Why don't you tell us exactly what you want to do, what you have, and what limitations there are. I still don't understand exactly what you are doing, or where you need help - and I'm probably not the only one.
folks are delighted to help, but you have to make it easy for them. so far, this thread has progressed like this:
1) you asked a question
2) you were given a valid way to do it
3) you said "I need another way"
4) you were asked why that way wouldn't work
5) you said "I'm trying to do something else entirely than what I originally asked"
at least, that's how it reads to me. Many folks here at this point are going to give up on reading this thread because it's too much work, and too much effort has been wasted.
The best way to get help is to clearly explain what you are doing, and where you are stuck. From you last post, I gather you are trying to parse a string that contains a mathematical expression. Is that correct? and if so, what EXACTLY is the issue you are having - tokenizing it, evaluating it, reading the string in from some input source, or something else?
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors