[project @ 2003-12-30 14:05:46 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 bcf8195..3385adc 100644 (file)
--- a/ghc/compiler/types/Class.lhs
+++ b/ghc/compiler/types/Class.lhs
@@ -5,27 +5,24 @@
 
 \begin{code}
 module Class (
-       Class,
+       Class, ClassOpItem, FunDep,
+       DefMeth (..),
 
-       mkClass,
-       classKey, classSelIds, classTyCon,
-       classSuperClassTheta,
-       classBigSig, classInstEnv,
-
-       ClassInstEnv
+       mkClass, classTyVars, classArity,
+       classKey, className, classSelIds, classTyCon,
+       classBigSig, classExtraBigSig, classTvsFds, classSCTheta
     ) where
 
 #include "HsVersions.h"
 
 import {-# SOURCE #-} TyCon    ( TyCon )
-import {-# SOURCE #-} Type     ( Type )
-import {-# SOURCE #-} SpecEnv  ( SpecEnv )
+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}
 
 %************************************************************************
@@ -38,47 +35,56 @@ A @Class@ corresponds to a Greek kappa in the static semantics:
 
 \begin{code}
 data Class
-  = Class
-       Unique          -- Key for fast comparison
-       Name
-
-       [TyVar]                 -- The class type variables
-
-       [(Class,[Type])]        -- Immediate superclasses, and the
-       [Id]                    -- corresponding selector functions to
-                               -- extract them from a dictionary of this
-                               -- class
-
-       [Id]                    --       * selector functions
-       [Maybe Id]              --       * default methods
-                               -- They are all ordered by tag.  The
-                               -- selector ids contain unfoldings.
-
-       ClassInstEnv            -- All the instances of this class
-
-       TyCon                   -- The data type constructor for dictionaries
-                               -- of this class
-
-type ClassInstEnv = SpecEnv Id         -- The Ids are dfuns
+  = Class {
+       classKey  :: Unique,                    -- Key for fast comparison
+       className :: Name,
+       
+       classTyVars  :: [TyVar],                -- The class type variables
+       classFunDeps :: [FunDep TyVar],         -- The functional dependencies
+
+       classSCTheta :: [PredType],             -- Immediate superclasses, and the
+       classSCSels  :: [Id],                   -- corresponding selector functions to
+                                               -- extract them from a dictionary of this
+                                               -- class
+
+       classOpStuff :: [ClassOpItem],          -- Ordered by tag
+
+       classTyCon :: TyCon             -- The data type constructor for dictionaries
+  }                                    -- of this class
+
+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, DefMeth)
+       -- Selector function; contains unfolding
+       -- Default-method info
+
+data DefMeth = NoDefMeth               -- No default method
+            | DefMeth                  -- A polymorphic default method
+            | GenDefMeth               -- A generic default method
+             deriving Eq  
 \end{code}
 
 The @mkClass@ function fills in the indirect superclasses.
 
 \begin{code}
 mkClass :: Name -> [TyVar]
-       -> [(Class,[Type])] -> [Id]
-       -> [Id] -> [Maybe Id]
+       -> [([TyVar], [TyVar])]
+       -> [PredType] -> [Id]
+       -> [ClassOpItem]
        -> TyCon
-       -> ClassInstEnv
        -> Class
 
-mkClass name tyvars super_classes superdict_sels
-       dict_sels defms tycon class_insts
-  = Class (getUnique name) name tyvars
-         super_classes superdict_sels
-         dict_sels defms
-         class_insts
-         tycon
+mkClass name tyvars fds super_classes superdict_sels
+       op_stuff tycon
+  = Class {    classKey = getUnique name, 
+               className = name,
+               classTyVars = tyvars,
+               classFunDeps = fds,
+               classSCTheta = super_classes,
+               classSCSels = superdict_sels,
+               classOpStuff = op_stuff,
+               classTyCon = tycon }
 \end{code}
 
 %************************************************************************
@@ -90,14 +96,23 @@ mkClass name tyvars super_classes superdict_sels
 The rest of these functions are just simple selectors.
 
 \begin{code}
-classKey            (Class key _ _ _ _ _ _ _ _)  = key
-classSuperClassTheta (Class _ _ _ scs _ _ _ _ _)  = scs
-classSelIds         (Class _ _ _ _ _ sels _ _ _) = sels
-classTyCon          (Class _ _ _ _ _ _ _ _ tc)   = tc
-classInstEnv        (Class _ _ _ _ _ _ _ env _)  = env
-
-classBigSig (Class _ _ tyvars super_classes sdsels sels defms _ _)
-  = (tyvars, super_classes, sdsels, sels, defms)
+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]
+
+classTvsFds c
+  = (classTyVars c, classFunDeps c)
+
+classBigSig (Class {classTyVars = tyvars, classSCTheta = sc_theta, 
+                   classSCSels = sc_sels, classOpStuff = op_stuff})
+  = (tyvars, sc_theta, sc_sels, op_stuff)
+classExtraBigSig (Class {classTyVars = tyvars, classFunDeps = fundeps,
+                        classSCTheta = sc_theta, classSCSels = sc_sels,
+                        classOpStuff = op_stuff})
+  = (tyvars, fundeps, sc_theta, sc_sels, op_stuff)
 \end{code}
 
 
@@ -127,13 +142,18 @@ instance Uniquable Class where
     getUnique c = classKey c
 
 instance NamedThing Class where
-    getName (Class _ n _ _ _ _ _ _ _) = n
+    getName clas = className clas
 
 instance Outputable Class where
     ppr c = ppr (getName c)
 
 instance Show Class where
     showsPrec p c = showsPrecSDoc p (ppr c)
+
+instance Outputable DefMeth where
+    ppr DefMeth     =  text "{- has default method -}"
+    ppr GenDefMeth  =  text "{- has generic method -}"
+    ppr NoDefMeth   =  empty   -- No default method
 \end{code}