I searched all over the internet for a good implementation in converting not numbers expressions but variable expressions from infix notation into prefix and postfix. All the searches I did weren't successful. Basically I want to see if there is any implementation yet in PHP so I could modify it to support more operators not only the (-,*,+,=).
For example convert:
a+b/c*(p/c)
While keeping the variable names, and not having to enter numbers to evaluate them.