Index: polemy/parse.d
==================================================================
--- polemy/parse.d
+++ polemy/parse.d
@@ -324,43 +324,38 @@
 		return new App(pos, new Var(pos,"if"), cond, new Fun(thenPos,[],th), new Fun(elsePos,[],el));
 	}
 
 	AST parsePatternMatch(LexPosition pos)
 	{
-		//   case "(" pmExpr ")" CASES
+		//   case pmExpr CASES
 		//==>
 		//   let pmVar = pmExpr in (... let pmTryFirst = ... in pmTryFirst())
-		eat("(", "after case");
 		AST   pmExpr = E(0);
-		eat(")", "after case");
 		string pmVar = freshVarName();
 		string pmTryFirst = freshVarName();
 		AST   pmBody = parsePatternMatchCases(pmVar, pmTryFirst,
 			new App(pos, new Var(pos, pmTryFirst)));
 		return new Let(pos, pmVar, [], pmExpr, pmBody);
 	}
 
 	AST parsePatternMatchCases(string pmVar, string tryThisBranchVar, AST thenDoThis)
 	{
-		//    when( pat ) { cBody }
+		//    when pat: cBody
 		//==>
 		//    ... let failBranchVar = ... in
 		//    let tryThisBranchVar = fun(){ if(test){cBody}else{failBranchVar()} } in thenDoThis
 		if( tryEat("when") )
 		{
 			auto pos = currentPosition();
 			string failBranchVar = freshVarName();
 
-			eat("(", "after when");
 			auto pr = parsePattern();
-			eat(")", "after when");
-			eat("{", "after pattern");
-			AST cBody = Body();
+			eat(":", "after when pattern");
+			AST cBody = E(0);
 			AST judgement = new App(pos, new Var(pos, "if"),
 				ppTest(pmVar, pr), new Fun(pos,[],ppBind(pmVar, pr, cBody)),
 				new Var(pos, failBranchVar));
-			eat("}", "after pattern clause");
 			return parsePatternMatchCases(pmVar, failBranchVar, 
 				new Let(pos, tryThisBranchVar, [],
 					new Fun(pos,[],judgement), thenDoThis)
 			);
 		}
@@ -661,20 +656,20 @@
 
 unittest
 {
 	assert_nothrow(parseString(`
 		case( 1 )
-			when(x){1}
+			when(x): 1
 	`));
 	assert_nothrow(parseString(`
-		case( 1 )
-			when({aaaa:_}){1}
+		case 1
+			when {aaaa:_}: 1
 	`));
 	assert_nothrow(parseString(`
-		case( 1 )
-			when({aaaa:@value(x)}){1}
-			when({aaaa:{bbb:_}, ccc:123}){1}
+		case 1
+			when {aaaa:@value(x)}: 1
+			when {aaaa:{bbb:_}, ccc:123}: 1
 	`));
 }
 
 unittest
 {

Index: sample/ast.pmy
==================================================================
--- sample/ast.pmy
+++ sample/ast.pmy
@@ -1,27 +1,27 @@
 def reverse(lst, acc)
 {
 	case(lst)
-		when( {car:a, cdr: d} ) { reverse(d, {car:a, cdr:acc}) }
-		when( {} ) { acc }
+		when {car:a, cdr: d}:  reverse(d, {car:a, cdr:acc})
+		when {}:   acc
 };
 
 @macro reverseArgs(e) {@value(
 	var ev = @macro(e);
 	case(ev)
-		when( {is:"App", fun:f, args:a} )
-		{
+		when {is:"App", fun:f, args:a}:
+		(
 			ev {args: reverse(a, {})}
-		}
-		when( _ ) 
-		{
+		)
+		when _ :
+		(
 			ev
-		}
+		)
 )};
 
 def main()
 {
 	print( reverseArgs(1 + 2) );
 	print( reverseArgs(1 - 2) );
 };
 
 main()