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the type checker for the abstract syntax now allows let expressions in def rules, since they are easily compilable to byte code. This fails in the Haskell runtime since let expressions are not allowed as abstract syntax expressions.

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kr.angelov
2014-09-17 21:59:45 +00:00
parent db68456727
commit ff45e7dd3a
1 changed files with 20 additions and 0 deletions
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20
src/compiler/GF/Compile/TypeCheck/TC.hs
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@@ -38,6 +38,7 @@ data AExp =
| AFloat Double
| AStr String
| AMeta MetaId Val
| ALet (Ident,(Val,AExp)) AExp
| AApp AExp AExp Val
| AAbs Ident Val AExp
| AProd Ident AExp AExp
@@ -131,6 +132,16 @@ checkExp th tenv@(k,rho,gamma) e ty = do
return (AAbs x a' t', cs)
_ -> Bad (render ("function type expected for" <+> ppTerm Unqualified 0 e <+> "instead of" <+> ppValue Unqualified 0 typ))
Let (x, (mb_typ, e1)) e2 -> do
(val,e1,cs1) <- case mb_typ of
Just typ -> do val <- eval rho typ
(e1,cs) <- checkExp th tenv e1 val
return (val,e1,cs)
Nothing -> do (e1,val,cs) <- inferExp th tenv e1
return (val,e1,cs)
(e2,cs2) <- checkExp th (k,rho,(x,val):gamma) e2 typ
return (ALet (x,(val,e1)) e2, cs1++cs2)
Prod _ x a b -> do
testErr (typ == vType) "expected Type"
(a',csa) <- checkType th tenv a
@@ -172,6 +183,15 @@ inferExp th tenv@(k,rho,gamma) e = case e of
RecType xs -> do r <- mapM (checkLabelling th tenv) xs
let (xs,css) = unzip r
return (ARecType xs, vType, concat css)
Let (x, (mb_typ, e1)) e2 -> do
(val1,e1,cs1) <- case mb_typ of
Just typ -> do val <- eval rho typ
(e1,cs) <- checkExp th tenv e1 val
return (val,e1,cs)
Nothing -> do (e1,val,cs) <- inferExp th tenv e1
return (val,e1,cs)
(e2,val2,cs2) <- inferExp th (k,rho,(x,val1):gamma) e2
return (ALet (x,(val1,e1)) e2, val2, cs1++cs2)
App f t -> do
(f',w,csf) <- inferExp th tenv f
typ <- whnf w