[posborne]

I am the author of one such library for the problem of writing parsers (particularly for binary protocols). The declaration of the protocol structures are separate from anything involving I/O. Not trying to push it too hard but it is one approach: https://github.com/digidotcom/python-suitcase

There is also Construct which has a different syntax but is similar in many ways: http://construct.readthedocs.io/en/latest/index.html

Both suitcase/construct are definitely better suited for parsing binary protocols -- In my line of work, that limitation hasn't been a deal breaker. With suitcase, at least, I haven't done much work to optimize performance (mostly because if I cared, I wouldn't be using Python).

[JoshTriplett]

Both of those look great; thanks for the pointer to them!