lark-parser 0.2.10 2017-07-26 ✔ PY2 ✔ PY3

lark-parser on PyPI  

a modern parsing library

AuthorErez Shinan
Keywords Earley LALR parser parsing ast

Lark is a modern general-purpose parsing library for Python.

Lark focuses on simplicity and power. It lets you choose between two parsing algorithms:

Earley : Parses all context-free grammars (even ambiguous ones)! It is the default. LALR(1): Only LR grammars. Outperforms PLY and most if not all other pure-python parsing libraries. Both algorithms are written in Python and can be used interchangably with the same grammar (aside for algorithmic restrictions). See “Comparison to other parsers” for more details.

Lark can automagically build an AST from your grammar, without any more code on your part.


  • EBNF grammar with a little extra
  • Earley & LALR(1)
  • Builds an AST automagically based on the grammar
  • Automatic line & column tracking
  • Automatic token collision resolution (unless both tokens are regexps)
  • Python 2 & 3 compatible
  • Unicode fully supported