[project @ 2001-10-16 10:50:11 by simonmar]

mention that identifiers beginning with a double underscore are to be
avoided in -fglasgow-exts mode.

diff --git a/ghc/docs/users_guide/vs_haskell.sgml b/ghc/docs/users_guide/vs_haskell.sgml
index e7e922a..7e0cc47 100644 (file)
--- a/ghc/docs/users_guide/vs_haskell.sgml
+++ b/ghc/docs/users_guide/vs_haskell.sgml
@@ -36,6 +36,16 @@
          single qualified operator rather than the two lexemes
          <literal>M</literal> and <literal>.\</literal>.</para>
        </listitem>
+
+       <listitem>
+         <para>When <option>-fglasgow-exts</option> is on, GHC
+         reserves several keywords beginning with two underscores.
+         This is due to the fact that GHC uses the same lexical
+         analyser for interface file parsing as it does for source
+         file parsing, and these keywords are used in interface
+         files.  Do not use any identifiers beginning with a double
+         underscore in <option>-fglasgow-exts</option> mode.</para>
+       </listitem>
       </itemizedlist>
     </sect3>