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remove some dead types from GF.Grammar.Grammar

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krasimir
2009-01-20 14:33:42 +00:00
parent d6e917b5a1
commit e3892b82c0
5 changed files with 10 additions and 19 deletions
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14
src/GF/Grammar/Unify.hs
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@@ -38,8 +38,8 @@ unifyVal cs0 = do
(_,VClos (_:_) _) -> True
_ -> False
type Unifier = [(MetaSymb, Trm)]
type Constrs = [(Trm, Trm)]
type Unifier = [(MetaSymb, Term)]
type Constrs = [(Term, Term)]
unifyAll :: Constrs -> Unifier -> (Unifier,Constrs)
unifyAll [] g = (g, [])
@@ -49,7 +49,7 @@ unifyAll ((a@(s, t)) : l) g =
Ok g2 -> (g2, c)
_ -> (g1, a : c)
unify :: Trm -> Trm -> Unifier -> Err Unifier
unify :: Term -> Term -> Unifier -> Err Unifier
unify e1 e2 g =
case (e1, e2) of
(Meta s, t) -> do
@@ -67,12 +67,12 @@ unify e1 e2 g =
_ -> prtBad "fail unify" e1
_ -> prtBad "fail unify" e1
extend :: Unifier -> MetaSymb -> Trm -> Err Unifier
extend :: Unifier -> MetaSymb -> Term -> Err Unifier
extend g s t | (t == Meta s) = return g
| occCheck s t = prtBad "occurs check" t
| True = return ((s, t) : g)
subst_all :: Unifier -> Trm -> Err Trm
subst_all :: Unifier -> Term -> Err Term
subst_all s u =
case (s,u) of
([], t) -> return t
@@ -80,14 +80,14 @@ subst_all s u =
t' <- (subst_all l t) --- successive substs - why ?
return $ substMetas [a] t'
substMetas :: [(MetaSymb,Trm)] -> Trm -> Trm
substMetas :: [(MetaSymb,Term)] -> Term -> Term
substMetas subst trm = case trm of
Meta x -> case lookup x subst of
Just t -> t
_ -> trm
_ -> composSafeOp (substMetas subst) trm
occCheck :: MetaSymb -> Trm -> Bool
occCheck :: MetaSymb -> Term -> Bool
occCheck s u = case u of
Meta v -> s == v
App c a -> occCheck s c || occCheck s a