First of all, wherever you got the syntax for that, its over a year old and is invalid. Secondly, the error means what it says, it didnt find () around your conditions. I suggest not looking in the outdated macro forum for macros, theres plenty in the non-outdated forum
The correct syntax would be something more like /if (!${p0.Length}) {
However, I dont know what you're trying to do or what p0 is, etc., so I would stick to my first paragraph... dont look in the outdated macro forum