[project @ 2001-03-13 14:58:25 by simonpj]

[ghc-hetmet.git] / ghc / compiler / types / Class.lhs

diff --git a/ghc/compiler/types/Class.lhs b/ghc/compiler/types/Class.lhs
index a04cdcc..3ecb8f8 100644 (file)
--- a/ghc/compiler/types/Class.lhs
+++ b/ghc/compiler/types/Class.lhs
@@ -5,23 +5,24 @@
 
 \begin{code}
 module Class (
-       Class, ClassOpItem, ClassPred, ClassContext, FunDep,
+       Class, ClassOpItem, FunDep,
+       DefMeth (..),
 
-       mkClass, classTyVars,
+       mkClass, classTyVars, classArity,
        classKey, className, classSelIds, classTyCon,
-       classBigSig, classExtraBigSig, classTvsFds
+       classBigSig, classExtraBigSig, classTvsFds, classSCTheta
     ) where
 
 #include "HsVersions.h"
 
 import {-# SOURCE #-} TyCon    ( TyCon )
-import {-# SOURCE #-} TypeRep  ( Type )
+import {-# SOURCE #-} TypeRep  ( PredType )
 
 import Var             ( Id, TyVar )
 import Name            ( NamedThing(..), Name )
+import BasicTypes      ( Arity )
 import Unique          ( Unique, Uniquable(..) )
 import Outputable
-import Util
 \end{code}
 
 %************************************************************************
@@ -41,7 +42,7 @@ data Class
        classTyVars  :: [TyVar],                -- The class type variables
        classFunDeps :: [FunDep TyVar],         -- The functional dependencies
 
-       classSCTheta :: [(Class,[Type])],       -- Immediate superclasses, and the
+       classSCTheta :: [PredType],             -- Immediate superclasses, and the
        classSCSels  :: [Id],                   -- corresponding selector functions to
                                                -- extract them from a dictionary of this
                                                -- class
@@ -51,16 +52,17 @@ data Class
        classTyCon :: TyCon             -- The data type constructor for dictionaries
   }                                    -- of this class
 
-type ClassPred           = (Class, [Type])
-type ClassContext = [ClassPred]
-
 type FunDep a    = ([a],[a])   --  e.g. class C a b c |  a b -> c, a c -> b  where ...
                                --  Here fun-deps are [([a,b],[c]), ([a,c],[b])]
 
-type ClassOpItem = (Id,        --   Selector function; contains unfolding
-                   Id,         --   Default methods
-                   Bool)       --   True <=> an explicit default method was 
-                               --            supplied in the class decl
+type ClassOpItem = (Id, DefMeth Id)
+       -- Selector function; contains unfolding
+       -- Default-method info
+
+data DefMeth id = NoDefMeth            -- No default method
+               | DefMeth id            -- A polymorphic default method (named id)
+               | GenDefMeth            -- A generic default method
+                deriving Eq  
 \end{code}
 
 The @mkClass@ function fills in the indirect superclasses.
@@ -68,8 +70,8 @@ The @mkClass@ function fills in the indirect superclasses.
 \begin{code}
 mkClass :: Name -> [TyVar]
        -> [([TyVar], [TyVar])]
-       -> [(Class,[Type])] -> [Id]
-       -> [(Id, Id, Bool)]
+       -> [PredType] -> [Id]
+       -> [ClassOpItem]
        -> TyCon
        -> Class
 
@@ -94,8 +96,12 @@ mkClass name tyvars fds super_classes superdict_sels
 The rest of these functions are just simple selectors.
 
 \begin{code}
+classArity :: Class -> Arity
+classArity clas = length (classTyVars clas)
+       -- Could memoise this
+
 classSelIds (Class {classSCSels = sc_sels, classOpStuff = op_stuff})
-  = sc_sels ++ [op_sel | (op_sel, _, _) <- op_stuff]
+  = sc_sels ++ [op_sel | (op_sel, _) <- op_stuff]
 
 classTvsFds c
   = (classTyVars c, classFunDeps c)