X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FbasicTypes%2FFieldLabel.lhs;h=ccaf094620116c2d4f42624f5174acb383c9e232;hb=fda89b29c748c6cd2fe1fdb477d5c0e8f7d32b90;hp=d8f61d33933b6e6eb95147f37f73e9627200d214;hpb=f9120c200bcf613b58d742802172fb4c08171f0d;p=ghc-hetmet.git

diff --git a/ghc/compiler/basicTypes/FieldLabel.lhs b/ghc/compiler/basicTypes/FieldLabel.lhs
index d8f61d3..ccaf094 100644
--- a/ghc/compiler/basicTypes/FieldLabel.lhs
+++ b/ghc/compiler/basicTypes/FieldLabel.lhs
@@ -8,17 +8,27 @@
 
 module FieldLabel where
 
-import Ubiq{-uitous-}
+IMP_Ubiq(){-uitous-}
 
-import Name		( Name{-instance Eq/Outputable-} )
-import Type		( Type(..) )
+import Name		( Name{-instance Eq/Outputable-}, NamedThing(..), nameUnique )
+import Type		( SYN_IE(Type) )
+
+import Outputable
+import Unique           ( Uniquable(..) )
 \end{code}
 
 \begin{code}
 data FieldLabel
-  = FieldLabel	Name
-		Type
-		FieldLabelTag
+  = FieldLabel	Name	        -- Also used as the Name of the field selector Id
+		Type		-- Type of the field; may have free type variables that
+				-- are the tyvar of the constructor
+				-- e.g.  data T a = MkT { op1 :: a -> a, op2 :: a -> Int }
+				-- The type in the FieldLabel for op1 will be simply (a->a).
+
+		FieldLabelTag	-- Indicates position within constructor
+				-- If the same field occurs in more than one constructor
+				-- then it'll have a separate FieldLabel on each occasion,
+				-- but with a single name (and presumably the same type!)
 
 type FieldLabelTag = Int
 
@@ -42,4 +52,7 @@ instance Outputable FieldLabel where
 
 instance NamedThing FieldLabel where
     getName (FieldLabel n _ _) = n
+
+instance Uniquable FieldLabel where
+    uniqueOf (FieldLabel n _ _) = nameUnique n
 \end{code}