pipeless generator syntax

examples/test/misc/hello_world.das

@@ -420,6 +420,52 @@ def test_lambda_capture ( a : int ) {
 	};
 }
 
+////////////
+// generator
+
+[export]
+def test_generator ( a : int ) {
+	// passing block as argument
+	var g1 <- generator<int> (${
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	});
+	var G1 <- generator<int> capture(=a) (${
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	});
+	// simplified syntax
+	var g2 <- generator<int> {
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	};
+	var G2 <- generator<int> capture(=a) {
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	};
+	// via pipe
+	var g3 <- generator<int>() <| ${
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	};
+	var G3 <- generator<int> capture(=a) () <| ${
+		for ( x in range(1,a) ) {
+			yield x;
+		}
+		return false;
+	};
+}
+
 ///////
 // main
 

src/ast/ast_infer_type.cpp

@@ -2774,10 +2774,10 @@ namespace das {
                 return Visitor::visit(expr);
             }
             if ( expr->arguments.size()!=1 ) {
-                error("expecting generator(closure)",  "", "",
+                error("generator can only have one argument",  "", "",
                     expr->at, CompilationError::invalid_argument_count);
             } else if ( !expr->arguments[0]->rtti_isMakeBlock() ) {
-                error("expecting generator(closure)",  "", "",
+                error("expecting generator(closure), got " + string(expr->arguments[0]->__rtti) + " instead",  "", "",
                     expr->at, CompilationError::invalid_argument_type);
             } else {
                 auto mkBlock = static_pointer_cast<ExprMakeBlock>(expr->arguments[0]);

src/builtin/builtin.das.inc

@@ -371,6 +371,10 @@ static unsigned char builtin_das[] = {
 0x69,0x74,0x56,0x61,0x6c,0x75,0x65,0x0a,
 0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x6e,0x65,
+0x77,0x53,0x69,0x7a,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x72,0x65,0x73,0x69,
 0x7a,0x65,0x5f,0x6e,0x6f,0x5f,0x69,0x6e,
 0x69,0x74,0x28,0x76,0x61,0x72,0x20,0x41,
@@ -469,6 +473,10 @@ static unsigned char builtin_das[] = {
 0x6e,0x65,0x67,0x61,0x74,0x69,0x76,0x65,
 0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x76,0x61,
+0x6c,0x75,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x70,0x75,0x73,0x68,
 0x28,0x76,0x61,0x72,0x20,0x41,0x72,0x72,
 0x3a,0x61,0x72,0x72,0x61,0x79,0x3c,0x61,
@@ -516,6 +524,10 @@ static unsigned char builtin_das[] = {
 0x6e,0x27,0x74,0x20,0x62,0x65,0x20,0x63,
 0x6f,0x70,0x69,0x65,0x64,0x22,0x29,0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x76,0x61,
+0x6c,0x75,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x70,0x75,0x73,0x68,
 0x28,0x76,0x61,0x72,0x20,0x41,0x72,0x72,
 0x3a,0x61,0x72,0x72,0x61,0x79,0x3c,0x61,
@@ -562,6 +574,10 @@ static unsigned char builtin_das[] = {
 0x6e,0x27,0x74,0x20,0x62,0x65,0x20,0x63,
 0x6f,0x70,0x69,0x65,0x64,0x22,0x29,0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x76,0x61,
+0x6c,0x75,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x70,0x75,0x73,0x68,
 0x28,0x76,0x61,0x72,0x20,0x41,0x72,0x72,
 0x3a,0x61,0x72,0x72,0x61,0x79,0x3c,0x61,
@@ -612,6 +628,10 @@ static unsigned char builtin_das[] = {
 0x6e,0x27,0x74,0x20,0x62,0x65,0x20,0x63,
 0x6f,0x70,0x69,0x65,0x64,0x22,0x29,0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x76,0x61,
+0x6c,0x75,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x70,0x75,0x73,0x68,
 0x28,0x76,0x61,0x72,0x20,0x41,0x72,0x72,
 0x3a,0x61,0x72,0x72,0x61,0x79,0x3c,0x61,
@@ -662,6 +682,10 @@ static unsigned char builtin_das[] = {
 0x6e,0x27,0x74,0x20,0x62,0x65,0x20,0x63,
 0x6f,0x70,0x69,0x65,0x64,0x22,0x29,0x0a,
 0x0a,
+0x5b,0x75,0x6e,0x75,0x73,0x65,0x64,0x5f,
+0x61,0x72,0x67,0x75,0x6d,0x65,0x6e,0x74,
+0x28,0x41,0x72,0x72,0x2c,0x20,0x76,0x61,
+0x6c,0x75,0x65,0x29,0x5d,0x0a,
 0x64,0x65,0x66,0x20,0x70,0x75,0x73,0x68,
 0x28,0x76,0x61,0x72,0x20,0x41,0x72,0x72,
 0x3a,0x61,0x72,0x72,0x61,0x79,0x3c,0x61,