[project @ 2000-10-30 17:18:26 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 781e342..3553763 100644 (file)
--- a/ghc/compiler/types/Class.lhs
+++ b/ghc/compiler/types/Class.lhs
@@ -6,23 +6,23 @@
 \begin{code}
 module Class (
        Class, ClassOpItem, ClassPred, ClassContext, FunDep,
+       DefMeth (..),
 
-       mkClass, classTyVars,
+       mkClass, classTyVars, classArity,
        classKey, className, classSelIds, classTyCon,
-       classBigSig, classExtraBigSig, classInstEnv, classTvsFds
+       classBigSig, classExtraBigSig, classTvsFds
     ) where
 
 #include "HsVersions.h"
 
 import {-# SOURCE #-} TyCon    ( TyCon )
 import {-# SOURCE #-} TypeRep  ( Type )
-import {-# SOURCE #-} InstEnv  ( InstEnv )
 
 import Var             ( Id, TyVar )
 import Name            ( NamedThing(..), Name )
+import BasicTypes      ( Arity )
 import Unique          ( Unique, Uniquable(..) )
 import Outputable
-import Util
 \end{code}
 
 %************************************************************************
@@ -49,8 +49,6 @@ data Class
 
        classOpStuff :: [ClassOpItem],          -- Ordered by tag
 
-       classInstEnv :: InstEnv,        -- All the instances of this class
-
        classTyCon :: TyCon             -- The data type constructor for dictionaries
   }                                    -- of this class
 
@@ -60,10 +58,14 @@ 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.
@@ -72,13 +74,12 @@ The @mkClass@ function fills in the indirect superclasses.
 mkClass :: Name -> [TyVar]
        -> [([TyVar], [TyVar])]
        -> [(Class,[Type])] -> [Id]
-       -> [(Id, Id, Bool)]
+       -> [ClassOpItem]
        -> TyCon
-       -> InstEnv
        -> Class
 
 mkClass name tyvars fds super_classes superdict_sels
-       op_stuff tycon class_insts
+       op_stuff tycon
   = Class {    classKey = getUnique name, 
                className = name,
                classTyVars = tyvars,
@@ -86,7 +87,6 @@ mkClass name tyvars fds super_classes superdict_sels
                classSCTheta = super_classes,
                classSCSels = superdict_sels,
                classOpStuff = op_stuff,
-               classInstEnv = class_insts,
                classTyCon = tycon }
 \end{code}
 
@@ -99,8 +99,12 @@ 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)