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diff --git a/slib_2.html b/slib_2.html deleted file mode 100644 index ef8c059..0000000 --- a/slib_2.html +++ /dev/null @@ -1,824 +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: Universal SLIB Procedures</TITLE> - -<META NAME="description" CONTENT="SLIB: Universal SLIB Procedures"> -<META NAME="keywords" CONTENT="SLIB: Universal SLIB Procedures"> -<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="SEC13"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC12"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC14"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib.html#SEC_Top"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2. Universal SLIB Procedures </H1> -<!--docid::SEC13::--> -<P> - -The procedures described in these sections are supported by all -implementations as part of the `<SAMP>*.init</SAMP>' files or by -`<TT>require.scm</TT>'. -</P> -<P> - -<TABLE BORDER="0" CELLSPACING="0"> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_2.html#SEC14">2.1 Vicinity</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Pathname Management</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_2.html#SEC15">2.2 Configuration</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Characteristics of Scheme Implementation</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_2.html#SEC16">2.3 Input/Output</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Things not provided by the Scheme specs.</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_2.html#SEC17">2.4 System</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">LOADing, EVALing, ERRORing, and EXITing</TD></TR> -<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_2.html#SEC18">2.5 Miscellany</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP"></TD></TR> -</TABLE> -<P> - -<A NAME="Vicinity"></A> -<HR SIZE="6"> -<A NAME="SEC14"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC15"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.1 Vicinity </H2> -<!--docid::SEC14::--> -<P> - -A vicinity is a descriptor for a place in the file system. Vicinities -hide from the programmer the concepts of host, volume, directory, and -version. Vicinities express only the concept of a file environment -where a file name can be resolved to a file in a system independent -manner. Vicinities can even be used on <EM>flat</EM> file systems (which -have no directory structure) by having the vicinity express constraints -on the file name. On most systems a vicinity would be a string. All of -these procedures are file system dependent. -</P> -<P> - -These procedures are provided by all implementations. -</P> -<P> - -<A NAME="IDX56"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-vicinity</B> <I>dirpath</I> -<DD>Returns <VAR>dirpath</VAR> as a vicinity for use as first argument to -<CODE>in-vicinity</CODE>. -</DL> -<P> - -<A NAME="IDX57"></A> -</P> -<DL> -<DT><U>Function:</U> <B>pathname->vicinity</B> <I>path</I> -<DD>Returns the vicinity containing <VAR>path</VAR>. -<TABLE><tr><td> </td><td class=example><pre>(pathname->vicinity "/usr/local/lib/scm/Link.scm") - => "/usr/local/lib/scm/" -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX58"></A> -</P> -<DL> -<DT><U>Function:</U> <B>program-vicinity</B> -<DD>Returns the vicinity of the currently loading Scheme code. For an -interpreter this would be the directory containing source code. For a -compiled system (with multiple files) this would be the directory where -the object or executable files are. If no file is currently loading it -the result is undefined. <STRONG>Warning:</STRONG> <CODE>program-vicinity</CODE> can -return incorrect values if your program escapes back into a -<CODE>load</CODE>. -</DL> -<P> - -<A NAME="IDX59"></A> -</P> -<DL> -<DT><U>Function:</U> <B>library-vicinity</B> -<DD>Returns the vicinity of the shared Scheme library. -</DL> -<P> - -<A NAME="IDX60"></A> -</P> -<DL> -<DT><U>Function:</U> <B>implementation-vicinity</B> -<DD>Returns the vicinity of the underlying Scheme implementation. This -vicinity will likely contain startup code and messages and a compiler. -</DL> -<P> - -<A NAME="IDX61"></A> -</P> -<DL> -<DT><U>Function:</U> <B>user-vicinity</B> -<DD>Returns the vicinity of the current directory of the user. On most -systems this is `<TT>""</TT>' (the empty string). -</DL> -<P> - -<A NAME="IDX62"></A> -</P> -<DL> -<DT><U>Function:</U> <B>home-vicinity</B> -<DD>Returns the vicinity of the user's <EM>HOME</EM> directory, the directory -<A NAME="IDX63"></A> -which typically contains files which customize a computer environment -for a user. If scheme is running without a user (eg. a daemon) or if -this concept is meaningless for the platform, then <CODE>home-vicinity</CODE> -returns <CODE>#f</CODE>. -</DL> -<P> - -<A NAME="IDX64"></A> -</P> -<DL> -<DT><U>Function:</U> <B>vicinity:suffix?</B> <I>chr</I> -<DD>Returns the `<SAMP>#t</SAMP>' if <VAR>chr</VAR> is a vicinity suffix character; and -<CODE>#f</CODE> otherwise. Typical vicinity suffixes are `<SAMP>/</SAMP>', -`<SAMP>:</SAMP>', and `<SAMP>\</SAMP>', -</DL> -<P> - -<A NAME="IDX65"></A> -</P> -<DL> -<DT><U>Function:</U> <B>in-vicinity</B> <I>vicinity filename</I> -<DD>Returns a filename suitable for use by <CODE>slib:load</CODE>, -<CODE>slib:load-source</CODE>, <CODE>slib:load-compiled</CODE>, -<CODE>open-input-file</CODE>, <CODE>open-output-file</CODE>, etc. The returned -filename is <VAR>filename</VAR> in <VAR>vicinity</VAR>. <CODE>in-vicinity</CODE> should -allow <VAR>filename</VAR> to override <VAR>vicinity</VAR> when <VAR>filename</VAR> is -an absolute pathname and <VAR>vicinity</VAR> is equal to the value of -<CODE>(user-vicinity)</CODE>. The behavior of <CODE>in-vicinity</CODE> when -<VAR>filename</VAR> is absolute and <VAR>vicinity</VAR> is not equal to the value -of <CODE>(user-vicinity)</CODE> is unspecified. For most systems -<CODE>in-vicinity</CODE> can be <CODE>string-append</CODE>. -</DL> -<P> - -<A NAME="IDX66"></A> -</P> -<DL> -<DT><U>Function:</U> <B>sub-vicinity</B> <I>vicinity name</I> -<DD>Returns the vicinity of <VAR>vicinity</VAR> restricted to <VAR>name</VAR>. This -is used for large systems where names of files in subsystems could -conflict. On systems with directory structure <CODE>sub-vicinity</CODE> will -return a pathname of the subdirectory <VAR>name</VAR> of -<VAR>vicinity</VAR>. -</DL> -<P> - -<A NAME="Configuration"></A> -<HR SIZE="6"> -<A NAME="SEC15"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC14"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC16"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.2 Configuration </H2> -<!--docid::SEC15::--> -<P> - -These constants and procedures describe characteristics of the Scheme -and underlying operating system. They are provided by all -implementations. -</P> -<P> - -<A NAME="IDX67"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>char-code-limit</B> -<DD>An integer 1 larger that the largest value which can be returned by -<CODE>char->integer</CODE>. -</DL> -<P> - -<A NAME="IDX68"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>most-positive-fixnum</B> -<DD>In implementations which support integers of practically unlimited size, -<VAR>most-positive-fixnum</VAR> is a large exact integer within the range of -exact integers that may result from computing the length of a list, -vector, or string. -<P> - -In implementations which do not support integers of practically -unlimited size, <VAR>most-positive-fixnum</VAR> is the largest exact integer -that may result from computing the length of a list, vector, or string. -</P> -</DL> -<P> - -<A NAME="IDX69"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>slib:tab</B> -<DD>The tab character. -</DL> -<P> - -<A NAME="IDX70"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>slib:form-feed</B> -<DD>The form-feed character. -</DL> -<P> - -<A NAME="IDX71"></A> -</P> -<DL> -<DT><U>Function:</U> <B>software-type</B> -<DD>Returns a symbol denoting the generic operating system type. For -instance, <CODE>unix</CODE>, <CODE>vms</CODE>, <CODE>macos</CODE>, <CODE>amiga</CODE>, or -<CODE>ms-dos</CODE>. -</DL> -<P> - -<A NAME="IDX72"></A> -</P> -<DL> -<DT><U>Function:</U> <B>slib:report-version</B> -<DD>Displays the versions of SLIB and the underlying Scheme implementation -and the name of the operating system. An unspecified value is returned. -<P> - -<TABLE><tr><td> </td><td class=example><pre>(slib:report-version) => slib "3a1" on scm "5b1" on unix -</pre></td></tr></table></DL> -<P> - -<A NAME="IDX73"></A> -</P> -<DL> -<DT><U>Function:</U> <B>slib:report</B> -<DD>Displays the information of <CODE>(slib:report-version)</CODE> followed by -almost all the information neccessary for submitting a problem report. -An unspecified value is returned. -<P> - -<A NAME="IDX74"></A> -<DT><U>Function:</U> <B>slib:report</B> <I>#t</I> -<DD>provides a more verbose listing. -</P> -<P> - -<A NAME="IDX75"></A> -<DT><U>Function:</U> <B>slib:report</B> <I>filename</I> -<DD>Writes the report to file `<TT>filename</TT>'. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(slib:report) -=> -slib "3a1" on scm "5b1" on unix -(implementation-vicinity) is "/usr/local/lib/scm/" -(library-vicinity) is "/usr/local/lib/slib/" -(scheme-file-suffix) is ".scm" -loaded *features* : - trace alist qp sort - common-list-functions macro values getopt - compiled -implementation *features* : - bignum complex real rational - inexact vicinity ed getenv - tmpnam abort transcript with-file - ieee-p1178 r4rs rev4-optional-procedures hash - object-hash delay eval dynamic-wind - multiarg-apply multiarg/and- logical defmacro - string-port source current-time record - rev3-procedures rev2-procedures sun-dl string-case - array dump char-ready? full-continuation - system -implementation *catalog* : - (i/o-extensions compiled "/usr/local/lib/scm/ioext.so") - ... -</pre></td></tr></table></DL> -<P> - -<A NAME="Input/Output"></A> -<HR SIZE="6"> -<A NAME="SEC16"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC15"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC17"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.3 Input/Output </H2> -<!--docid::SEC16::--> -<P> - -These procedures are provided by all implementations. -</P> -<P> - -<A NAME="IDX76"></A> -</P> -<DL> -<DT><U>Function:</U> <B>file-exists?</B> <I>filename</I> -<DD>Returns <CODE>#t</CODE> if the specified file exists. Otherwise, returns -<CODE>#f</CODE>. If the underlying implementation does not support this -feature then <CODE>#f</CODE> is always returned. -</DL> -<P> - -<A NAME="IDX77"></A> -</P> -<DL> -<DT><U>Function:</U> <B>delete-file</B> <I>filename</I> -<DD>Deletes the file specified by <VAR>filename</VAR>. If <VAR>filename</VAR> can not -be deleted, <CODE>#f</CODE> is returned. Otherwise, <CODE>#t</CODE> is -returned. -</DL> -<P> - -<A NAME="IDX78"></A> -</P> -<DL> -<DT><U>Function:</U> <B>open-file</B> <I>filename modes</I> -<DD><VAR>filename</VAR> should be a string naming a file. <CODE>open-file</CODE> -returns a port depending on the symbol <VAR>modes</VAR>: -<P> - -</P> -<DL COMPACT> -<DT>r -<DD>an input port capable of delivering characters from the file. -<DT>rb -<DD>a <EM>binary</EM> input port capable of delivering characters from the file. -<DT>w -<DD>an output port capable of writing characters to a new file by that name. -<DT>wb -<DD>a <EM>binary</EM> output port capable of writing characters to a new file -by that name. -</DL> -<P> - -If an implementation does not distinguish between binary and non-binary -files, then it must treat rb as r and wb as w. -</P> -<P> - -If the file cannot be opened, either #f is returned or an error is -signalled. For output, if a file with the given name already exists, -the effect is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX79"></A> -</P> -<DL> -<DT><U>Function:</U> <B>port?</B> <I>obj</I> -<DD>Returns <TT>#t</TT> if <VAR>obj</VAR> is an input or output port, otherwise -returns <TT>#f</TT>. -</DL> -<P> - -<A NAME="IDX80"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>close-port</B> <I>port</I> -<DD>Closes the file associated with <VAR>port</VAR>, rendering the <VAR>port</VAR> -incapable of delivering or accepting characters. -<P> - -<CODE>close-file</CODE> has no effect if the file has already been closed. -The value returned is unspecified. -</P> -</DL> -<P> - -<A NAME="IDX81"></A> -</P> -<DL> -<DT><U>Function:</U> <B>call-with-open-ports</B> <I>proc ports <small>...</small></I> -<DD><A NAME="IDX82"></A> -<DT><U>Function:</U> <B>call-with-open-ports</B> <I>ports <small>...</small> proc</I> -<DD><VAR>Proc</VAR> should be a procedure that accepts as many arguments as there -are <VAR>ports</VAR> passed to <CODE>call-with-open-ports</CODE>. -<CODE>call-with-open-ports</CODE> calls <VAR>proc</VAR> with <VAR>ports</VAR> <small>...</small>. -If <VAR>proc</VAR> returns, then the ports are closed automatically and the -value yielded by the <VAR>proc</VAR> is returned. If <VAR>proc</VAR> does not -return, then the ports will not be closed automatically unless it is -possible to prove that the ports will never again be used for a read or -write operation. -</DL> -<P> - -<A NAME="IDX83"></A> -</P> -<DL> -<DT><U>Function:</U> <B>tmpnam</B> -<DD>Returns a pathname for a file which will likely not be used by any other -process. Successive calls to <CODE>(tmpnam)</CODE> will return different -pathnames. -</DL> -<P> - -<A NAME="IDX84"></A> -</P> -<DL> -<DT><U>Function:</U> <B>current-error-port</B> -<DD>Returns the current port to which diagnostic and error output is -directed. -</DL> -<P> - -<A NAME="IDX85"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>force-output</B> -<DD><A NAME="IDX86"></A> -<DT><U>Procedure:</U> <B>force-output</B> <I>port</I> -<DD>Forces any pending output on <VAR>port</VAR> to be delivered to the output -device 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>. -</DL> -<P> - -<A NAME="IDX87"></A> -</P> -<DL> -<DT><U>Function:</U> <B>output-port-width</B> -<DD><A NAME="IDX88"></A> -<DT><U>Function:</U> <B>output-port-width</B> <I>port</I> -<DD><P> - -Returns the width of <VAR>port</VAR>, which defaults to -<CODE>(current-output-port)</CODE> if absent. If the width cannot be -determined 79 is returned. -</P> -</DL> -<P> - -<A NAME="IDX89"></A> -</P> -<DL> -<DT><U>Function:</U> <B>output-port-height</B> -<DD><A NAME="IDX90"></A> -<DT><U>Function:</U> <B>output-port-height</B> <I>port</I> -<DD><P> - -Returns the height of <VAR>port</VAR>, which defaults to -<CODE>(current-output-port)</CODE> if absent. If the height cannot be -determined 24 is returned. -</P> -</DL> -<P> - -<A NAME="System"></A> -<HR SIZE="6"> -<A NAME="SEC17"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC16"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC18"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.4 System </H2> -<!--docid::SEC17::--> -<P> - -These procedures are provided by all implementations. -</P> -<P> - -<A NAME="IDX91"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:load-source</B> <I>name</I> -<DD>Loads a file of Scheme source code from <VAR>name</VAR> with the default -filename extension used in SLIB. For instance if the filename extension -used in SLIB is `<TT>.scm</TT>' then <CODE>(slib:load-source "foo")</CODE> will -load from file `<TT>foo.scm</TT>'. -</DL> -<P> - -<A NAME="IDX92"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:load-compiled</B> <I>name</I> -<DD>On implementations which support separtely loadable compiled modules, -loads a file of compiled code from <VAR>name</VAR> with the implementation's -filename extension for compiled code appended. -</DL> -<P> - -<A NAME="IDX93"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:load</B> <I>name</I> -<DD>Loads a file of Scheme source or compiled code from <VAR>name</VAR> with the -appropriate suffixes appended. If both source and compiled code are -present with the appropriate names then the implementation will load -just one. It is up to the implementation to choose which one will be -loaded. -<P> - -If an implementation does not support compiled code then -<CODE>slib:load</CODE> will be identical to <CODE>slib:load-source</CODE>. -</P> -</DL> -<P> - -<A NAME="IDX94"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:eval</B> <I>obj</I> -<DD><CODE>eval</CODE> returns the value of <VAR>obj</VAR> evaluated in the current top -level environment. <A HREF="slib_7.html#SEC246">7.4.11 Eval</A> provides a more general evaluation -facility. -</DL> -<P> - -<A NAME="IDX95"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:eval-load</B> <I>filename eval</I> -<DD><VAR>filename</VAR> should be a string. If filename names an existing file, -the Scheme source code expressions and definitions are read from the -file and <VAR>eval</VAR> called with them sequentially. The -<CODE>slib:eval-load</CODE> procedure does not affect the values returned by -<CODE>current-input-port</CODE> and <CODE>current-output-port</CODE>. -</DL> -<P> - -<A NAME="IDX96"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:warn</B> <I>arg1 arg2 <small>...</small></I> -<DD>Outputs a warning message containing the arguments. -</DL> -<P> - -<A NAME="IDX97"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:error</B> <I>arg1 arg2 <small>...</small></I> -<DD>Outputs an error message containing the arguments, aborts evaluation of -the current form and responds in a system dependent way to the error. -Typical responses are to abort the program or to enter a read-eval-print -loop. -</DL> -<P> - -<A NAME="IDX98"></A> -</P> -<DL> -<DT><U>Procedure:</U> <B>slib:exit</B> <I>n</I> -<DD><A NAME="IDX99"></A> -<DT><U>Procedure:</U> <B>slib:exit</B> -<DD>Exits from the Scheme session returning status <VAR>n</VAR> to the system. -If <VAR>n</VAR> is omitted or <CODE>#t</CODE>, a success status is returned to the -system (if possible). If <VAR>n</VAR> is <CODE>#f</CODE> a failure is returned to -the system (if possible). If <VAR>n</VAR> is an integer, then <VAR>n</VAR> is -returned to the system (if possible). If the Scheme session cannot exit -an unspecified value is returned from <CODE>slib:exit</CODE>. -</DL> -<P> - -<A NAME="IDX100"></A> -</P> -<DL> -<DT><U>Function:</U> <B>browse-url</B> <I>url</I> -<DD>Web browsers have become so ubiquitous that programming languagues -should support a uniform interface to them. -<P> - -If a `<SAMP>netscape</SAMP>' browser is running, <CODE>browse-url</CODE> causes the -browser to display the page specified by string <VAR>url</VAR> and returns -#t. -</P> -<P> - -If the browser is not running, <CODE>browse-url</CODE> starts a browser -displaying the argument <VAR>url</VAR>. If the browser starts as a -background job, <CODE>browse-url</CODE> returns #t immediately; if the -browser starts as a foreground job, then <CODE>browse-url</CODE> returns #t -when the browser exits; otherwise it returns #f. -</P> -</DL> -<P> - -<A NAME="Miscellany"></A> -<HR SIZE="6"> -<A NAME="SEC18"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC17"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC19"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.5 Miscellany </H2> -<!--docid::SEC18::--> -<P> - -These procedures are provided by all implementations. -</P> -<P> - -<A NAME="IDX101"></A> -</P> -<DL> -<DT><U>Function:</U> <B>identity</B> <I>x</I> -<DD><VAR>identity</VAR> returns its argument. -<P> - -Example: -<TABLE><tr><td> </td><td class=example><pre>(identity 3) - => 3 -(identity '(foo bar)) - => (foo bar) -(map identity <VAR>lst</VAR>) - == (copy-list <VAR>lst</VAR>) -</pre></td></tr></table></DL> -<P> - -<HR SIZE="6"> -<A NAME="SEC19"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC18"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC20"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.5.1 Mutual Exclusion </H3> -<!--docid::SEC19::--> -<P> - -An <EM>exchanger</EM> is a procedure of one argument regulating mutually -<A NAME="IDX102"></A> -exclusive access to a resource. When a exchanger is called, its current -content is returned, while being replaced by its argument in an atomic -operation. -</P> -<P> - -<A NAME="IDX103"></A> -</P> -<DL> -<DT><U>Function:</U> <B>make-exchanger</B> <I>obj</I> -<DD><P> - -Returns a new exchanger with the argument <VAR>obj</VAR> as its initial -content. -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define queue (make-exchanger (list a))) -</pre></td></tr></table><P> - -A queue implemented as an exchanger holding a list can be protected from -reentrant execution thus: -</P> -<P> - -<TABLE><tr><td> </td><td class=example><pre>(define (pop queue) - (let ((lst #f)) - (dynamic-wind - (lambda () (set! lst (queue #f))) - (lambda () (and lst (not (null? lst)) - (let ((ret (car lst))) - (set! lst (cdr lst)) - ret))) - (lambda () (and lst (queue lst)))))) - -(pop queue) => a - -(pop queue) => #f -</pre></td></tr></table></DL> -<P> - -<HR SIZE="6"> -<A NAME="SEC20"></A> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC19"> < </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> > </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> Up </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> 2.5.2 Legacy </H3> -<!--docid::SEC20::--> -<P> - -The following procedures were present in Scheme until R4RS -(see section `Language changes' in <CITE>Revised(4) Scheme</CITE>). -They are provided by all SLIB implementations. -</P> -<P> - -<A NAME="IDX104"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>t</B> -<DD>Derfined as <CODE>#t</CODE>. -</DL> -<P> - -<A NAME="IDX105"></A> -</P> -<DL> -<DT><U>Constant:</U> <B>nil</B> -<DD>Defined as <CODE>#f</CODE>. -</DL> -<P> - -<A NAME="IDX106"></A> -</P> -<DL> -<DT><U>Function:</U> <B>last-pair</B> <I>l</I> -<DD>Returns the last pair in the list <VAR>l</VAR>. Example: -<TABLE><tr><td> </td><td class=example><pre>(last-pair (cons 1 2)) - => (1 . 2) -(last-pair '(1 2)) - => (2) - == (cons 2 '()) -</pre></td></tr></table></DL> -<P> - -<A NAME="Scheme Syntax Extension Packages"></A> -<HR SIZE="6"> -<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0> -<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> << </A>]</TD> -<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_3.html#SEC21"> >> </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> |