If you study regex manuals/usage well, you will learn that it was invented for the kind of work you want to do.

Take some time off your project (if time allows) and read up on regex. Search google or try this article for example.

With regexp, its even possible to accomplish your "AI" analysis in one statement using conditional operation

Consider this pseudocode

bool boolvar = (one of your "positive feedback" substrings is found by regexp)?true:false;