Document GADTSyntax extension

diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml
index 2bcb5e6..a9c0184 100644 (file)
--- a/docs/users_guide/flags.xml
+++ b/docs/users_guide/flags.xml
@@ -763,6 +763,13 @@
              <entry><option>-XNoGADTs</option></entry>
            </row>
            <row>
              <entry><option>-XNoGADTs</option></entry>
            </row>
            <row>

+             <entry><option>-XGADTSyntax</option></entry>
+             <entry>Enable <link linkend="gadt-style">generalised algebraic data type syntax</link>.
+             </entry>
+             <entry>dynamic</entry>
+             <entry><option>-XNoGADTSyntax</option></entry>
+           </row>
+           <row>

              <entry><option>-XTypeFamilies</option></entry>
              <entry>Enable <link linkend="type-families">type families</link>.</entry>
              <entry>dynamic</entry>
              <entry><option>-XTypeFamilies</option></entry>
              <entry>Enable <link linkend="type-families">type families</link>.</entry>
              <entry>dynamic</entry>

diff --git a/docs/users_guide/glasgow_exts.xml b/docs/users_guide/glasgow_exts.xml
index a193088..ddbd2ec 100644 (file)
--- a/docs/users_guide/glasgow_exts.xml
+++ b/docs/users_guide/glasgow_exts.xml
@@ -2434,7 +2434,8 @@ declarations.  Define your own instances!
 <sect2 id="gadt-style">
 <title>Declaring data types with explicit constructor signatures</title>
 
 <sect2 id="gadt-style">
 <title>Declaring data types with explicit constructor signatures</title>
 

-<para>GHC allows you to declare an algebraic data type by 
+<para>When the <literal>GADTSyntax</literal> extension is enabled,
+GHC allows you to declare an algebraic data type by

 giving the type signatures of constructors explicitly.  For example:
 <programlisting>
   data Maybe a where
 giving the type signatures of constructors explicitly.  For example:
 <programlisting>
   data Maybe a where