I recently had the task of learning how to implement our internal company PHP coding standards documents which exist only as a set of JIRA pages into something that could be integrated into the subversion pre-commit checking phase so that not only does code have to be syntax error free, it now also has to adhere to the coding standards. I remembered reading about PHP_CodeSniffer (PCS) and volunteered to "have a look" and see if I could implement one of the more simpler standards, our variable naming convention, as a starter exercise. Well, after the mandatory head-banging and spike in coffee consumption that accompanies learning new stuff, I became very impressed by the way that PCS actually does what it does. It builds upon the token_get_all() function and creates not just an array of tokens and there positions but it also figures out (I read the source for half an hour!) which bits of code are contained within other bits of code; in other words the context within which...
To know one thing, you must know the opposite. -- Henry Moore