logos

Logos

Create ridiculously fast Lexers.

Logos has two goals:

• To make it easy to create a Lexer, so you can focus on more complex problems.
• To make the generated Lexer faster than anything you'd write by hand.

To achieve those, Logos:

• Combines all token definitions into a single deterministic state machine.
• Optimizes branches into lookup tables or jump tables.
• Prevents backtracking inside token definitions.
• Unwinds loops, and batches reads to minimize bounds checking.
• Does all of that heavy lifting at compile time.

Example

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For more examples and documentation, please refer to the Logos handbook or the crate documentation.

How fast?

Ridiculously fast!

test identifiers                       ... bench:         647 ns/iter (+/- 27) = 1204 MB/s
test keywords_operators_and_punctators ... bench:       2,054 ns/iter (+/- 78) = 1037 MB/s
test strings                           ... bench:         553 ns/iter (+/- 34) = 1575 MB/s

Acknowledgements

• Pedrors for the Logos logo.

Thank you

Logos is very much a labor of love. If you find it useful, consider getting me some coffee. ☕

If you'd like to contribute to Logos, then consider reading the Contributing guide.

Contributing

Logos welcome any kind of contribution: bug reports, suggestions, or new features!

Please use the issues or pull requests tabs, when appropriate.

To release a new version, follow the RELEASE-PROCESS

License

This code is distributed under the terms of both the MIT license and the Apache License (Version 2.0), choose whatever works for you.

See LICENSE-APACHE and LICENSE-MIT for details.