case 1:
if (iter != null) return new FCallOneArgBlockNode(union(operation, args), name, args, (IterNode) iter);
return new FCallOneArgNode(union(operation, args), name, args);
case 2:
if (iter != null) return new FCallTwoArgBlockNode(union(operation, args), name, args, (IterNode) iter);
return new FCallTwoArgNode(union(operation, args), name, args);
case 3:
if (iter != null) return new FCallThreeArgBlockNode(union(operation, args), name, args, (IterNode) iter);