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{-# OPTIONS_GHC -Wall #-} ------------------------------------------------------------------------------- {- | Module : Language.Type.Utils Description : Useful functions for dealing with type representation. Copyright : (c) Paulo Silva License : LGPL Maintainer : paufil@di.uminho.pt Stability : experimental Portability : portable -} ------------------------------------------------------------------------------- module Language.Type.Utils ( isBasicType, isBasicTypeTB, isTVar, isTVarTB, occursIn, occursInTB, isConstructor, collectTVar, collectTVarTB, getTVarNameTB ) where import Data.Existential import Language.Type.Syntax ------------------------------------------------------------------------------- isBasicType :: Type a -> Bool isBasicType One = True isBasicType Bool = True isBasicType Char = True isBasicType String = True isBasicType Int = True isBasicType Float = True isBasicType _ = False ------------------------------------------------------------------------------- isBasicTypeTB :: TypeBox -> Bool isBasicTypeTB (Hide t) = isBasicType t ------------------------------------------------------------------------------- isTVar :: Type a -> Bool isTVar (TVar _) = True isTVar _ = False ------------------------------------------------------------------------------- isTVarTB :: TypeBox -> Bool isTVarTB (Hide t) = isTVar t ------------------------------------------------------------------------------- occursIn :: Type a -> Type b -> Bool occursIn t (Prod a b) = occursIn t a || occursIn t b occursIn t (Either a b) = occursIn t a || occursIn t b occursIn t (Maybe a) = occursIn t a occursIn t (List a) = occursIn t a occursIn t (Set a) = occursIn t a occursIn t (Map a b) = occursIn t a || occursIn t b occursIn t (Fun a b) = occursIn t a || occursIn t b occursIn t (Rel a b) = occursIn t a || occursIn t b occursIn t (Ord a) = occursIn t a occursIn t (GC a b) = occursIn t a || occursIn t b occursIn (TVar n) (TVar m) = n == m occursIn _ _ = False ------------------------------------------------------------------------------- occursInTB :: TypeBox -> TypeBox -> Bool occursInTB (Hide a) (Hide b) = a `occursIn` b ------------------------------------------------------------------------------- isConstructor :: Type a -> Bool isConstructor t = not (isBasicType t) && not (isTVar t) ------------------------------------------------------------------------------- collectTVar :: Type a -> [TypeBox] collectTVar x@(TVar _) = [Hide x] collectTVar (Prod a b) = collectTVar a ++ collectTVar b collectTVar (List a) = collectTVar a collectTVar (Either a b) = collectTVar a ++ collectTVar b collectTVar (Maybe a) = collectTVar a collectTVar (Set a) = collectTVar a collectTVar (Ord a) = collectTVar a collectTVar (Map a b) = collectTVar a ++ collectTVar b collectTVar (Fun a b) = collectTVar a ++ collectTVar b collectTVar (GC a b) = collectTVar a ++ collectTVar b collectTVar _ = [] ------------------------------------------------------------------------------- collectTVarTB :: TypeBox -> [TypeBox] collectTVarTB (Hide t) = collectTVar t ------------------------------------------------------------------------------- getTVarNameTB :: TypeBox -> String getTVarNameTB (Hide (TVar n)) = n getTVarNameTB _ = "" ------------------------------------------------------------------------------- |