shithub: MicroHs

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Add :: in expressions.

--- a/src/MicroHs/Desugar.hs

+++ b/src/MicroHs/Desugar.hs

@@ -166,6 +166,7 @@

               dsExpr (EIf c (ECompr e stmts) (EList []))

             SLet ds ->

               dsExpr (ELet ds (ECompr e stmts))

+    ESign e _ -> dsExpr e

     EAt _ _ -> undefined

     EUVar _ -> undefined

     ECon c ->

--- a/src/MicroHs/Expr.hs

+++ b/src/MicroHs/Expr.hs

@@ -73,6 +73,7 @@

   | ESectR Ident Expr

   | EIf Expr Expr Expr

   | ECompr Expr [EStmt]

+  | ESign Expr EType

   | EAt Ident Expr  -- only in patterns

   -- Only while type checking

   | EUVar Int

@@ -228,6 +229,7 @@

     ESectR i e -> i : allVarsExpr e

     EIf e1 e2 e3 -> allVarsExpr e1 ++ allVarsExpr e2 ++ allVarsExpr e3

     ECompr e ss -> allVarsExpr e ++ concatMap allVarsStmt ss

+    ESign e _ -> allVarsExpr e

     EAt i e -> i : allVarsExpr e

     EUVar _ -> []

     ECon c -> [conIdent c]

@@ -317,6 +319,7 @@

     ESectR i e -> "(" ++ showIdent i ++ " " ++ showExpr e ++ ")"

     EIf e1 e2 e3 -> "if " ++ showExpr e1 ++ " then " ++ showExpr e2 ++ " else " ++ showExpr e3

     ECompr _ _ -> "ECompr"

+    ESign e t -> showExpr e ++ " :: " ++ showEType t

     EAt i e -> showIdent i ++ "@" ++ showExpr e

     EUVar i -> "a" ++ showInt i

     ECon c -> showCon c

--- a/src/MicroHs/Parse.hs

+++ b/src/MicroHs/Parse.hs

@@ -405,7 +405,10 @@

 pExprApp = P.do

   f <- pAExpr

   as <- emany pAExpr

-  pure $ foldl EApp f as

+  mt <- optional (pSymbol "::" *> pType)

+  let

+    r = foldl EApp f as

+  pure $ maybe r (ESign r) mt

 pLam :: P Expr

 pLam = ELam <$> (pSymbol "\\" *> esome pAPat) <*> (pSymbol "->" *> pExpr)

--- a/src/MicroHs/TypeCheck.hs

+++ b/src/MicroHs/TypeCheck.hs

@@ -757,6 +757,11 @@

         tr = tApp tList ta

       munify (getSLocExpr ae) mt tr

       T.return (ECompr ea rss, tr)

+    ESign e t -> T.do

+      (tt, _) <- withTypeTable $ tcType (Just kType) t

+      (ee, _) <- tcExpr (Just tt) e

+      munify (getSLocExpr ae) mt tt

+      T.return (ESign ee tt, tt)

     EAt i e -> T.do

       (ee, t) <- tcExpr mt e

       (_, ti) <- tLookupInst "impossible!" i

-- 

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