Lark is a parsing toolkit for Python, built with a focus on ergonomics, performance and modularity.
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README.md Added a short README file 2017-02-05 13:24:08 +02:00

README.md

Lark - a modern pure-Python parsing library

Lark is a modern general-purpose Python parsing library, that focuses on simplicity and power.

Lark accepts grammars as EBNF and lets you choose between two parsing algorithms:

  • Earley : Parses all context-free grammars (even ambiguous ones)!
  • LALR(1): Only LR grammars. Outperforms PLY and most if not all other pure-python parsing libraries.

Both algorithms are pure-python implementations and can be used interchangably (aside for algorithmic restrictions).

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

Lark does things a little differently

  1. Separates code from grammar: The result is parsers that are cleaner and easier to read & work with.

  2. Automatically builds a tree (AST): Trees are always simpler to work with than state-machines. (But if you want to provide a callback for efficiency reasons, Lark lets you do that too)

  3. Follows Python's Idioms: Beautiful is better than ugly. Readability counts.

Features

  • EBNF grammar with a little extra
  • Earley & LALR(1)
  • Builds an AST automagically based on the grammar
  • Python 2 & 3 compatible
  • Supports unicode

License

Lark uses the GPL3 license.

Contact

If you have any questions or want to contribute, please email me at erezshin at gmail com.