> - -Returns a circular list of <VAR>obj1</VAR>, <VAR>obj2</VAR>, <small>...</small>. -</P> -</DL> -<A NAME="SEC251"></A> -<H3> Predicates </H3> -<!--docid::SEC251::--> -<P> - -<A NAME="IDX1493"></A> -</P> -<DL> -<DT><U>Function:</U> <B>proper-list?</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1494"></A> -</P> -<DL> -<DT><U>Function:</U> <B>circular-list?</B> <I>x</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1495"></A> -</P> -<DL> -<DT><U>Function:</U> <B>dotted-list?</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1496"></A> -</P> -<DL> -<DT><U>Function:</U> <B>null-list?</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1497"></A> -</P> -<DL> -<DT><U>Function:</U> <B>not-pair?</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1498"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list=</B> <I>=pred list <small>...</small></I> -<DD><P> - -</P> -</DL> -<A NAME="SEC252"></A> -<H3> Selectors </H3> -<!--docid::SEC252::--> -<P> - -<A NAME="IDX1499"></A> -</P> -<DL> -<DT><U>Function:</U> <B>first</B> <I>pair</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1500"></A> -</P> -<DL> -<DT><U>Function:</U> <B>second</B> <I>pair</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1501"></A> -</P> -<DL> -<DT><U>Function:</U> <B>third</B> <I>pair</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1502"></A> -</P> -<DL> -<DT><U>Function:</U> <B>fourth</B> <I>pair</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1503"></A> -</P> -<DL> -<DT><U>Function:</U> <B>fifth</B> <I>pair</I> -<DD><A NAME="IDX1504"></A> -<DT><U>Function:</U> <B>sixth</B> <I>obj</I> -<DD><A NAME="IDX1505"></A> -<DT><U>Function:</U> <B>seventh</B> <I>obj</I> -<DD><A NAME="IDX1506"></A> -<DT><U>Function:</U> <B>eighth</B> <I>obj</I> -<DD><A NAME="IDX1507"></A> -<DT><U>Function:</U> <B>ninth</B> <I>obj</I> -<DD><A NAME="IDX1508"></A> -<DT><U>Function:</U> <B>tenth</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1509"></A> -</P> -<DL> -<DT><U>Function:</U> <B>car+cdr</B> <I>pair</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1510"></A> -</P> -<DL> -<DT><U>Function:</U> <B>drop</B> <I>lst k</I> -<DD><A NAME="IDX1511"></A> -<DT><U>Function:</U> <B>take</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1512"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>take!</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1513"></A> -</P> -<DL> -<DT><U>Function:</U> <B>take-right</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1514"></A> -</P> -<DL> -<DT><U>Function:</U> <B>drop-right</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1515"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>drop-right!</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1516"></A> -</P> -<DL> -<DT><U>Function:</U> <B>split-at</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1517"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>split-at!</B> <I>lst k</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1518"></A> -</P> -<DL> -<DT><U>Function:</U> <B>last</B> <I>lst</I> -<DD><P> - -(car (last-pair lst)) -</P> -</DL> -<A NAME="SEC253"></A> -<H3> Miscellaneous </H3> -<!--docid::SEC253::--> -<P> - -<A NAME="IDX1519"></A> -</P> -<DL> -<DT><U>Function:</U> <B>length+</B> <I>obj</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1520"></A> -</P> -<DL> -<DT><U>Function:</U> <B>concatenate</B> <I>lists</I> -<DD><A NAME="IDX1521"></A> -<DT><U>Function:</U> <B>concatenate!</B> <I>lists</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1522"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>reverse!</B> <I>lst</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1523"></A> -</P> -<DL> -<DT><U>Function:</U> <B>append-reverse</B> <I>rev-head tail</I> -<DD><A NAME="IDX1524"></A> -<DT><U>Function:</U> <B>append-reverse!</B> <I>rev-head tail</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1525"></A> -</P> -<DL> -<DT><U>Function:</U> <B>zip</B> <I>list1 list2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1526"></A> -</P> -<DL> -<DT><U>Function:</U> <B>unzip1</B> <I>lst</I> -<DD><A NAME="IDX1527"></A> -<DT><U>Function:</U> <B>unzip2</B> <I>lst</I> -<DD><A NAME="IDX1528"></A> -<DT><U>Function:</U> <B>unzip3</B> <I>lst</I> -<DD><A NAME="IDX1529"></A> -<DT><U>Function:</U> <B>unzip4</B> <I>lst</I> -<DD><A NAME="IDX1530"></A> -<DT><U>Function:</U> <B>unzip5</B> <I>lst</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1531"></A> -</P> -<DL> -<DT><U>Function:</U> <B>count</B> <I>pred list1 list2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<A NAME="SEC254"></A> -<H3> Fold and Unfold </H3> -<!--docid::SEC254::--> -<P> - -<A NAME="IDX1532"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>map!</B> <I>f list1 clist2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1533"></A> -</P> -<DL> -<DT><U>Function:</U> <B>pair-for-each</B> <I>f clist1 clist2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<A NAME="SEC255"></A> -<H3> Filtering and Partitioning </H3> -<!--docid::SEC255::--> -<P> - -<A NAME="IDX1534"></A> -</P> -<DL> -<DT><U>Function:</U> <B>filter</B> <I>pred lis</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1535"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>filter!</B> <I>pred l</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1536"></A> -</P> -<DL> -<DT><U>Function:</U> <B>partition</B> <I>pred list</I> -<DD><P> - -</P> -</DL> -<A NAME="SEC256"></A> -<H3> Searching </H3> -<!--docid::SEC256::--> -<P> - -<A NAME="IDX1537"></A> -</P> -<DL> -<DT><U>Function:</U> <B>find</B> <I>pred list</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1538"></A> -</P> -<DL> -<DT><U>Function:</U> <B>find-tail</B> <I>pred list</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1539"></A> -</P> -<DL> -<DT><U>Function:</U> <B>remove</B> <I>pred l</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1540"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>remove!</B> <I>pred l</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1541"></A> -</P> -<DL> -<DT><U>Function:</U> <B>any</B> <I>pred clist1 clist2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1542"></A> -</P> -<DL> -<DT><U>Function:</U> <B>list-index</B> <I>pred clist1 clist2 <small>...</small></I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1543"></A> -</P> -<DL> -<DT><U>Function:</U> <B>span</B> <I>pred list</I> -<DD><P> - -</P> -</DL> -<P> - -<A NAME="IDX1544"></A> -</P> -<DL> -<DT><U>Function:</U> <B>member</B> <I>obj list pred</I> -<DD><P> - -<A NAME="IDX1545"></A> -<DT><U>Function:</U> <B>member</B> <I>obj list</I> -<DD></P> -<P> - -<CODE>member</CODE> returns the first sublist of <VAR>list</VAR> whose car is <VAR>obj</VAR>, where the sublists -of <VAR>list</VAR> are the non-empty lists returned by <TT>(list-tail <VAR>list</VAR> <VAR>k</VAR>)</TT> -for <VAR>k</VAR> less than the length of <VAR>list</VAR>. If <VAR>obj</VAR> does not occur in <VAR>list</VAR>, -then <TT>#f</TT> (not the empty list) is returned. The procedure <VAR>pred</VAR> is -used for testing equality. If <VAR>pred</VAR> is not provided, `<SAMP>equal?</SAMP>' is -used. -</P> -</DL> -<A NAME="SEC257"></A> -<H3> Deleting </H3> -<!--docid::SEC257::--> -<P> - -<A NAME="SEC258"></A> -<H3> Association lists </H3> -<!--docid::SEC258::--> -<P> - -<A NAME="IDX1546"></A> -</P> -<DL> -<DT><U>Function:</U> <B>assoc</B> <I>obj alist pred</I> -<DD><P> - -<A NAME="IDX1547"></A> -<DT><U>Function:</U> <B>assoc</B> <I>obj alist</I> -<DD></P> -<P> - -<VAR>alist</VAR> (for "association list") must be a list of pairs. These -procedures find the first pair in <VAR>alist</VAR> whose car field is <VAR>obj</VAR>, and -returns that pair. If no pair in <VAR>alist</VAR> has <VAR>obj</VAR> as its car, then <TT>#f</TT> -(not the empty list) is returned. The procedure <VAR>pred</VAR> is used for -testing equality. If <VAR>pred</VAR> is not provided, `<SAMP>equal?</SAMP>' is used. -</P> -</DL> -<A NAME="SEC259"></A> -<H3> Set operations </H3> -<!--docid::SEC259::--> -<P> - -<A NAME="SRFI-2"></A> -<HR SIZE="6"> -<A NAME="SEC260"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC249"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC261"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.4.13.2 SRFI-2 </H4> -<!--docid::SEC260::--> -<P> - -<CODE>(require 'srfi-2)</CODE> -<A NAME="IDX1548"></A> -</P> -<P> - -<A NAME="IDX1549"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>and-let*</B> <I>claws body <small>...</small></I> -<DD><P> - -<A HREF="http://srfi.schemers.org/srfi-2/srfi-2.html">http://srfi.schemers.org/srfi-2/srfi-2.html</A> -</P> -</DL> -<P> - -<A NAME="SRFI-8"></A> -<HR SIZE="6"> -<A NAME="SEC261"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC260"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC262"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.4.13.3 SRFI-8 </H4> -<!--docid::SEC261::--> -<P> - -<CODE>(require 'srfi-8)</CODE> -<A NAME="IDX1550"></A> -</P> -<P> - -<A NAME="IDX1551"></A> -</P> -<DL> -<DT><U>Special Form:</U> <B>receive</B> <I>formals expression body <small>...</small></I> -<DD><P> - -<A HREF="http://srfi.schemers.org/srfi-8/srfi-8.html">http://srfi.schemers.org/srfi-8/srfi-8.html</A> -</P> -</DL> -<P> - -<A NAME="SRFI-9"></A> -<HR SIZE="6"> -<A NAME="SEC262"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC261"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC248"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H4> 7.4.13.4 SRFI-9 </H4> -<!--docid::SEC262::--> -<P> - -<CODE>(require 'srfi-9)</CODE> -<A NAME="IDX1552"></A> -</P> -<P> - -<A HREF="http://srfi.schemers.org/srfi-9/srfi-9.html">http://srfi.schemers.org/srfi-9/srfi-9.html</A> -</P> -<P> - -<A NAME="IDX1553"></A> -</P> -<DL> -<DT><U>Special Form:</U> <B>define-record-type</B> <I><type-name> (<constructor-name> <field-tag> ...) <predicate-name> <field spec> ...</I> -<DD><P> - -Where -<TABLE><tr><td> </td><td class=example><pre><field-spec> == (<field-tag> <accessor-name>) - == (<field-tag> <accessor-name> <modifier-name>) - -</pre></td></tr></table><P> - -<CODE>define-record-type</CODE> is a syntax wrapper for the SLIB -<CODE>record</CODE> module. -</P> -</DL> -<P> - -<A NAME="Session Support"></A> -<HR SIZE="6"> -<A NAME="SEC263"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC262"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC264"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.5 Session Support </H2> -<!--docid::SEC263::--> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC264">7.5.1 Repl</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Macros at top-level</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC265">7.5.2 Quick Print</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Loop-safe Output</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC266">7.5.3 Debug</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">To err is human ...</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC267">7.5.4 Breakpoints</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Pause execution</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC268">7.5.5 Tracing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">'trace</TD></TR> -</TABLE> -<P> - -<A NAME="Repl"></A> -<HR SIZE="6"> -<A NAME="SEC264"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC265"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.5.1 Repl </H3> -<!--docid::SEC264::--> -<P> - -<CODE>(require 'repl)</CODE> -<A NAME="IDX1554"></A> -</P> -<P> - -Here is a read-eval-print-loop which, given an eval, evaluates forms. -</P> -<P> - -<A NAME="IDX1555"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>repl:top-level</B> <I>repl:eval</I> -<DD><CODE>read</CODE>s, <CODE>repl:eval</CODE>s and <CODE>write</CODE>s expressions from -<CODE>(current-input-port)</CODE> to <CODE>(current-output-port)</CODE> until an -end-of-file is encountered. <CODE>load</CODE>, <CODE>slib:eval</CODE>, -<CODE>slib:error</CODE>, and <CODE>repl:quit</CODE> dynamically bound during -<CODE>repl:top-level</CODE>. -</DL> -<P> - -<A NAME="IDX1556"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>repl:quit</B> -<DD>Exits from the invocation of <CODE>repl:top-level</CODE>. -</DL> -<P> - -The <CODE>repl:</CODE> procedures establish, as much as is possible to do -portably, a top level environment supporting macros. -<CODE>repl:top-level</CODE> uses <CODE>dynamic-wind</CODE> to catch error conditions -and interrupts. If your implementation supports this you are all set. -</P> -<P> - -Otherwise, if there is some way your implementation can catch error -conditions and interrupts, then have them call <CODE>slib:error</CODE>. It -will display its arguments and reenter <CODE>repl:top-level</CODE>. -<CODE>slib:error</CODE> dynamically bound by <CODE>repl:top-level</CODE>. -</P> -<P> - -To have your top level loop always use macros, add any interrupt -catching lines and the following lines to your Scheme init file: -<TABLE><tr><td> </td><td class=example><pre>(require 'macro) -<A NAME="IDX1557"></A>(require 'repl) -<A NAME="IDX1558"></A>(repl:top-level macro:eval) -</pre></td></tr></table><P> - -<A NAME="Quick Print"></A> -<HR SIZE="6"> -<A NAME="SEC265"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC264"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC266"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.5.2 Quick Print </H3> -<!--docid::SEC265::--> -<P> - -<CODE>(require 'qp)</CODE> -<A NAME="IDX1559"></A> -</P> -<P> - -When displaying error messages and warnings, it is paramount that the -output generated for circular lists and large data structures be -limited. This section supplies a procedure to do this. It could be -much improved. -</P> -<P> - -<BLOCKQUOTE> -Notice that the neccessity for truncating output eliminates -Common-Lisp's <A HREF="slib_4.html#SEC53">4.2 Format (version 3.0)</A> from consideration; even when variables -<CODE>*print-level*</CODE> and <CODE>*print-level*</CODE> are set, huge strings and -bit-vectors are <EM>not</EM> limited. -</BLOCKQUOTE> -<P> - -<A NAME="IDX1560"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>qp</B> <I>arg1 <small>...</small></I> -<DD><A NAME="IDX1561"></A> -<DT><U>Procedure:</U> <B>qpn</B> <I>arg1 <small>...</small></I> -<DD><A NAME="IDX1562"></A> -<DT><U>Procedure:</U> <B>qpr</B> <I>arg1 <small>...</small></I> -<DD><CODE>qp</CODE> writes its arguments, separated by spaces, to -<CODE>(current-output-port)</CODE>. <CODE>qp</CODE> compresses printing by -substituting `<SAMP>...</SAMP>' for substructure it does not have sufficient -room to print. <CODE>qpn</CODE> is like <CODE>qp</CODE> but outputs a newline -before returning. <CODE>qpr</CODE> is like <CODE>qpn</CODE> except that it returns -its last argument. -</DL> -<P> - -<A NAME="IDX1563"></A> -</P> -<DL> -<DT><U>Variable:</U> <B>*qp-width*</B> -<DD><VAR>*qp-width*</VAR> is the largest number of characters that <CODE>qp</CODE> -should use. If <VAR>*qp-width*</VAR> is #f, then all items will be -<CODE>write</CODE>n. If <VAR>*qp-width*</VAR> is 0, then all items except -procedures will be <CODE>write</CODE>n; procedures will be indicated by -`<SAMP>#[proc]</SAMP>'. -</DL> -<P> - -<A NAME="Debug"></A> -<HR SIZE="6"> -<A NAME="SEC266"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC265"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC267"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.5.3 Debug </H3> -<!--docid::SEC266::--> -<P> - -<CODE>(require 'debug)</CODE> -<A NAME="IDX1564"></A> -</P> -<P> - -Requiring <CODE>debug</CODE> automatically requires <CODE>trace</CODE> and -<CODE>break</CODE>. -</P> -<P> - -An application with its own datatypes may want to substitute its own -printer for <CODE>qp</CODE>. This example shows how to do this: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define qpn (lambda args) <small>...</small>) -(provide 'qp) -(require 'debug) -<A NAME="IDX1565"></A></pre></td></tr></table><P> - -<A NAME="IDX1566"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>trace-all</B> <I>file <small>...</small></I> -<DD>Traces (see section <A HREF="slib_7.html#SEC268">7.5.5 Tracing</A>) all procedures <CODE>define</CODE>d at top-level in -`<TT>file</TT>' <small>...</small>. -<P> - -<A NAME="IDX1567"></A> -<DT><U>Procedure:</U> <B>track-all</B> <I>file <small>...</small></I> -<DD>Tracks (see section <A HREF="slib_7.html#SEC268">7.5.5 Tracing</A>) all procedures <CODE>define</CODE>d at top-level in -`<TT>file</TT>' <small>...</small>. -</P> -<P> - -<A NAME="IDX1568"></A> -<DT><U>Procedure:</U> <B>stack-all</B> <I>file <small>...</small></I> -<DD>Stacks (see section <A HREF="slib_7.html#SEC268">7.5.5 Tracing</A>) all procedures <CODE>define</CODE>d at top-level in -`<TT>file</TT>' <small>...</small>. -</P> -</DL> -<P> - -<A NAME="IDX1569"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>break-all</B> <I>file <small>...</small></I> -<DD>Breakpoints (see section <A HREF="slib_7.html#SEC267">7.5.4 Breakpoints</A>) all procedures <CODE>define</CODE>d at -top-level in `<TT>file</TT>' <small>...</small>. -</DL> -<P> - -<A NAME="Breakpoints"></A> -<HR SIZE="6"> -<A NAME="SEC267"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC266"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC268"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.5.4 Breakpoints </H3> -<!--docid::SEC267::--> -<P> - -<CODE>(require 'break)</CODE> -<A NAME="IDX1570"></A> -</P> -<P> - -<A NAME="IDX1571"></A> -</P> -<DL> -<DT><U>Function:</U> <B>init-debug</B> -<DD>If your Scheme implementation does not support <CODE>break</CODE> or -<CODE>abort</CODE>, a message will appear when you <CODE>(require 'break)</CODE> or -<A NAME="IDX1572"></A> -<CODE>(require 'debug)</CODE> telling you to type <CODE>(init-debug)</CODE>. This -<A NAME="IDX1573"></A> -is in order to establish a top-level continuation. Typing -<CODE>(init-debug)</CODE> at top level sets up a continuation for -<CODE>break</CODE>. -</DL> -<P> - -<A NAME="IDX1574"></A> -</P> -<DL> -<DT><U>Function:</U> <B>breakpoint</B> <I>arg1 <small>...</small></I> -<DD>Returns from the top level continuation and pushes the continuation from -which it was called on a continuation stack. -</DL> -<P> - -<A NAME="IDX1575"></A> -</P> -<DL> -<DT><U>Function:</U> <B>continue</B> -<DD>Pops the topmost continuation off of the continuation stack and returns -an unspecified value to it. -<P> - -<A NAME="IDX1576"></A> -<DT><U>Function:</U> <B>continue</B> <I>arg1 <small>...</small></I> -<DD>Pops the topmost continuation off of the continuation stack and returns -<VAR>arg1</VAR> <small>...</small> to it. -</P> -</DL> -<P> - -<A NAME="IDX1577"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>break</B> <I>proc1 <small>...</small></I> -<DD>Redefines the top-level named procedures given as arguments so that -<CODE>breakpoint</CODE> is called before calling <VAR>proc1</VAR> <small>...</small>. -<A NAME="IDX1578"></A> -<DT><U>Macro:</U> <B>break</B> -<DD>With no arguments, makes sure that all the currently broken identifiers -are broken (even if those identifiers have been redefined) and returns a -list of the broken identifiers. -</DL> -<P> - -<A NAME="IDX1579"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>unbreak</B> <I>proc1 <small>...</small></I> -<DD>Turns breakpoints off for its arguments. -<A NAME="IDX1580"></A> -<DT><U>Macro:</U> <B>unbreak</B> -<DD>With no arguments, unbreaks all currently broken identifiers and returns -a list of these formerly broken identifiers. -</DL> -<P> - -These are <EM>procedures</EM> for breaking. If defmacros are not natively -supported by your implementation, these might be more convenient to use. -</P> -<P> - -<A NAME="IDX1581"></A> -</P> -<DL> -<DT><U>Function:</U> <B>breakf</B> <I>proc</I> -<DD><A NAME="IDX1582"></A> -<DT><U>Function:</U> <B>breakf</B> <I>proc name</I> -<DD>To break, type -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (breakf <VAR>symbol</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (breakf <VAR>symbol</VAR> '<VAR>symbol</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(define <VAR>symbol</VAR> (breakf <VAR>function</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(define <VAR>symbol</VAR> (breakf <VAR>function</VAR> '<VAR>symbol</VAR>)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1583"></A> -</P> -<DL> -<DT><U>Function:</U> <B>unbreakf</B> <I>proc</I> -<DD>To unbreak, type -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (unbreakf <VAR>symbol</VAR>)) -</pre></td></tr></table></DL> -<P> - -<A NAME="Trace"></A> -<HR SIZE="6"> -<A NAME="SEC268"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC267"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC269"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC263"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.5.5 Tracing </H3> -<!--docid::SEC268::--> -<P> - -<CODE>(require 'trace)</CODE> -<A NAME="IDX1584"></A> -</P> -<P> - -This feature provides three ways to monitor procedure invocations: -</P> -<P> - -</P> -<DL COMPACT> -<DT>stack -<DD>Pushes the procedure-name when the procedure is called; pops when it -returns. -<DT>track -<DD>Pushes the procedure-name and arguments when the procedure is called; -pops when it returns. -<DT>trace -<DD>Pushes the procedure-name and prints `<SAMP>CALL <VAR>procedure-name</VAR> -<VAR>arg1</VAR> <small>...</small></SAMP>' when the procdure is called; pops and prints -`<SAMP>RETN <VAR>procedure-name</VAR> <VAR>value</VAR></SAMP>' when the procedure returns. -</DL> -<P> - -<A NAME="IDX1585"></A> -</P> -<DL> -<DT><U>Variable:</U> <B>debug:max-count</B> -<DD>If a traced procedure calls itself or untraced procedures which call it, -stack, track, and trace will limit the number of stack pushes to -<VAR>debug:max-count</VAR>. -</DL> -<P> - -<A NAME="IDX1586"></A> -</P> -<DL> -<DT><U>Function:</U> <B>print-call-stack</B> -<DD><A NAME="IDX1587"></A> -<DT><U>Function:</U> <B>print-call-stack</B> <I>port</I> -<DD>Prints the call-stack to <VAR>port</VAR> or the current-error-port. -</DL> -<P> - -<A NAME="IDX1588"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>trace</B> <I>proc1 <small>...</small></I> -<DD>Traces the top-level named procedures given as arguments. -<A NAME="IDX1589"></A> -<DT><U>Macro:</U> <B>trace</B> -<DD>With no arguments, makes sure that all the currently traced identifiers -are traced (even if those identifiers have been redefined) and returns a -list of the traced identifiers. -</DL> -<P> - -<A NAME="IDX1590"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>track</B> <I>proc1 <small>...</small></I> -<DD>Traces the top-level named procedures given as arguments. -<A NAME="IDX1591"></A> -<DT><U>Macro:</U> <B>track</B> -<DD>With no arguments, makes sure that all the currently tracked identifiers -are tracked (even if those identifiers have been redefined) and returns -a list of the tracked identifiers. -</DL> -<P> - -<A NAME="IDX1592"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>stack</B> <I>proc1 <small>...</small></I> -<DD>Traces the top-level named procedures given as arguments. -<A NAME="IDX1593"></A> -<DT><U>Macro:</U> <B>stack</B> -<DD>With no arguments, makes sure that all the currently stacked identifiers -are stacked (even if those identifiers have been redefined) and returns -a list of the stacked identifiers. -</DL> -<P> - -<A NAME="IDX1594"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>untrace</B> <I>proc1 <small>...</small></I> -<DD>Turns tracing, tracking, and off for its arguments. -<A NAME="IDX1595"></A> -<DT><U>Macro:</U> <B>untrace</B> -<DD>With no arguments, untraces all currently traced identifiers and returns -a list of these formerly traced identifiers. -</DL> -<P> - -<A NAME="IDX1596"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>untrack</B> <I>proc1 <small>...</small></I> -<DD>Turns tracing, tracking, and off for its arguments. -<A NAME="IDX1597"></A> -<DT><U>Macro:</U> <B>untrack</B> -<DD>With no arguments, untracks all currently tracked identifiers and returns -a list of these formerly tracked identifiers. -</DL> -<P> - -<A NAME="IDX1598"></A> -</P> -<DL> -<DT><U>Macro:</U> <B>unstack</B> <I>proc1 <small>...</small></I> -<DD>Turns tracing, stacking, and off for its arguments. -<A NAME="IDX1599"></A> -<DT><U>Macro:</U> <B>unstack</B> -<DD>With no arguments, unstacks all currently stacked identifiers and returns -a list of these formerly stacked identifiers. -</DL> -<P> - -These are <EM>procedures</EM> for tracing. If defmacros are not natively -supported by your implementation, these might be more convenient to use. -</P> -<P> - -<A NAME="IDX1600"></A> -</P> -<DL> -<DT><U>Function:</U> <B>tracef</B> <I>proc</I> -<DD><A NAME="IDX1601"></A> -<DT><U>Function:</U> <B>tracef</B> <I>proc name</I> -<DD><A NAME="IDX1602"></A> -<DT><U>Function:</U> <B>trackf</B> <I>proc</I> -<DD><A NAME="IDX1603"></A> -<DT><U>Function:</U> <B>trackf</B> <I>proc name</I> -<DD><A NAME="IDX1604"></A> -<DT><U>Function:</U> <B>stackf</B> <I>proc</I> -<DD><A NAME="IDX1605"></A> -<DT><U>Function:</U> <B>stackf</B> <I>proc name</I> -<DD>To trace, type -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (tracef <VAR>symbol</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (tracef <VAR>symbol</VAR> '<VAR>symbol</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(define <VAR>symbol</VAR> (tracef <VAR>function</VAR>)) -</pre></td></tr></table>or -<TABLE><tr><td> </td><td class=example><pre>(define <VAR>symbol</VAR> (tracef <VAR>function</VAR> '<VAR>symbol</VAR>)) -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX1606"></A> -</P> -<DL> -<DT><U>Function:</U> <B>untracef</B> <I>proc</I> -<DD>Removes tracing, tracking, or stacking for <VAR>proc</VAR>. -To untrace, type -<TABLE><tr><td> </td><td class=example><pre>(set! <VAR>symbol</VAR> (untracef <VAR>symbol</VAR>)) -</pre></td></tr></table></DL> -<P> - -<A NAME="System Interface"></A> -<HR SIZE="6"> -<A NAME="SEC269"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC268"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC270"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.6 System Interface </H2> -<!--docid::SEC269::--> -<P> - -If <CODE>(provided? 'getenv)</CODE>: -</P> -<P> - -<A NAME="IDX1607"></A> -</P> -<DL> -<DT><U>Function:</U> <B>getenv</B> <I>name</I> -<DD>Looks up <VAR>name</VAR>, a string, in the program environment. If <VAR>name</VAR> is -found a string of its value is returned. Otherwise, <CODE>#f</CODE> is returned. -</DL> -<P> - -If <CODE>(provided? 'system)</CODE>: -</P> -<P> - -<A NAME="IDX1608"></A> -</P> -<DL> -<DT><U>Function:</U> <B>system</B> <I>command-string</I> -<DD>Executes the <VAR>command-string</VAR> on the computer and returns the -integer status code. -</DL> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC270">7.6.1 Directories</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC271">7.6.2 Transactions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_7.html#SEC275">7.6.3 CVS</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -</TABLE> -<P> - -<A NAME="Directories"></A> -<HR SIZE="6"> -<A NAME="SEC270"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC269"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC271"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC269"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.6.1 Directories </H3> -<!--docid::SEC270::--> -<P> - -<CODE>(require 'directory)</CODE> -<A NAME="IDX1609"></A> -</P> -<P> - -<A NAME="IDX1610"></A> -</P> -<DL> -<DT><U>Function:</U> <B>current-directory</B> -<DD><P> - -<CODE>current-directory</CODE> returns a string containing the absolute file -name representing the current working directory. If this string -cannot be obtained, #f is returned. -</P> -<P> - -If <CODE>current-directory</CODE> cannot be supported by the platform, then #f is returned. -</P> -</DL> -<P> - -<A NAME="IDX1611"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-directory</B> <I>name</I> -<DD><P> - -Creates a sub-directory <VAR>name</VAR> of the current-directory. If -successful, <CODE>make-directory</CODE> returns #t; otherwise #f. -</P> -</DL> -<P> - -<A NAME="IDX1612"></A> -</P> -<DL> -<DT><U>Function:</U> <B>directory-for-each</B> <I>proc directory</I> -<DD><P> - -<VAR>proc</VAR> must be a procedure taking one argument. -`<SAMP>Directory-For-Each</SAMP>' applies <VAR>proc</VAR> to the (string) name of -each file in <VAR>directory</VAR>. The dynamic order in which <VAR>proc</VAR> is -applied to the filenames is unspecified. The value returned by -`<SAMP>directory-for-each</SAMP>' is unspecified. -</P> -<P> - -<A NAME="IDX1613"></A> -<DT><U>Function:</U> <B>directory-for-each</B> <I>proc directory pred</I> -<DD>Applies <VAR>proc</VAR> only to those filenames for which the procedure -<VAR>pred</VAR> returns a non-false value. -</P> -<P> - -<A NAME="IDX1614"></A> -<DT><U>Function:</U> <B>directory-for-each</B> <I>proc directory match</I> -<DD>Applies <VAR>proc</VAR> only to those filenames for which -<CODE>(filename:match?? <VAR>match</VAR>)</CODE> would return a non-false value -(see section `Filenames' in <CITE>SLIB</CITE>). -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(require 'directory) -(directory-for-each print "." "[A-Z]*.scm") --| -"Bev2slib.scm" -"Template.scm" -</pre></td></tr></table></DL> -<P> - -<A NAME="Transactions"></A> -<HR SIZE="6"> -<A NAME="SEC271"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC270"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC275"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC269"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.6.2 Transactions </H3> -<!--docid::SEC271::--> -<P> - -If <CODE>system</CODE> is provided by the Scheme implementation, the -<EM>transact</EM> package provides functions for file-locking and -file-replacement transactions. -</P> -<P> - -<CODE>(require 'transact)</CODE> -<A NAME="IDX1615"></A> -</P> -<P> - -<A NAME="SEC272"></A> -<H4> File Locking </H4> -<!--docid::SEC272::--> -<P> - -Unix file-locking is focussed on write permissions for segments of a -existing file. While this might be employed for (binary) database -access, it is not used for everyday contention (between users) for -text files. -</P> -<P> - -Microsoft has several file-locking protocols. Their model denies -write access to a file if any reader has it open. This is too -restrictive. Write access is denied even when the reader has -reached end-of-file. And tracking read access (which is much more -common than write access) causes havoc when remote hosts crash or -disconnect. -</P> -<P> - -It is bizarre that the concept of multi-user contention for -modifying files has not been adequately addressed by either of the -large operating system development efforts. There is further irony -that both camps support contention detection and resolution only -through weak conventions of some their document editing programs. -</P> -<P> - -<A NAME="IDX1616"></A> -The <EM>file-lock</EM> procedures implement a transaction method for file -<A NAME="IDX1617"></A> -replacement compatible with the methods used by the GNU <EM>emacs</EM> -<A NAME="IDX1618"></A> -text editor on Unix systems and the Microsoft <EM>Word</EM> editor. -<A NAME="IDX1619"></A> -<A NAME="IDX1620"></A> -</P> -<P> - -<A NAME="IDX1621"></A> -Both protocols employ what I term a <EM>certificate</EM> containing the -<A NAME="IDX1622"></A> -user, hostname, time, and (on Unix) process-id. -Intent to replace <VAR>file</VAR> is indicated by adding to <VAR>file</VAR>'s -directory a certificate object whose name is derived from -<VAR>file</VAR>. -</P> -<P> - -The Microsoft Word certificate is contained in a 162 byte file named -for the visited <VAR>file</VAR> with a `<SAMP>~$</SAMP>' prefix. -Emacs/Unix creates a symbolic link to a certificate named for the -visited <VAR>file</VAR> prefixed with `<SAMP>.#</SAMP>'. -Because Unix systems can import Microsoft file systems, these -routines maintain and check both Emacs and Word certificates. -</P> -<P> - -<A NAME="IDX1623"></A> -</P> -<DL> -<DT><U>Function:</U> <B>file-lock-owner</B> <I>path</I> -<DD><P> - -Returns the string `<SAMP><VAR>user</VAR>@<VAR>hostname</VAR></SAMP>' associated with -the lock owner of file <VAR>path</VAR> if locked; and #f otherwise. -</P> -</DL> -<P> - -<A NAME="IDX1624"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>file-lock!</B> <I>path email</I> -<DD><P> - -<A NAME="IDX1625"></A> -<DT><U>Procedure:</U> <B>file-lock!</B> <I>path</I> -<DD></P> -<P> - -<VAR>path</VAR> must be a string naming the file to be locked. If supplied, <VAR>email</VAR> -must be a string formatted as `<SAMP><VAR>user</VAR>@<VAR>hostname</VAR></SAMP>'. If -absent, <VAR>email</VAR> defaults to the value returned by <CODE>user-email-address</CODE>. -</P> -<P> - -If <VAR>path</VAR> is already locked, then <CODE>file-lock!</CODE> returns `<SAMP>#f</SAMP>'. If <VAR>path</VAR> is -unlocked, then <CODE>file-lock!</CODE> returns the certificate string associated with the -new lock for file <VAR>path</VAR>. -</P> -</DL> -<P> - -<A NAME="IDX1626"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>file-unlock!</B> <I>path certificate</I> -<DD><P> - -<VAR>path</VAR> must be a string naming the file to be unlocked. <VAR>certificate</VAR> must be the -string returned by <CODE>file-lock!</CODE> for <VAR>path</VAR>. -</P> -<P> - -If <VAR>path</VAR> is locked with <VAR>certificate</VAR>, then <CODE>file-unlock!</CODE> removes the locks and returns -`<SAMP>#t</SAMP>'. Otherwise, <CODE>file-unlock!</CODE> leaves the file system unaltered and returns -`<SAMP>#f</SAMP>'. -</P> -</DL> -<A NAME="SEC273"></A> -<H4> File Transactions </H4> -<!--docid::SEC273::--> -<P> - -<A NAME="IDX1627"></A> -</P> -<DL> -<DT><U>Function:</U> <B>emacs:backup-name</B> <I>path backup-style</I> -<DD><P> - -<VAR>path</VAR> must be a string. <VAR>backup-style</VAR> must be a symbol. Depending on <VAR>backup-style</VAR>, <CODE>emacs:backup-name</CODE> -returns: -</P> -<DL COMPACT> -<DT>none -<DD>#f -<DT>simple -<DD>the string "<VAR>path</VAR>~" -<DT>numbered -<DD>the string "<VAR>path</VAR>.~<VAR>n</VAR>~", where <VAR>n</VAR> is one greater than the -highest number appearing in a filename matching "<VAR>path</VAR>.~*~". <VAR>n</VAR> -defauls to 1 when no filename matches. -<DT>existing -<DD>the string "<VAR>path</VAR>.~<VAR>n</VAR>~" if a numbered backup already exists in -this directory; otherwise. "<VAR>path</VAR>~" -<DT>orig -<DD>the string "<VAR>path</VAR>.orig" -<DT>bak -<DD>the string "<VAR>path</VAR>.bak" -</DL> -</DL> -<P> - -<A NAME="IDX1628"></A> -</P> -<DL> -<DT><U>Function:</U> <B>transact-file-replacement</B> <I>proc path backup-style certificate</I> -<DD><P> - -<A NAME="IDX1629"></A> -<DT><U>Function:</U> <B>transact-file-replacement</B> <I>proc path backup-style</I> -<DD></P> -<P> - -<A NAME="IDX1630"></A> -<DT><U>Function:</U> <B>transact-file-replacement</B> <I>proc path</I> -<DD></P> -<P> - -<VAR>path</VAR> must be a string naming an existing file. <VAR>backup-style</VAR> is one of the -symbols none, simple, numbered, existing, orig, -bak or #f; with meanings described above; or a string naming -the location of a backup file. <VAR>backup-style</VAR> defaults to #f. If supplied, -<VAR>certificate</VAR> is the certificate with which <VAR>path</VAR> is locked. -</P> -<P> - -<VAR>proc</VAR> must be a procedure taking two string arguments: -<UL> -<LI> -<VAR>path</VAR>, the original filename (to be read); and -<LI> -a temporary file-name. -</UL> -<P> - -If <VAR>path</VAR> is locked by other than <VAR>certificate</VAR>, or if <VAR>certificate</VAR> is supplied and <VAR>path</VAR> is not -locked, then <CODE>transact-file-replacement</CODE> returns #f. If <VAR>certificate</VAR> is not supplied, then, <CODE>transact-file-replacement</CODE> creates -temporary (Emacs and Word) locks for <VAR>path</VAR> during the transaction. The -lock status of <VAR>path</VAR> will be restored before <CODE>transact-file-replacement</CODE> returns. -</P> -<P> - -<CODE>transact-file-replacement</CODE> calls <VAR>proc</VAR> with <VAR>path</VAR> (which should not be modified) and a temporary -file path to be written. -If <VAR>proc</VAR> returns any value other than #t, then the file named by <VAR>path</VAR> -is not altered and <CODE>transact-file-replacement</CODE> returns #f. -Otherwise, <CODE>emacs:backup-name</CODE> is called with <VAR>path</VAR> and <VAR>backup-style</VAR>. If it -returns a string, then <VAR>path</VAR> is renamed to it. -</P> -<P> - -Finally, the temporary file is renamed <VAR>path</VAR>. -<CODE>transact-file-replacement</CODE> returns #t if <VAR>path</VAR> was successfully replaced; and #f otherwise. -</P> -</DL> -<A NAME="SEC274"></A> -<H4> Identification </H4> -<!--docid::SEC274::--> -<P> - -<A NAME="IDX1631"></A> -</P> -<DL> -<DT><U>Function:</U> <B>user-email-address</B> -<DD><P> - -<CODE>user-email-address</CODE> returns a string of the form `<SAMP>username@hostname</SAMP>'. If -this e-mail address cannot be obtained, #f is returned. -</P> -</DL> -<P> - -<A NAME="CVS"></A> -<HR SIZE="6"> -<A NAME="SEC275"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC271"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC276"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC269"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H3> 7.6.3 CVS </H3> -<!--docid::SEC275::--> -<P> - -<CODE>(require 'cvs)</CODE> -<A NAME="IDX1632"></A> -</P> -<P> - -<A NAME="IDX1633"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cvs-files</B> <I>directory/</I> -<DD>Returns a list of the local pathnames (with prefix <VAR>directory/</VAR>) of all -CVS controlled files in <VAR>directory/</VAR> and in <VAR>directory/</VAR>'s subdirectories. -</DL> -<P> - -<A NAME="IDX1634"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cvs-directories</B> <I>directory/</I> -<DD>Returns a list of all of <VAR>directory/</VAR> and all <VAR>directory/</VAR>'s CVS controlled -subdirectories. -</DL> -<P> - -<A NAME="IDX1635"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cvs-root</B> <I>path/</I> -<DD>Returns the (string) contents of <VAR>path/</VAR>CVS/Root; -or <CODE>(getenv "CVSROOT")</CODE> if Root doesn't exist. -</DL> -<P> - -<A NAME="IDX1636"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cvs-repository</B> <I>directory/</I> -<DD>Returns the (string) contents of <VAR>directory/</VAR>CVS/Root appended -with <VAR>directory/</VAR>CVS/Repository; or #f if <VAR>directory/</VAR>CVS/Repository -doesn't exist. -</DL> -<P> - -<A NAME="IDX1637"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>cvs-set-root!</B> <I>new-root directory/</I> -<DD><P> - -Writes <VAR>new-root</VAR> to file CVS/Root of <VAR>directory/</VAR> and all its subdirectories. -</P> -</DL> -<P> - -<A NAME="IDX1638"></A> -</P> -<DL> -<DT><U>Function:</U> <B>cvs-vet</B> <I>directory/</I> -<DD><P> - -Signals an error if CVS/Repository or CVS/Root files in <VAR>directory/</VAR> or any -subdirectory do not match. -</P> -</DL> -<P> - -<A NAME="Extra-SLIB Packages"></A> -<HR SIZE="6"> -<A NAME="SEC276"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC275"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<H2> 7.7 Extra-SLIB Packages </H2> -<!--docid::SEC276::--> -<P> - -Several Scheme packages have been written using SLIB. There are several -reasons why a package might not be included in the SLIB distribution: -<UL> -<LI> -Because it requires special hardware or software which is not universal. -<LI> -Because it is large and of limited interest to most Scheme users. -<LI> -Because it has copying terms different enough from the other SLIB -packages that its inclusion would cause confusion. -<LI> -Because it is an application program, rather than a library module. -<LI> -Because I have been too busy to integrate it. -</UL> -<P> - -Once an optional package is installed (and an entry added to -<CODE>*catalog*</CODE>, the <CODE>require</CODE> mechanism allows it to be called up -and used as easily as any other SLIB package. Some optional packages -(for which <CODE>*catalog*</CODE> already has entries) available from SLIB -sites are: -</P> -<P> - -</P> -<DL COMPACT> -<DT>SLIB-PSD -<DD>is a portable debugger for Scheme (requires emacs editor). -<P> - -<A HREF="http://swissnet.ai.mit.edu/ftpdir/scm/slib-psd1-3.tar.gz"> -http://swissnet.ai.mit.edu/ftpdir/scm/slib-psd1-3.tar.gz -</A> -</P> -<P> - -swissnet.ai.mit.edu:/pub/scm/slib-psd1-3.tar.gz -</P> -<P> - -ftp.maths.tcd.ie:pub/bosullvn/jacal/slib-psd1-3.tar.gz -</P> -<P> - -ftp.cs.indiana.edu:/pub/scheme-repository/utl/slib-psd1-3.tar.gz -</P> -<P> - -With PSD, you can run a Scheme program in an Emacs buffer, set -breakpoints, single step evaluation and access and modify the program's -variables. It works by instrumenting the original source code, so it -should run with any R4RS compliant Scheme. It has been tested with SCM, -Elk 1.5, and the sci interpreter in the Scheme->C system, but should -work with other Schemes with a minimal amount of porting, if at -all. Includes documentation and user's manual. Written by Pertti -Kellom\"aki, pk @ cs.tut.fi. The Lisp Pointers article describing PSD -(Lisp Pointers VI(1):15-23, January-March 1993) is available as -<A HREF="http://www.cs.tut.fi/staff/pk/scheme/psd/article/article.html"> -http://www.cs.tut.fi/staff/pk/scheme/psd/article/article.html -</A> -</P> -<P> - -</P> -<DT>SCHELOG -<DD>is an embedding of Prolog in Scheme.<BR> -<A HREF="http://www.ccs.neu.edu/~dorai/schelog/schelog.html"> -http://www.ccs.neu.edu/~dorai/schelog/schelog.html -</A> -<P> - -</P> -<DT>JFILTER -<DD>is a Scheme program which converts text among the JIS, EUC, and -Shift-JIS Japanese character sets.<BR> -<A HREF="http://www.sci.toyama-u.ac.jp/~iwao/Scheme/Jfilter/index.html"> -http://www.sci.toyama-u.ac.jp/~iwao/Scheme/Jfilter/index.html -</A> -</DL> -<P> - -<A NAME="About SLIB"></A> -<HR SIZE="6"> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_7.html#SEC183"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_8.html#SEC277"> >> </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top">Top</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_toc.html#SEC_Contents">Contents</A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_abt.html#SEC_About"> ? </A>]</TD> -</TR></TABLE> -<BR> -<FONT SIZE="-1"> -This document was generated -by <I>Steve Langasek</I> on <I>January, 10 2005</I> -using <A HREF="http://texi2html.cvshome.org"><I>texi2html</I></A> -</FONT> - -</BODY> -</HTML> |