\begin{code}
module Class (
- Class, ClassOpItem, ClassPred, ClassContext, FunDep,
+ Class, ClassOpItem, FunDep,
DefMeth (..),
mkClass, classTyVars, classArity,
classKey, className, classSelIds, classTyCon,
- classBigSig, classExtraBigSig, classTvsFds
+ classBigSig, classExtraBigSig, classTvsFds, classSCTheta,
+ classHasFDs
) 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 ( notNull )
\end{code}
%************************************************************************
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
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, DefMeth Id)
+type ClassOpItem = (Id, DefMeth Name)
-- Selector function; contains unfolding
-- Default-method info
data DefMeth id = NoDefMeth -- No default method
| DefMeth id -- A polymorphic default method (named id)
+ -- (Only instantiated to RdrName and Name, never Id)
| GenDefMeth -- A generic default method
deriving Eq
\end{code}
\begin{code}
mkClass :: Name -> [TyVar]
-> [([TyVar], [TyVar])]
- -> [(Class,[Type])] -> [Id]
+ -> [PredType] -> [Id]
-> [ClassOpItem]
-> TyCon
-> Class
classSCTheta = sc_theta, classSCSels = sc_sels,
classOpStuff = op_stuff})
= (tyvars, fundeps, sc_theta, sc_sels, op_stuff)
+
+classHasFDs :: Class -> Bool
+classHasFDs (Class {classFunDeps = fundeps}) = notNull fundeps
\end{code}