[project @ 2005-02-17 14:41:36 by simonmar]

Mention GHC's relaxation of the layout rule

diff --git a/ghc/docs/users_guide/bugs.xml b/ghc/docs/users_guide/bugs.xml
index 0bdb38c..f9fc964 100644 (file)
--- a/ghc/docs/users_guide/bugs.xml
+++ b/ghc/docs/users_guide/bugs.xml
@@ -46,7 +46,27 @@
       <sect3 id="infelicities-syntax">
        <title>Context-free syntax</title>
        
-      <itemizedlist>
+       <itemizedlist>
+         <listitem>
+           <para>GHC is a little less strict about the layout rule when used
+             in <literal>do</literal> expressions.  Specifically, the
+             restriction that "a nested context must be indented further to
+             the right than the enclosing context" is relaxed to allow the
+             nested context to be at the same level as the enclosing context,
+             if the enclosing context is a <literal>do</literal>
+             expression.</para>
+
+           <para>For example, the following code is accepted by GHC:
+
+<programlisting>
+main = do args &lt;- getArgs
+         if null args then return [] else do
+          ps &lt;- mapM process args
+          mapM print ps</programlisting>
+
+             </para>
+         </listitem>
+
        <listitem>
          <para>GHC doesn't do fixity resolution in expressions during
          parsing.  For example, according to the Haskell report, the