Top 3 parsing-engine open source projects

Lark is a parsing toolkit for Python, built with a focus on ergonomics, performance and modularity.

The COMPLETE (!) source code of the Sc2gears universe (Sc2gears app + Sc2gears Database + web-based parsing engine - bundled in an Eclipse project).

The Greynir NLP parser for Icelandic, packaged for PyPI