Been Googling around without finding much at all, so does anyone know of a class or library that helps you parse any sort of language, like a Domain Specific Language (I'm creating one, so I'm flexible in what the syntax and format can be) into either PHP code or some helpful struct or a class hiearchy or ... ? Anything goes at this point. :)

I want to experiment with parsing text files into tokens, building up a small grammar and syntax library to express things like Business Natural Languages.