From a9134688a2132c8f9abfff206f6e30614bb9aeff Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom.smeding@gmail.com>
Date: Thu, 23 Jul 2020 20:16:39 +0200
Subject: WIP lambdas

---
 parser/CC/Parser.hs | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

(limited to 'parser/CC')

diff --git a/parser/CC/Parser.hs b/parser/CC/Parser.hs
index d6c2239..d9e5b40 100644
--- a/parser/CC/Parser.hs
+++ b/parser/CC/Parser.hs
@@ -54,9 +54,31 @@ pTypeAtom :: Parser Type
 pTypeAtom = (wordToken "Int" >> return TInt) <|> between (token "(") (token ")") pType
 
 pExpr :: Parser Expr
-pExpr = lab "expression" $ do
-    atoms <- many1 pExprAtom
-    return (foldl1 (\a b -> Call (mergeRange (range a) (range b)) a b) atoms)
+pExpr = label (pCall <|> pLam) "expression"
+  where
+    pCall = do
+        atoms <- many1 pExprAtom
+        annot <- optionMaybe (do symbol "::"
+                                 p1 <- getPosition
+                                 ty <- pType
+                                 p2 <- getPosition
+                                 return (ty, SourceRange p1 p2))
+        let call = foldl1 (\a b -> Call (mergeRange (range a) (range b)) a b) atoms
+        case annot of
+            Just (ty, sr) -> return (Annot (mergeRange (range call) sr) call ty)
+            Nothing -> return call
+
+    pLam = do
+        p1 <- try $ do
+            whitespace
+            p <- getPosition
+            void (char '\\')
+            return p
+        names <- many1 pName
+        symbol "->"
+        body <- pExpr
+        p2 <- getPosition
+        return (Lam (SourceRange p1 p2) names body)
 
 pExprAtom :: Parser Expr
 pExprAtom =
@@ -106,9 +128,6 @@ emptyLines = (try (whitespace >> newline) >> emptyLines) <|> try (whitespace >>
 whitespace :: Parser ()
 whitespace = void (many (char ' '))
 
-lab :: String -> Parser a -> Parser a
-lab = flip label
-
 getPosition :: Parser SourcePos
 getPosition = do
     pos <- Text.Parsec.getPosition
-- 
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