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# Features
## Main Features
- Earley parser, capable of parsing any context-free grammar
- Implements SPPF, for efficient parsing and storing of ambiguous grammars.
- LALR(1) parser, limited in power of expression, but very efficient in space and performance (O(n)).
- Implements a parse-aware lexer that provides a better power of expression than traditional LALR implementations (such as ply).
- EBNF-inspired grammar, with extra features (See: [Grammar Reference](grammar.md))
- Builds a parse-tree (AST) automagically based on the grammar
- Stand-alone parser generator - create a small independent parser to embed in your project. ([read more](tools.html#stand-alone-parser))
- Flexible error handling by using an interactive parser interface (LALR only)
- Automatic line & column tracking (for both tokens and matched rules)
- Automatic terminal collision resolution
- Warns on regex collisions using the optional `interegular` library. ([read more](how_to_use.html#regex-collisions))
- Grammar composition - Import terminals and rules from other grammars (see [example](https://github.com/lark-parser/lark/tree/master/examples/composition)).
- Standard library of terminals (strings, numbers, names, etc.)
- Unicode fully supported
- Extensive test suite
- Type annotations (MyPy support)
- Pure-Python implementation
[Read more about the parsers](parsers.md)
## Extra features
- Support for external regex module ([see here](classes.html#using-unicode-character-classes-with-regex))
- Import grammars from Nearley.js ([read more](tools.html#importing-grammars-from-nearleyjs))
- CYK parser
- Visualize your parse trees as dot or png files ([see_example](https://github.com/lark-parser/lark/blob/master/examples/fruitflies.py))
- Automatic reconstruction of input from parse-tree (see [example](https://github.com/lark-parser/lark/blob/master/examples/advanced/reconstruct_json.py) and [another example](https://github.com/lark-parser/lark/blob/master/examples/advanced/reconstruct_python.py))
- Use Lark grammars in [Julia](https://github.com/jamesrhester/Lerche.jl) and [Javascript](https://github.com/lark-parser/Lark.js).
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