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+<TITLE>SLIB: The Library System</TITLE>
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+</TR></TABLE>
+<A NAME="The Library System"></A>
+<H1> 1. The Library System </H1>
+<!--docid::SEC1::-->
+<P>
+
+<TABLE BORDER="0" CELLSPACING="0">
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC2">1.1 Feature</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP">SLIB names.</TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC3">1.2 Require</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC4">1.3 Library Catalogs</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC5">1.4 Catalog Creation</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC6">1.5 Catalog Vicinities</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC7">1.6 Compiling Scheme</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+</TABLE>
+<P>
+
+<A NAME="Feature"></A>
+<HR SIZE="6">
+<A NAME="SEC2"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt; </A>]</TD>
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+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.1 Feature </H2>
+<!--docid::SEC2::-->
+<P>
+
+<A NAME="IDX1"></A>
+SLIB denotes <EM>features</EM> by symbols. SLIB maintains a list of
+features supported by a Scheme <EM>session</EM>. The set of features
+<A NAME="IDX2"></A>
+provided by a session may change during that session. Some features
+are properties of the Scheme implementation being used. The following
+<A NAME="IDX3"></A>
+<EM>intrinsic feature</EM>s detail what sort of numbers are available
+from an implementation:
+</P>
+<P>
+
+<UL>
+<LI>
+'inexact
+<LI>
+'rational
+<LI>
+'real
+<LI>
+'complex
+<LI>
+'bignum
+</UL>
+<P>
+
+SLIB initialization (in `<TT>require.scm</TT>') tests and <EM>provide</EM>s
+any of these numeric features which are appropriate.
+</P>
+<P>
+
+Other features correspond to the presence of packages of Scheme
+procedures or syntax (macros).
+</P>
+<P>
+
+<A NAME="IDX4"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>provided?</B> <I>feature</I>
+<DD>Returns <CODE>#t</CODE> if <VAR>feature</VAR> is present in the current Scheme
+session; otherwise <CODE>#f</CODE>. More specifically, <CODE>provided?</CODE>
+returns <CODE>#t</CODE> if the symbol <VAR>feature</VAR> is the
+<CODE>software-type</CODE> or if <VAR>feature</VAR> has been provided by a module
+already loaded; and <CODE>#f</CODE> otherwise.
+<P>
+
+In some implementations <CODE>provided?</CODE> tests whether a module has
+been <CODE>require</CODE>d by any module or in any thread; other
+implementations will have <CODE>provided?</CODE> reflect only the modules
+<CODE>require</CODE>d by that particular session or thread.
+</P>
+<P>
+
+To work portably in both scenarios, use <CODE>provided?</CODE> only to test
+whether intrinsic properties (like those above) are present.
+</P>
+<P>
+
+The <VAR>feature</VAR> argument can also be an expression calling
+<CODE>and</CODE>, <CODE>or</CODE>, and <CODE>not</CODE> of features. The boolean result
+of the logical question asked by <VAR>feature</VAR> is returned.
+</P>
+</DL>
+<P>
+
+The generalization of <CODE>provided?</CODE> for arbitrary features and catalog
+is <CODE>feature-eval</CODE>:
+</P>
+<P>
+
+<A NAME="IDX5"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>feature-eval</B> <I>expression provided?</I>
+<DD>Evaluates <CODE>and</CODE>, <CODE>or</CODE>, and <CODE>not</CODE> forms in
+<VAR>expression</VAR>, using the values returned by calling <VAR>provided?</VAR>
+on the leaf symbols. <CODE>feature-eval</CODE> returns the boolean result
+of the logical combinations.
+</DL>
+<P>
+
+<A NAME="IDX6"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>provide</B> <I>feature</I>
+<DD>Informs SLIB that <VAR>feature</VAR> is supported in this session.
+</DL>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(provided? 'foo) => #f
+(provide 'foo)
+(provided? 'foo) => #t
+</pre></td></tr></table><P>
+
+<A NAME="Require"></A>
+<HR SIZE="6">
+<A NAME="SEC3"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC2"> &lt; </A>]</TD>
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+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.2 Require </H2>
+<!--docid::SEC3::-->
+<P>
+
+<A NAME="IDX7"></A>
+SLIB creates and maintains a <EM>catalog</EM> mapping features to locations
+of files introducing procedures and syntax denoted by those features.
+</P>
+<P>
+
+<A NAME="IDX8"></A>
+</P>
+<DL>
+<DT><U>Variable:</U> <B>*catalog*</B>
+<DD>Is an association list of features (symbols) and pathnames which will
+supply those features. The pathname can be either a string or a pair.
+If pathname is a pair then the first element should be a macro feature
+symbol, <CODE>source</CODE>, <CODE>compiled</CODE>, or one of the other cases
+described in <A HREF="slib_1.html#SEC4">1.3 Library Catalogs</A>. The cdr of the pathname should
+be either a string or a list.
+</DL>
+<P>
+
+At the beginning of each section of this manual, there is a line like
+<CODE>(require '<VAR>feature</VAR>)</CODE>.
+<A NAME="IDX9"></A>
+The Scheme files comprising SLIB are cataloged so that these feature
+names map to the corresponding files.
+</P>
+<P>
+
+SLIB provides a form, <CODE>require</CODE>, which loads the files providing
+the requested feature.
+</P>
+<P>
+
+<A NAME="IDX10"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>require</B> <I>feature</I>
+<DD><UL>
+<LI>
+If <CODE>(provided? <VAR>feature</VAR>)</CODE> is true,
+then <CODE>require</CODE> just returns.
+<LI>
+Otherwise, if <VAR>feature</VAR> is found in the catalog, then the
+corresponding files will be loaded and <CODE>(provided?
+<VAR>feature</VAR>)</CODE> will henceforth return <CODE>#t</CODE>. That <VAR>feature</VAR>
+is thereafter <CODE>provided</CODE>.
+<LI>
+Otherwise (<VAR>feature</VAR> not found in the catalog), an error is
+signaled.
+</UL>
+</DL>
+<P>
+
+There is a related form <CODE>require-if</CODE>, used primarily for enabling
+compilers to statically include modules which would be dynamically
+loaded by interpreters.
+</P>
+<P>
+
+<A NAME="IDX11"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>require-if</B> <I>condition feature</I>
+<DD><P>
+
+Requires <VAR>feature</VAR> if <VAR>condition</VAR> is true.
+</P>
+</DL>
+<P>
+
+The <CODE>random</CODE> module uses <CODE>require-if</CODE> to flag
+<CODE>object-&gt;string</CODE> as a (dynamic) required module.
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(require 'byte)
+(require 'logical)
+(require-if 'compiling 'object-&gt;string)
+</pre></td></tr></table><P>
+
+The <CODE>batch</CODE> module uses <CODE>require-if</CODE> to flag
+<CODE>posix-time</CODE> as a module to load if the implementation supports
+large precision exact integers.
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(require-if '(and bignum compiling) 'posix-time)
+</pre></td></tr></table><P>
+
+The <CODE>commutative-ring</CODE> module uses <CODE>require-if</CODE> to ensure
+that it has an exponentiation routine, regardless of whether the
+implementation supports inexact numbers:
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(require-if '(not inexact) 'logical) ;for integer-expt
+(define number^ (if (provided? 'inexact) expt integer-expt))
+</pre></td></tr></table><P>
+
+The catalog can also be queried using <CODE>slib:in-catalog?</CODE>.
+</P>
+<P>
+
+<A NAME="IDX12"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>slib:in-catalog?</B> <I>feature</I>
+<DD>Returns a <CODE>CDR</CODE> of the catalog entry if one was found for the
+symbol <VAR>feature</VAR> in the alist <CODE>*catalog*</CODE> (and transitively
+through any symbol aliases encountered). Otherwise, returns
+<CODE>#f</CODE>. The format of catalog entries is explained in <A HREF="slib_1.html#SEC4">1.3 Library Catalogs</A>.
+</DL>
+<P>
+
+<A NAME="Library Catalogs"></A>
+<HR SIZE="6">
+<A NAME="SEC4"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC3"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC5"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.3 Library Catalogs </H2>
+<!--docid::SEC4::-->
+<P>
+
+Catalog files consist of one or more <EM>association list</EM>s.
+<A NAME="IDX13"></A>
+In the circumstance where a feature symbol appears in more than one
+list, the latter list's association is retrieved. Here are the
+supported formats for elements of catalog lists:
+</P>
+<P>
+
+</P>
+<DL COMPACT>
+<DT><CODE>(<VAR>feature</VAR> . <I>&lt;symbol&gt;</I>)</CODE>
+<DD>Redirects to the feature named <I>&lt;symbol&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> . &quot;<I>&lt;path&gt;</I>&quot;)</CODE>
+<DD>Loads file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> source &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX14"></A>
+<CODE>slib:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> compiled &quot;<I>&lt;path&gt;&quot;</I> <small>...</small>)</CODE>
+<DD><A NAME="IDX15"></A>
+<CODE>slib:load-compiled</CODE>s the files <I>&lt;path&gt;</I> <small>...</small>.
+<DT><CODE>(<VAR>feature</VAR> aggregate <I>&lt;symbol&gt;</I> <small>...</small>)</CODE>
+<DD><A NAME="IDX16"></A>
+<CODE>slib:require</CODE>s the features <I>&lt;symbol&gt;</I> <small>...</small>.
+</DL>
+<P>
+
+The various macro styles first <CODE>require</CODE> the named macro package,
+then just load <I>&lt;path&gt;</I> or load-and-macro-expand <I>&lt;path&gt;</I> as
+appropriate for the implementation.
+</P>
+<P>
+
+</P>
+<DL COMPACT>
+<DT><CODE>(<VAR>feature</VAR> defmacro &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX17"></A>
+<CODE>defmacro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> macro-by-example &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX18"></A>
+<CODE>defmacro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+</DL>
+<P>
+
+</P>
+<DL COMPACT>
+<DT><CODE>(<VAR>feature</VAR> macro &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX19"></A>
+<CODE>macro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> macros-that-work &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX20"></A>
+<CODE>macro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> syntax-case &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX21"></A>
+<CODE>macro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+<DT><CODE>(<VAR>feature</VAR> syntactic-closures &quot;<I>&lt;path&gt;&quot;</I>)</CODE>
+<DD><A NAME="IDX22"></A>
+<CODE>macro:load</CODE>s the Scheme source file <I>&lt;path&gt;</I>.
+</DL>
+<P>
+
+<A NAME="Catalog Creation"></A>
+<HR SIZE="6">
+<A NAME="SEC5"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC4"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC6"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.4 Catalog Creation </H2>
+<!--docid::SEC5::-->
+<P>
+
+At the start of an interactive session no catalog is present, but is
+created with the first catalog inquiry (such as <CODE>(require
+'random)</CODE>). Several sources of catalog information are combined to
+produce the catalog:
+</P>
+<P>
+
+<UL>
+<LI>
+standard SLIB packages.
+<LI>
+additional packages of interest to this site.
+<LI>
+packages specifically for the variety of Scheme which this
+session is running.
+<LI>
+packages this user wants to always have available. This catalog is the
+file `<TT>homecat</TT>' in the user's <EM>HOME</EM> directory.
+<A NAME="IDX23"></A>
+<LI>
+packages germane to working in this (current working) directory. This
+catalog is the file `<TT>usercat</TT>' in the directory to which it applies.
+One would typically <CODE>cd</CODE> to this directory before starting the
+Scheme session.
+<LI>
+packages which are part of an application program.
+</UL>
+<P>
+
+SLIB combines the catalog information which doesn't vary per user into
+the file `<TT>slibcat</TT>' in the implementation-vicinity. Therefore
+`<TT>slibcat</TT>' needs change only when new software is installed or
+compiled. Because the actual pathnames of files can differ from
+installation to installation, SLIB builds a separate catalog for each
+implementation it is used with.
+</P>
+<P>
+
+The definition of <CODE>*SLIB-VERSION*</CODE> in SLIB file
+`<TT>require.scm</TT>' is checked against the catalog association of
+<CODE>*SLIB-VERSION*</CODE> to ascertain when versions have changed. It is
+a reasonable practice to change the definition of
+<CODE>*SLIB-VERSION*</CODE> whenever the library is changed. If multiple
+implementations of Scheme use SLIB, remember that recompiling one
+`<TT>slibcat</TT>' will update only that implementation's catalog.
+</P>
+<P>
+
+The compilation scripts of Scheme implementations which work with SLIB
+can automatically trigger catalog compilation by deleting
+`<TT>slibcat</TT>' or by invoking <CODE>require</CODE> of a special feature:
+</P>
+<P>
+
+<A NAME="IDX24"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>require</B> <I>'new-catalog</I>
+<DD><A NAME="IDX25"></A>
+This will load `<TT>mklibcat</TT>', which compiles and writes a new
+`<TT>slibcat</TT>'.
+</DL>
+<P>
+
+Another special feature of <CODE>require</CODE> erases SLIB's catalog,
+forcing it to be reloaded the next time the catalog is queried.
+</P>
+<P>
+
+<A NAME="IDX26"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>require</B> <I>#f</I>
+<DD>Removes SLIB's catalog information. This should be done before saving
+an executable image so that, when restored, its catalog will be loaded
+afresh.
+</DL>
+<P>
+
+<A NAME="Catalog Vicinities"></A>
+<HR SIZE="6">
+<A NAME="SEC6"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC5"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.5 Catalog Vicinities </H2>
+<!--docid::SEC6::-->
+<P>
+
+Each file in the table below is descibed in terms of its
+file-system independent <EM>vicinity</EM> (see section <A HREF="slib_2.html#SEC14">2.1 Vicinity</A>). The entries
+of a catalog in the table override those of catalogs above it in the
+table.
+</P>
+<P>
+
+</P>
+<DL COMPACT>
+
+<DT><CODE>implementation-vicinity</CODE> `<TT>slibcat</TT>'
+<DD><A NAME="IDX27"></A>
+This file contains the associations for the packages comprising SLIB,
+the `<TT>implcat</TT>' and the `<TT>sitecat</TT>'s. The associations in the
+other catalogs override those of the standard catalog.
+<P>
+
+</P>
+<DT><CODE>library-vicinity</CODE> `<TT>mklibcat.scm</TT>'
+<DD><A NAME="IDX28"></A>
+creates `<TT>slibcat</TT>'.
+<P>
+
+</P>
+<DT><CODE>library-vicinity</CODE> `<TT>sitecat</TT>'
+<DD><A NAME="IDX29"></A>
+This file contains the associations specific to an SLIB installation.
+<P>
+
+</P>
+<DT><CODE>implementation-vicinity</CODE> `<TT>implcat</TT>'
+<DD><A NAME="IDX30"></A>
+This file contains the associations specific to an implementation of
+Scheme. Different implementations of Scheme should have different
+<CODE>implementation-vicinity</CODE>.
+<P>
+
+</P>
+<DT><CODE>implementation-vicinity</CODE> `<TT>mkimpcat.scm</TT>'
+<DD><A NAME="IDX31"></A>
+if present, creates `<TT>implcat</TT>'.
+<P>
+
+</P>
+<DT><CODE>implementation-vicinity</CODE> `<TT>sitecat</TT>'
+<DD><A NAME="IDX32"></A>
+This file contains the associations specific to a Scheme implementation
+installation.
+<P>
+
+</P>
+<DT><CODE>home-vicinity</CODE> `<TT>homecat</TT>'
+<DD><A NAME="IDX33"></A>
+This file contains the associations specific to an SLIB user.
+<P>
+
+</P>
+<DT><CODE>user-vicinity</CODE> `<TT>usercat</TT>'
+<DD><A NAME="IDX34"></A>
+This file contains associations affecting only those sessions whose
+<EM>working directory</EM> is <CODE>user-vicinity</CODE>.
+<P>
+
+</DL>
+<P>
+
+Here is an example of a `<TT>usercat</TT>' catalog. A program in this
+directory can invoke the `<SAMP>run</SAMP>' feature with <CODE>(require 'run)</CODE>.
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>;;; &quot;usercat&quot;: SLIB catalog additions for SIMSYNCH. -*-scheme-*-
+(
+ (simsynch . &quot;../synch/simsynch.scm&quot;)
+ (run . &quot;../synch/run.scm&quot;)
+ (schlep . &quot;schlep.scm&quot;)
+)
+</pre></td></tr></table><P>
+
+Copying `<TT>usercat</TT>' to many directories is inconvenient.
+Application programs which aren't always run in specially prepared
+directories can nonetheless register their features during
+initialization.
+</P>
+<P>
+
+<A NAME="IDX35"></A>
+</P>
+<DL>
+<DT><U>Procedure:</U> <B>catalog:read</B> <I>vicinity catalog</I>
+<DD>Reads file named by string <VAR>catalog</VAR> in <VAR>vicinity</VAR>, resolving
+all paths relative to <VAR>vicinity</VAR>, and adds those feature
+associations to <VAR>*catalog*</VAR>.
+<P>
+
+<CODE>catalog:read</CODE> would typically be used by an application program
+having dynamically loadable modules. For instance, to register
+factoring and other modules in <VAR>*catalog*</VAR>, JACAL does:
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(catalog:read (program-vicinity) &quot;jacalcat&quot;)
+</pre></td></tr></table><P>
+
+</P>
+</DL>
+<P>
+
+For an application program there are three appropriate venues for
+registering its catalog associations:
+</P>
+<P>
+
+<UL>
+<LI>
+in a `<TT>usercat</TT>' file in the directory where the program runs; or
+<LI>
+in an `<TT>implcat</TT>' file in the <CODE>implementation-vicinity</CODE>; or
+<LI>
+in an application program directory; loaded by calling
+<CODE>catalog:read</CODE>.
+</UL>
+<P>
+
+<A NAME="Compiling Scheme"></A>
+<HR SIZE="6">
+<A NAME="SEC7"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC6"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC8"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6 Compiling Scheme </H2>
+<!--docid::SEC7::-->
+<P>
+
+To use Scheme compilers effectively with SLIB the compiler needs to
+know which SLIB modules are to be compiled and which symbols are
+exported from those modules.
+</P>
+<P>
+
+The procedures in this section automate the extraction of this
+information from SLIB modules. They are guaranteed to work on SLIB
+modules; to use them on other sources, those sources should follow
+SLIB conventions.
+</P>
+<P>
+
+<TABLE BORDER="0" CELLSPACING="0">
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC8">1.6.1 Module Conventions</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC9">1.6.2 Module Manifests</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC10">1.6.3 Module Semantics</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC11">1.6.4 Top-level Variable References</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="slib_1.html#SEC12">1.6.5 Module Analysis</A></TD><TD>&nbsp;&nbsp;</TD><TD ALIGN="left" VALIGN="TOP"></TD></TR>
+</TABLE>
+<P>
+
+<A NAME="Module Conventions"></A>
+<HR SIZE="6">
+<A NAME="SEC8"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC9"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6.1 Module Conventions </H3>
+<!--docid::SEC8::-->
+<P>
+
+<UL>
+<LI>
+All the top-level <CODE>require</CODE> commands have one quoted argument and
+are positioned before other Scheme definitions and expressions in the
+file.
+<LI>
+Any conditionally <CODE>require</CODE>d SLIB modules
+<A NAME="DOCF1" HREF="slib_fot.html#FOOT1">(1)</A>
+also appear at the beginning of their files conditioned on the feature
+<A NAME="IDX36"></A>
+<CODE>compiling</CODE> using <CODE>require-if</CODE>
+(see section <A HREF="slib_1.html#SEC3">require-if</A>).
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(require 'logical)
+(require 'multiarg/and-)
+(require-if 'compiling 'sort)
+(require-if 'compiling 'ciexyz)
+</pre></td></tr></table><P>
+
+</P>
+<LI>
+Schmooz-style comments preceding a definition, identify that
+definition as an exported identifier (see section <A HREF="slib_4.html#SEC87">4.14 Schmooz</A>). For
+non-schmooz files, putting `<SAMP>;@</SAMP>' at the beginning of the line
+immediately preceding the definition (<CODE>define</CODE>,
+<CODE>define-syntax</CODE>, or <CODE>defmacro</CODE>) suffices.
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>;@
+(define (make-vicinity &lt;pathname&gt;) &lt;pathname&gt;)
+</pre></td></tr></table><P>
+
+</P>
+<LI>
+Syntax (macro) definitions are grouped at the end of a module file.
+<P>
+
+</P>
+<LI>
+Modules defining macros do not invoke those macros. SLIB macro
+implementations are exempt from this rule.
+<P>
+
+An example of how to expand macro invocations is:
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(require 'macros-that-work)
+(require 'yasos)
+(require 'pprint-file)
+(pprint-filter-file &quot;collect.scm&quot; macwork:expand)
+</pre></td></tr></table><P>
+
+</UL>
+<P>
+
+<A NAME="Module Manifests"></A>
+<HR SIZE="6">
+<A NAME="SEC9"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC8"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC10"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6.2 Module Manifests </H3>
+<!--docid::SEC9::-->
+<P>
+
+<CODE>(require 'manifest)</CODE>
+<A NAME="IDX37"></A>
+</P>
+<P>
+
+In some of these examples, <VAR>slib:catalog</VAR> is the SLIB part of
+the catalog; it is free of compiled and implementation-specific
+entries. It would be defined by:
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(define slib:catalog (cdr (member (assq 'null *catalog*) *catalog*)))
+</pre></td></tr></table><P>
+
+<A NAME="IDX38"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>file-&gt;requires</B> <I>file provided? catalog</I>
+<DD><P>
+
+Returns a list of the features <CODE>require</CODE>d by <VAR>file</VAR> assuming the
+predicate <VAR>provided?</VAR> and association-list <VAR>catalog</VAR>.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(define (provided+? . features)
+ (lambda (feature)
+ (or (memq feature features) (provided? feature))))
+
+(file-&gt;requires &quot;obj2str.scm&quot; (provided+? 'compiling) '())
+ => (string-port generic-write)
+
+(file-&gt;requires &quot;obj2str.scm&quot; provided? '())
+ => (string-port)
+</pre></td></tr></table><P>
+
+<A NAME="IDX39"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>feature-&gt;requires</B> <I>feature provided? catalog</I>
+<DD><P>
+
+Returns a list of the features <CODE>require</CODE>d by <VAR>feature</VAR> assuming the
+predicate <VAR>provided?</VAR> and association-list <VAR>catalog</VAR>.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(feature-&gt;requires 'batch (provided+? 'compiling) *catalog*)
+ => (tree line-i/o databases parameters string-port
+ pretty-print common-list-functions posix-time)
+
+(feature-&gt;requires 'batch provided? *catalog*)
+ => (tree line-i/o databases parameters string-port
+ pretty-print common-list-functions)
+
+(feature-&gt;requires 'batch provided? '((batch . &quot;batch&quot;)))
+ => (tree line-i/o databases parameters string-port
+ pretty-print common-list-functions)
+</pre></td></tr></table><P>
+
+<A NAME="IDX40"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>file-&gt;loads</B> <I>file</I>
+<DD><P>
+
+Returns a list of strings naming existing files loaded (load
+slib:load slib:load-source macro:load defmacro:load syncase:load
+synclo:load macwork:load) by <VAR>file</VAR> or any of the files it loads.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(file-&gt;loads (in-vicinity (library-vicinity) &quot;scainit.scm&quot;))
+ => (&quot;/usr/local/lib/slib/scaexpp.scm&quot;
+ &quot;/usr/local/lib/slib/scaglob.scm&quot;
+ &quot;/usr/local/lib/slib/scaoutp.scm&quot;)
+</pre></td></tr></table><P>
+
+<A NAME="IDX41"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>load-&gt;path</B> <I>exp</I>
+<DD><P>
+
+Given a <CODE>(load '&lt;expr&gt;)</CODE>, where &lt;expr&gt; is a string or vicinity
+stuff), <CODE>(load-&gt;path &lt;expr&gt;)</CODE> figures a path to the file.
+<CODE>load-&gt;path</CODE> returns that path if it names an existing file; otherwise #f.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(load-&gt;path '(in-vicinity (library-vicinity) &quot;mklibcat&quot;))
+ => &quot;/usr/local/lib/slib/mklibcat.scm&quot;
+</pre></td></tr></table><P>
+
+<A NAME="IDX42"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>file-&gt;definitions</B> <I>file</I>
+<DD><P>
+
+Returns a list of the identifier symbols defined by SLIB (or
+SLIB-style) file <VAR>file</VAR>.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(file-&gt;definitions &quot;random.scm&quot;)
+ => (*random-state* make-random-state
+ seed-&gt;random-state copy-random-state random
+ random:chunk)
+</pre></td></tr></table><P>
+
+<A NAME="IDX43"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>file-&gt;exports</B> <I>file</I>
+<DD><P>
+
+Returns a list of the identifier symbols exported (advertised) by
+SLIB (or SLIB-style) file <VAR>file</VAR>.
+</P>
+</DL>
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(file-&gt;exports &quot;random.scm&quot;)
+ => (make-random-state seed-&gt;random-state
+ copy-random-state random)
+
+(file-&gt;exports &quot;randinex.scm&quot;)
+ => (random:solid-sphere! random:hollow-sphere!
+ random:normal-vector! random:normal
+ random:exp random:uniform)
+</pre></td></tr></table><P>
+
+<A NAME="IDX44"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>feature-&gt;export-alist</B> <I>feature catalog</I>
+<DD><P>
+
+Returns a list of lists; each sublist holding the name of the file
+implementing <VAR>feature</VAR>, and the identifier symbols exported (advertised) by
+SLIB (or SLIB-style) feature <VAR>feature</VAR>, in <VAR>catalog</VAR>.
+</P>
+</DL>
+<P>
+
+<A NAME="IDX45"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>feature-&gt;exports</B> <I>feature catalog</I>
+<DD><P>
+
+Returns a list of all exports of <VAR>feature</VAR>.
+</P>
+</DL>
+In the case of <CODE>aggregate</CODE> features, more than one file may
+have export lists to report:
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(feature-&gt;export-alist 'r5rs slib:catalog))
+ => ((&quot;/usr/local/lib/slib/values.scm&quot;
+ call-with-values values)
+ (&quot;/usr/local/lib/slib/mbe.scm&quot;
+ define-syntax macro:expand
+ macro:load macro:eval)
+ (&quot;/usr/local/lib/slib/eval.scm&quot;
+ eval scheme-report-environment
+ null-environment interaction-environment))
+
+(feature-&gt;export-alist 'stdio *catalog*)
+ => ((&quot;/usr/local/lib/slib/scanf.scm&quot;
+ fscanf sscanf scanf scanf-read-list)
+ (&quot;/usr/local/lib/slib/printf.scm&quot;
+ sprintf printf fprintf)
+ (&quot;/usr/local/lib/slib/stdio.scm&quot;
+ stderr stdout stdin))
+
+(feature-&gt;exports 'stdio slib:catalog)
+ => (fscanf sscanf scanf scanf-read-list
+ sprintf printf fprintf stderr stdout stdin)
+</pre></td></tr></table><P>
+
+<A NAME="Module Semantics"></A>
+<HR SIZE="6">
+<A NAME="SEC10"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC9"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC11"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6.3 Module Semantics </H3>
+<!--docid::SEC10::-->
+<P>
+
+For the purpose of compiling Scheme code, each top-level
+<CODE>require</CODE> makes the identifiers exported by its feature's module
+<CODE>defined</CODE> (or defmacroed or defined-syntaxed) within the file
+(being compiled) headed with those requires.
+</P>
+<P>
+
+Top-level occurrences of <CODE>require-if</CODE> make defined the exports
+from the module named by the second argument <EM>if</EM> the
+<VAR>feature-expression</VAR> first argument is true in the target
+environment. The target feature <CODE>compiling</CODE> should be provided
+during this phase of compilation.
+</P>
+<P>
+
+Non-top-level SLIB occurences of <CODE>require</CODE> and <CODE>require-if</CODE>
+of quoted features can be ignored by compilers. The SLIB modules will
+all have top-level constructs for those features.
+</P>
+<P>
+
+<A NAME="IDX46"></A>
+Note that aggregate catalog entries import more than one module.
+Implementations of <CODE>require</CODE> may or may <EM>not</EM> be transitive;
+code which uses module exports without requiring the providing module
+is in error.
+</P>
+<P>
+
+In the SLIB modules <CODE>modular</CODE>, <CODE>batch</CODE>, <CODE>hash</CODE>,
+<CODE>common-lisp-time</CODE>, <CODE>commutative-ring</CODE>, <CODE>charplot</CODE>,
+<CODE>logical</CODE>, <CODE>common-list-functions</CODE>, <CODE>coerce</CODE> and
+<CODE>break</CODE> there is code conditional on features being
+<CODE>provided?</CODE>. Most are testing for the presence of features which
+are intrinsic to implementations (inexacts, bignums, ...).
+</P>
+<P>
+
+In all cases these <CODE>provided?</CODE> tests can be evaluated at
+compile-time using <CODE>feature-eval</CODE>
+(see section <A HREF="slib_1.html#SEC2">feature-eval</A>). The simplest way to compile these
+constructs may be to treat <CODE>provided?</CODE> as a macro.
+</P>
+<P>
+
+<A NAME="Top-level Variable References"></A>
+<HR SIZE="6">
+<A NAME="SEC11"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC10"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC12"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6.4 Top-level Variable References </H3>
+<!--docid::SEC11::-->
+<P>
+
+<CODE>(require 'top-refs)</CODE>
+<A NAME="IDX47"></A>
+<A NAME="IDX48"></A>
+<A NAME="IDX49"></A>
+</P>
+<P>
+
+These procedures complement those in <A HREF="slib_1.html#SEC9">1.6.2 Module Manifests</A> by
+finding the top-level variable references in Scheme source code.
+They work by traversing expressions and definitions, keeping track
+of bindings encountered. It is certainly possible to foil these
+functions, but they return useful information about SLIB source
+code.
+</P>
+<P>
+
+<A NAME="IDX50"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>top-refs</B> <I>obj</I>
+<DD><P>
+
+Returns a list of the top-level variables referenced by the Scheme
+expression <VAR>obj</VAR>.
+</P>
+</DL>
+<P>
+
+<A NAME="IDX51"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>top-refs&lt;-file</B> <I>filename</I>
+<DD><P>
+
+<VAR>filename</VAR> should be a string naming an existing file containing Scheme
+source code. <CODE>top-refs&lt;-file</CODE> returns a list of the top-level variable references
+made by expressions in the file named by <VAR>filename</VAR>.
+</P>
+<P>
+
+Code in modules which <VAR>filename</VAR> <CODE>require</CODE>s is not traversed. Code in
+files loaded from top-level <EM>is</EM> traversed if the expression
+argument to <CODE>load</CODE>, <CODE>slib:load</CODE>, <CODE>slib:load-source</CODE>,
+<CODE>macro:load</CODE>, <CODE>defmacro:load</CODE>, <CODE>synclo:load</CODE>,
+<CODE>syncase:load</CODE>, or <CODE>macwork:load</CODE> is a literal string
+constant or composed of combinations of vicinity functions and
+string literal constants; and the resulting file exists (possibly
+with &quot;.scm&quot; appended).
+</P>
+</DL>
+The following function parses an <EM>Info</EM> Index.
+<A NAME="IDX52"></A>
+<A NAME="DOCF2" HREF="slib_fot.html#FOOT2">(2)</A>
+<P>
+
+<A NAME="IDX53"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>exports&lt;-info-index</B> <I>file n <small>...</small></I>
+<DD><P>
+
+<VAR>n</VAR> <small>...</small> must be an increasing series of positive integers.
+<CODE>exports&lt;-info-index</CODE> returns a list of all the identifiers appearing in the <VAR>n</VAR>th
+<small>...</small> (info) indexes of <VAR>file</VAR>. The identifiers have the case that
+the implementation's <CODE>read</CODE> uses for symbols. Identifiers
+containing spaces (eg. <CODE>close-base on base-table</CODE>) are
+<EM>not</EM> included.
+</P>
+<P>
+
+Each info index is headed by a `<SAMP>* Menu:</SAMP>' line. To list the
+symbols in the first and third info indexes do:
+</P>
+<P>
+
+<TABLE><tr><td>&nbsp;</td><td class=example><pre>(exports&lt;-info-index &quot;slib.info&quot; 1 3)
+</pre></td></tr></table></DL>
+<P>
+
+<A NAME="Module Analysis"></A>
+<HR SIZE="6">
+<A NAME="SEC12"></A>
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC11"> &lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC7"> Up </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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> 1.6.5 Module Analysis </H3>
+<!--docid::SEC12::-->
+<P>
+
+<CODE>(require 'vet)</CODE>
+<A NAME="IDX54"></A>
+</P>
+<P>
+
+<A NAME="IDX55"></A>
+</P>
+<DL>
+<DT><U>Function:</U> <B>vet-slib</B>
+<DD><P>
+
+Using the procedures in the <CODE>top-refs</CODE> and <CODE>manifest</CODE>
+modules, <CODE>vet-slib</CODE> analyzes each SLIB module, reporting about any
+procedure or macro defined whether it is:
+</P>
+<P>
+
+</P>
+<DL COMPACT>
+
+<DT>orphaned
+<DD>defined, not called, not exported;
+<DT>missing
+<DD>called, not defined, and not exported by its <CODE>require</CODE>d modules;
+<DT>undocumented-export
+<DD>Exported by module, but no index entry in `<TT>slib.info</TT>';
+<P>
+
+</DL>
+<P>
+
+And for the library as a whole:
+</P>
+<P>
+
+</P>
+<DL COMPACT>
+
+<DT>documented-unexport
+<DD>Index entry in `<TT>slib.info</TT>', but no module exports it.
+<P>
+
+</DL>
+<P>
+
+This straightforward analysis caught three full days worth of
+never-executed branches, transitive require assumptions, spelling
+errors, undocumented procedures, missing procedures, and cyclic
+dependencies in SLIB.
+</P>
+</DL>
+<P>
+
+<A NAME="Universal SLIB Procedures"></A>
+<HR SIZE="6">
+<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
+<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_1.html#SEC1"> &lt;&lt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="slib_2.html#SEC13"> &gt;&gt; </A>]</TD>
+<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <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>