[project @ 2000-10-05 15:33:03 by simonpj]

Add a bit more documentation of generics

diff --git a/ghc/docs/users_guide/glasgow_exts.sgml b/ghc/docs/users_guide/glasgow_exts.sgml
index 7cb23c0..b52adc9 100644 (file)
--- a/ghc/docs/users_guide/glasgow_exts.sgml
+++ b/ghc/docs/users_guide/glasgow_exts.sgml
@@ -4279,6 +4279,22 @@ That is, just leave off the "where" clasuse.  Of course, you can put in the
 where clause and over-ride whichever methods you please.
 
 
+<Sect2> <Title> Using generics </Title>
+</Sect2>
+<Para>
+To use generics you need to
+<ItemizedList>
+<ListItem>
+Use the <Option>-fgenerics</Option> flag.
+</ListItem>
+<ListItem>
+Import the module <Literal>Generics</Literal> from the <Literal>lang</Literal> package.
+This import brings into scope the data types <Literal>Unit</Literal>, <Literal>:*:</Literal>, 
+and <Literal>:+:</Literal>.  (You don't need this import if you don't mention these
+types explicitly; for example, if you are simply giving instance declarations.)
+</ListItem>
+</ItemizedList>
+
 <Sect2> <Title> Changes wrt the paper </Title>
 <Para>
 Note that the type constructors <Literal>:+:</Literal> and <Literal>:*:</Literal>