From 3506e1282ae8ce56bce4832a8ca5935c06bc3a6d Mon Sep 17 00:00:00 2001
From: darkf <lw9k123@gmail.com>
Date: Sat, 19 Oct 2013 01:56:14 -0700
Subject: [PATCH] add multiple pattern arguments in parser

---
 ast.hs    |  2 +-
 parser.hs | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/ast.hs b/ast.hs
index cf216ea..57d9381 100644
--- a/ast.hs
+++ b/ast.hs
@@ -3,7 +3,7 @@ module AST where
 data AST = Add AST AST
 		 | Mul AST AST
 		 | Block [AST]
-		 | FunDef String (Pattern, AST)
+		 | FunDef String ([Pattern], AST)
 		 | Def String AST
 		 | Var String
 		 | Lambda [(Pattern, [AST])]
diff --git a/parser.hs b/parser.hs
index 002573d..8664a6a 100644
--- a/parser.hs
+++ b/parser.hs
@@ -43,18 +43,24 @@ pattern = option UnitP $
 	        fmap VarP identifier
 	    <|> fmap IntP integer
 
+patterns = sepBy pattern (symbol ",")
+
 funDef = do
 	name <- identifier
 	symbol "("
-	pat <- pattern
+	pats <- patterns
+	let pats' = if pats == [] then [UnitP] else pats -- at least Unit
 	symbol ")"
 	symbol "->"
 	lst <- exprparser
-	return $ rewriteFun (FunDef name (pat, lst))
+	return $ rewriteFun (FunDef name (pats, lst))
 
 -- curry FunDef to a definition of lambdas
-rewriteFun (FunDef name (pattern, body)) =
-	Def name $ Lambda [(pattern, [body])]
+rewriteFun (FunDef name (patterns, body)) =
+	Def name lam
+	where
+		-- curry it
+		lam = foldr (\pat lam -> Lambda [(pat, [lam])]) body patterns
 
 call = do
 	name <- identifier