[project @ 2000-11-03 17:10:57 by simonpj]

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

diff --git a/ghc/compiler/types/InstEnv.lhs b/ghc/compiler/types/InstEnv.lhs
index 90ae4c1..7ca6cf6 100644 (file)
--- a/ghc/compiler/types/InstEnv.lhs
+++ b/ghc/compiler/types/InstEnv.lhs
@@ -7,18 +7,18 @@ The bits common to TcInstDcls and TcDeriv.
 
 \begin{code}
 module InstEnv (
-       -- Instance environment
-       InstEnv, emptyInstEnv, extendInstEnv,
+       DFunId, ClsInstEnv, InstEnv,
+
+       emptyInstEnv, extendInstEnv,
        lookupInstEnv, InstLookupResult(..),
-       classInstEnv, classDataCon, simpleDFunClassTyCon
+       classInstEnv, simpleDFunClassTyCon
     ) where
 
 #include "HsVersions.h"
 
-import HscTypes                ( InstEnv, ClsInstEnv, DFunId )
 import Class           ( Class )
 import Var             ( Id )
-import VarSet          ( unionVarSet, mkVarSet )
+import VarSet          ( TyVarSet, unionVarSet, mkVarSet )
 import VarEnv          ( TyVarSubstEnv )
 import Maybes          ( MaybeErr(..), returnMaB, failMaB, thenMaB, maybeToBool )
 import Name            ( getSrcLoc )
@@ -26,23 +26,30 @@ import Type         ( Type, splitTyConApp_maybe,
                          splitSigmaTy, splitDFunTy, tyVarsOfTypes
                        )
 import PprType         ( )
-import Class           ( classTyCon )
 import DataCon         ( DataCon )
-import TyCon           ( TyCon, tyConDataCons )
+import TyCon           ( TyCon )
 import Outputable
 import Unify           ( matchTys, unifyTyListsX )
-import UniqFM          ( lookupWithDefaultUFM, addToUFM, emptyUFM )
+import UniqFM          ( UniqFM, lookupWithDefaultUFM, addToUFM, emptyUFM )
 import Id              ( idType )
 import ErrUtils                ( Message )
 import CmdLineOpts
 \end{code}
 
 
-
-A tiny function which doesn't belong anywhere else.
-It makes a nasty mutual-recursion knot if you put it in Class.
+%************************************************************************
+%*                                                                     *
+\subsection{The key types}
+%*                                                                     *
+%************************************************************************
 
 \begin{code}
+type DFunId    = Id
+
+type InstEnv    = UniqFM ClsInstEnv            -- Maps Class to instances for that class
+
+type ClsInstEnv = [(TyVarSet, [Type], DFunId)] -- The instances for a particular class
+
 simpleDFunClassTyCon :: DFunId -> (Class, TyCon)
 simpleDFunClassTyCon dfun
   = (clas, tycon)
@@ -50,10 +57,6 @@ simpleDFunClassTyCon dfun
     (_,_,clas,[ty]) = splitDFunTy (idType dfun)
     tycon          = case splitTyConApp_maybe ty of
                        Just (tycon,_) -> tycon
-
-classDataCon :: Class -> DataCon
-classDataCon clas = case tyConDataCons (classTyCon clas) of
-                     (dict_constr:no_more) -> ASSERT( null no_more ) dict_constr 
 \end{code}                   
 
 %************************************************************************