Thread:Project:Support desk/calling functions in a hook extension

I'm trying to write a hook extension. I have .php file which has: My issue is I need to call another function eg form within fnAddImages but when I try to I get the message: Fatal error: Call to undefined function form;

How to I call other functions in the class besides for the 'hooked' function? Am I missing something about understanding hooks? I need to output other data (form submission) besides for just returning true on the hooked function. I thought I would do this by calling other functions within the hook. Is there a better way to do this? Thanks, I'm really stuck on this.