How do I find out where in the distribution or source code a particular function or feature is implemented? I’m specifically at this point interested in the regexp stuff, but I’d like to know in general. Thanks.

This is the new regexp implementation for Racket CS: https://github.com/racket/racket/tree/master/racket/src/regexp The old one is in C, I believe.

If the feature you are looking for is a primitive then go http://github.com/racket/racket\|github.com/racket/racket and use Github search to find the definition. For functions/structures defined in Racket you can use DrRacket or racket-mode to find the definition.

Thanks!