@@ -0,0 +1,312 @@
+import java.util.List;%0A%0Apublic class ErrorFun extends BuiltinFun %7B%0A%0A%09public ErrorFun() %7B%0A%09%09super(%22error%22, -1);//ignore param's count%0A%09%7D%0A%0A%09@Override%0A%09public Value apply(List%3CValue%3E args, Position pos) %7B%0A%09%09System.err.println(pos + %22 %22 + U.join(%22 %22, args));%0A%09%09System.exit(1);%0A%09%09return Value.VOID;//never touch%0A%09%7D%0A%7D%0A

add error()