X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=docs%2Fusers_guide%2Fglasgow_exts.xml;h=c370ce3388308a602a0f020a8745652fed0b5d3e;hb=2ab65c00417e668f8a2a3f98fde51448dda83d6e;hp=09fd3f509fd4efbab42e79ee8ffaa3e7e508f797;hpb=bebf54b1fefef0c337955ec1e653b44f4ec63d10;p=ghc-hetmet.git
diff --git a/docs/users_guide/glasgow_exts.xml b/docs/users_guide/glasgow_exts.xml
index 09fd3f5..c370ce3 100644
--- a/docs/users_guide/glasgow_exts.xml
+++ b/docs/users_guide/glasgow_exts.xml
@@ -106,9 +106,7 @@ documentation describes all the libraries that come with GHC.
This option enables the language extension defined in the
- Haskell 98 Foreign Function Interface Addendum plus deprecated
- syntax of previous versions of the FFI for backwards
- compatibility.
+ Haskell 98 Foreign Function Interface Addendum.
New reserved words: foreign.
@@ -116,7 +114,7 @@ documentation describes all the libraries that come with GHC.
- ,:
+ ,:
These two flags control how generalisation is done.
@@ -3301,6 +3299,7 @@ changing the program.
A lexically scoped type variable can be bound by:
A declaration type signature ()
+An expression type signature ()A pattern type signature ()Class and instance declarations ()
@@ -3352,6 +3351,23 @@ quantification rules.
+
+Expression type signatures
+
+An expression type signature that has explicit
+quantification (using forall) brings into scope the
+explicitly-quantified
+type variables, in the annotated expression. For example:
+
+ f = runST ( (op >>= \(x :: STRef s Int) -> g x) :: forall s. ST s Bool )
+
+Here, the type signature forall a. ST s Bool brings the
+type variable s into scope, in the annotated expression
+(op >>= \(x :: STRef s Int) -> g x).
+
+
+
+
Pattern type signatures
@@ -3709,6 +3725,33 @@ the standard method is used or the one described here.)
+
+Stand-alone deriving declarations
+
+
+GHC now allows stand-alone deriving declarations:
+
+
+
+ data Foo = Bar Int | Baz String
+
+ deriving Eq for Foo
+
+
+Deriving instances of multi-parameter type classes for newtypes is
+also allowed:
+
+
+ newtype Foo a = MkFoo (State Int a)
+
+ deriving (MonadState Int) for Foo
+
+
+
+
+
+
+
Generalised typing of mutually recursive bindings