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lab16: impl

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Yura
2026-04-23 01:53:08 -07:00
parent 95bb649249
commit 574225a0f3
1 changed files with 23 additions and 4 deletions
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27
lab16/stlc.hs
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@@ -51,10 +51,19 @@ typecheck e@(EIf e1 e2 e3) env =
t2 = typecheck e2 env t2 = typecheck e2 env
t3 = typecheck e3 env t3 = typecheck e3 env
in if t1 == TBool && t2 == t3 then t2 else typecheckFail e in if t1 == TBool && t2 == t3 then t2 else typecheckFail e
typecheck e@(EIsZero e1) env = error "TBD" typecheck e@(EIsZero e1) env = case typecheck e1 env of
typecheck e@(EVar x) env = error "TBD" TInt -> TBool
typecheck e@(ELambda x tin e') env = error "TBD" _ -> typecheckFail e
typecheck e@(EApp e1 e2) env = error "TBD" typecheck e@(EVar x) env = case Map.lookup x env of
Just t -> t
Nothing -> typecheckFail e
typecheck e@(ELambda x tin e') env =
let env' = Map.insert x tin env
in TFun tin (typecheck e' env')
typecheck e@(EApp e1 e2) env =
let t1@(TFun tin tout) = typecheck e1 env
t2 = typecheck e2 env
in if t2 == tin then tout else typecheckFail e
--Some sample cases --Some sample cases
@@ -67,3 +76,13 @@ test5 = typecheck (EApp (ELambda "x" TInt (EIf (EIsZero (EVar "x")) (ESucc zero)
bad1 = typecheck (ESucc EFalse) Map.empty bad1 = typecheck (ESucc EFalse) Map.empty
bad2 = typecheck (EApp (ELambda "x" TInt (EIsZero (EVar "x"))) ETrue) Map.empty bad2 = typecheck (EApp (ELambda "x" TInt (EIsZero (EVar "x"))) ETrue) Map.empty
-- main
main = do
print test1
print test2
print test3
print test4
print test5
print bad1
print bad2