This is a simple example of using Pygments along with a simple state machine to facilitate code review. The basic idea is to use the available lexers of Pygments to tokenize source code and then build little targeted "parsers" which recognize desirable code patterns.
The crotch module is mostly just a general purpose state machine modified to handle basic file operations and (type,value) tuples returned by Pygments lexers. To use this class you implement handlers (representing states), which are basically callable functions which expect two arguments (token type, token value) and return the name of the next state (handler) to traverse to. You add these handlers to the state machine with the add_state() method, and also specify the start state and every "end state", which should result in a traceback report.
Examples are provided along with the core module.
If you need more complex queries I suggest to take a look at Joern that provides a real parser (not just a lexer) and a sophisticated query language for your searches. The downside is that it only handles C out-of-the-box, but with some effort you can create your own parser for it.