import Data.Either
import Data.Func
import Data.List
+import Data.Tuple
import Data.Map => qualified put, union, difference, find, updateAt
import Data.Maybe
-import Data.Tuple
import Text
import ast, scc
-import Text.GenPrint
import StdDebug
-check :: [Function] -> Either [String] (Expression, [([Char], Scheme)])
-check fs
- # dups = filter (\x->length x > 1) (groupBy (\(Function i _ _) (Function j _ _)->i == j) fs)
+check :: ![Either TypeDef Function] -> Either [String] (Expression, [([Char], Scheme)])
+check tdfs
+ # dups = filter (\x->length x > 1) (groupBy (\(Function i _ _) (Function j _ _)->i == j) functions)
| length dups > 0 = Left ["Duplicate functions: ":[toString n\\[(Function n _ _):_]<-dups]]
- = case partition (\a->a=:(Function ['start'] _ _)) fs of
+ = case partition (\a->a=:(Function ['start'] _ _)) functions of
([], _) = Left ["No start function defined"]
- ([Function _ [] e], fs)
- = (\x->(e, x)) <$> runInfer (infer preamble (makeExpression fs e))
- ([Function _ _ _], _) = Left ["Start cannot have arguments"]
+ ([Function _ [] e:_], fs)
+ # e = makeExpression fs e
+ = tuple e <$> runInfer (infer (fromList (conses ++ builtin)) e)
+ ([Function _ _ _:_], _) = Left ["Start cannot have arguments"]
+where
+ functions = rights tdfs
+ conses = flatten $ map (\(TypeDef n t cs)->
+ let cons = Forall t o foldr (-->) (foldl TApp (TVar n) (map TVar t))
+ in map (appSnd cons) cs) $ lefts tdfs
+ builtin =
+ [(['_if'], Forall [['a']] $ TBool --> TVar ['a'] --> TVar ['a'] --> TVar ['a'])
+ ,(['_eq'], Forall [] $ TInt --> TInt --> TBool)
+ ,(['_mul'], Forall [] $ TInt --> TInt --> TInt)
+ ,(['_add'], Forall [] $ TInt --> TInt --> TInt)
+ ,(['_sub'], Forall [] $ TInt --> TInt --> TInt)
+ ,(['_div'], Forall [] $ TInt --> TInt --> TInt)
+ ]
makeExpression :: [Function] Expression -> Expression
-makeExpression fs start
- = foldr mkExpr start $ scc [(l, vars e [])\\(l, e)<-nicefuns]
+makeExpression fs start = foldr mkExpr start $ scc $ map (appSnd vars) nicefuns
where
mkExpr :: [[Char]] -> (Expression -> Expression)
mkExpr scc = Let [(l, e)\\(l, e)<-nicefuns, s<-scc | s == l]
nicefuns :: [([Char], Expression)]
nicefuns = [(l, foldr ((o) o Lambda) id i e)\\(Function l i e)<-fs]
- vars :: Expression [[Char]] -> [[Char]]
- vars (Var v=:[m:_]) c = [v:c]
- vars (App l r) c = vars l $ vars r c
- vars (Lambda l e) c = [v\\v<-vars e c | v <> l]
- vars (Let ns e) c = flatten
- [ [v\\v<-vars e c | not (isMember v (map fst ns))]
- : map (\(i, e)->[v\\v<-vars e [] | v <> i]) ns]
- vars _ c = c
+ vars :: Expression -> [[Char]]
+ vars (Var v) = [v]
+ vars (App l r) = vars l ++ vars r
+ vars (Lambda l e) = flt l e
+ vars (Let ns e) = flatten [[v\\v<-vars e | not (isMember v (map fst ns))]:map (uncurry flt) ns]
+ vars _ = []
+
+ flt i e = [v\\v<-vars e | v <> i]
instance toString Scheme where
toString (Forall [] t) = toString t
toString (Forall as t) = concat ["A.", join " " (map toString as), ": ", toString t]
-instance toString Type where
- toString (TVar a) = toString a
- toString TInt = "Int"
- toString TBool = "Bool"
- toString (a --> b) = concat ["(", toString a, ") -> ", toString b]
-
:: TypeEnv :== Map [Char] Scheme
-preamble :: TypeEnv
-preamble = fromList
- [(['_if'], Forall [['_ift']]
- $ TBool --> TVar ['_ift'] --> TVar ['_ift'] --> TVar ['_ift'])
- ,(['_eq'], Forall [['_eq']] $ TInt --> TInt --> TBool)
- ,(['_mul'], Forall [['_mul']] $ TInt --> TInt --> TInt)
- ,(['_add'], Forall [['_add']] $ TInt --> TInt --> TInt)
- ,(['_sub'], Forall [['_sub']] $ TInt --> TInt --> TInt)
- ]
:: Subst :== Map [Char] Type
:: Infer a :== StateT [Int] (WriterT [([Char], Scheme)] (Either [String])) a
+
runInfer :: (Infer (Subst, Type)) -> Either [String] [([Char], Scheme)]
runInfer i = case runWriterT (evalStateT i [0..]) of
Left e = Left e
instance Substitutable Type where
apply s t=:(TVar v) = fromMaybe t (get v s)
apply s (t1 --> t2) = apply s t1 --> apply s t2
+ apply s (TApp t1 t2) = TApp (apply s t1) (apply s t2)
apply _ x = x
ftv (TVar v) = [v]
ftv (t1 --> t2) = on union ftv t1 t2
+ ftv (TApp t1 t2) = on union ftv t1 t2
ftv _ = []
instance Substitutable Scheme where
unify t (TVar a) = unify (TVar a) t
unify TInt TInt = pure newMap
unify TBool TBool = pure newMap
+unify (TApp l r) (TApp l` r`)
+ = unify l l`
+ >>= \s1->on unify (apply s1) r r`
+ >>= \s2->pure (s1 oo s2)
unify t1 t2 = err ["Cannot unify: ", toString t1, " with ", toString t2]
unifyl :: [Type] -> Infer Subst
infer :: TypeEnv Expression -> Infer (Subst, Type)
infer env (Lit (Int _)) = pure (newMap, TInt)
infer env (Lit (Bool _)) = pure (newMap, TBool)
-infer env (Var x) = case get x env of
- Nothing = err ["Unbound variable: ", toString x]
- Just s = (\x->(newMap, x)) <$> instantiate s
+infer env (Var x) = maybe (err ["Unbound variable: ", toString x])
+ (\s->tuple newMap <$> instantiate s) $ get x env
infer env (App e1 e2)
= fresh
>>= \tv-> infer env e1
>>= \(s1, t1)->infer (apply s1 env) e2
>>= \(s2, t2)->unify (apply s2 t1) (t2 --> tv)
- >>= \s3-> pure (s1 oo s2 oo s3, apply s3 tv)
+ >>= \s3-> pure (s3 oo s2 oo s1, apply s3 tv)
infer env (Lambda x b)
= fresh
>>= \tv-> infer ('Data.Map'.put x (Forall [] tv) env) b
//infer env (Let [(x, e1)] e2)
// = infer env e1
// >>= \(s1, t1)->infer ('Data.Map'.put x (generalize (apply s1 env) t1) env) e2
-// >>= \(s2, t2)->pure (s1 oo s2, t2)
+// >>= \(s2, t2)->liftT (tell [(x, Forall [] t1)])
+// >>| pure (s1 oo s2, t2)
//Single recursion
//infer env (Let [(x, e1)] e2)
// = fresh
in unzip <$> sequence (map (infer env`) bs)
>>= \(ss,ts)-> unifyl ts
>>= \s-> liftT (tell [(n, generalize (apply s env`) t)\\t<-ts & n<-ns])
- >>| let env`` = foldr (\(n, t) m->'Data.Map'.put n (generalize (apply s env`) t) m) env` (zip2 ns ts)
+ >>| let env`` = foldr (\(n, s, t) m->'Data.Map'.put n (generalize (apply s env`) t) m) env` (zip3 ns ss ts)
in infer env`` e2
>>= \(s2, t2)->pure (s oo s2, t2)
repositories / minfp.git / blobdiff