[Document SOURCE pragma; clarify TH behavior for mutually-recurive modules (Trac #1012)
simonpj@microsoft.com**20080104121939] {
hunk ./docs/users_guide/glasgow_exts.xml 5003
-   Furthermore, you can only run a function at compile time if it is imported
+   You can only run a function at compile time if it is imported
hunk ./docs/users_guide/glasgow_exts.xml 5005
-   that includes the module currently being compiled</emphasis>.  For example, when compiling module A,
+   that includes the module currently being compiled</emphasis>.  Furthermore, all of the modules of 
+   the mutually-recursive group must be reachable by non-SOURCE imports from the module where the
+   splice is to be run.</para>
+   <para>
+   For example, when compiling module A,
hunk ./docs/users_guide/glasgow_exts.xml 6381
-      Multi-level unpacking is also supported:</para>
+      Multi-level unpacking is also supported:
hunk ./docs/users_guide/glasgow_exts.xml 6388
-      <para>will store two unboxed <literal>Int&num;</literal>s
+      will store two unboxed <literal>Int&num;</literal>s
hunk ./docs/users_guide/glasgow_exts.xml 6402
+    <sect2 id="source-pragma">
+      <title>SOURCE pragma</title>
+
+      <indexterm><primary>SOURCE</primary></indexterm>
+     <para>The <literal>{-# SOURCE #-}</literal> pragma is used only in <literal>import</literal> declarations,
+     to break a module loop.  It is described in detail in <xref linkend="mutual-recursion"/>.
+     </para>
+</sect2>
+
hunk ./docs/users_guide/separate_compilation.xml 705
-circular dependency.  For every module <filename>A.hs</filename> that is <literal>{-# SOURCE #-}</literal>-imported
+circular dependency.  Every loop in the module import graph must be broken by a <literal>{-# SOURCE #-}</literal> import;
+or, equivalently, the module import graph must be acyclic if <literal>{-# SOURCE #-}</literal> imports are ignored.
+</para>
+<para>For every module <filename>A.hs</filename> that is <literal>{-# SOURCE #-}</literal>-imported
}