Parsy is an easy and elegant way to parse text in Python by combining small
parsers into complex, larger parsers. If it means anything to you, it's a
monadic parser combinator library for LL(infinity) grammars in the spirit of
Parsec, Parsnip, and Parsimmon. But don't worry, it has really good
documentation and it doesn't say things like that!

For a good example of the kind of clear, declarative code you can create using
parsy, see the SQL SELECT statement example or JSON parser.

The project:
- has zero dependencies outside stdlib.
- is highly mature and stable, with few-to-none backwards incompatibilities over
  the past 10 years.
- is essentially complete, with no rewrites planned. Widely useful improvements
  that don't break compatibility will still be considered, however.
- is implemented in a single module with less than 800LOC, which you could
  vendor easily if required.