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Made the key type in the type unification generic (as long as it provides Ord and Show)

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This commit is contained in:
Neil Brown 2008-05-14 12:06:11 +00:00
parent e09fb2b9ec
commit e3bf321f33
1 changed files with 6 additions and 7 deletions
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13
frontends/TypeUnification.hs
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@ -41,8 +41,8 @@ foldCon con _ = Left "foldCon: too many arguments given"
-- Pearl (2001)", citeseer: http://citeseer.ist.psu.edu/451401.html
-- This in turn was taken from Luca Cardelli's "Basic Polymorphic Type Checking"
unifyRainTypes :: Map.Map String A.Type -> [(String, String)] -> Either String
(Map.Map String A.Type)
unifyRainTypes :: forall k. (Ord k, Show k) => Map.Map k A.Type -> [(k, k)] -> Either String
(Map.Map k A.Type)
unifyRainTypes m prs
= runST $ do m' <- mapToST m
outs <- mapM (\(x,y) -> unifyType (lookupStartType x m') (lookupStartType y
@ -51,18 +51,17 @@ unifyRainTypes m prs
(err:_) -> return $ Left err
[] -> stToMap m'
where
lookupStartType :: String -> Map.Map String (TypeExp s A.Type) -> TypeExp
lookupStartType :: k -> Map.Map k (TypeExp s A.Type) -> TypeExp
s A.Type
lookupStartType s m = case Map.lookup s m of
Just x -> x
Nothing -> error $ "Could not find type for variable in map before unification: "
++ s
++ show s
mapToST :: Map.Map String A.Type -> ST s (Map.Map String (TypeExp s A.Type))
mapToST :: Map.Map k A.Type -> ST s (Map.Map k (TypeExp s A.Type))
mapToST = mapMapM typeToTypeExp
stToMap :: Map.Map String (TypeExp s A.Type) -> ST s (Either String (Map.Map String
A.Type))
stToMap :: Map.Map k (TypeExp s A.Type) -> ST s (Either String (Map.Map k A.Type))
stToMap m = do m' <- mapMapM (read <.< prune) m
let (mapOfErrs, mapOfRes) = Map.mapEitherWithKey (const id) m'
case Map.elems mapOfErrs of