https://github.com/brandonbloom/ambiparse

Parsing with "disambiguation filters" in Clojure
https://github.com/brandonbloom/ambiparse

Last synced: 2 months ago
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Parsing with "disambiguation filters" in Clojure

• Host: GitHub
• URL: https://github.com/brandonbloom/ambiparse
• Owner: brandonbloom
• License: epl-1.0
• Created: 2014-11-09T21:02:16.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2017-01-11T21:03:07.000Z (almost 8 years ago)
• Last Synced: 2024-11-01T17:42:29.553Z (2 months ago)
• Language: Clojure
• Homepage:
• Size: 165 KB
• Stars: 22
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Ambiparse

Ambiparse is an embedded Clojure DSL that provides parsing for very rich

grammars including ambiguity and adaptability.

## Overview

Ambiparse is capable of parsing any context free language, including

both left-and-right recursive grammars, as well as ambiguous grammars. The

parser is capable of returning a parse tree for ambiguous parses. Furthermore,

grammar productions can be modified during parsing, allowing langauges to

express arbitrary syntax extensions. This means that the parser is actually

capable of parsing many context-sensitive grammars as well.

Ambiguity can be reduced or eliminated from grammars with "disambiguation

filters", which allow for declarative operator associativity and precedence, as

well as filtering by arbitrary predicates.

Being an embedded DSL enables inline semantic actions. Semantic actions can

rewrite _concrete_ syntax trees at parse time in to arbitrary _abstract_

syntax trees, or even perform simple interpretation.

To the best of my knowledge, this confluence of features is novel.

## Usage

Ambiparse is still very early days, so no release has been published, and a

metric ton of documentation is yet to be written. This project was built to

serve a higher-priority project, so it may be a while, if ever, that this

changes.

See the [calculator][1] and [edn parser][2] test code for examples.

The public API is provided by [ambiparse.clj][8] exclusively.

Note that performance is expectedly awful. This too may never change.

## References

- [GLL Parsing][5] by Scott and Johnstone.

- [Disambiguation Filters for Scannerless Generalized LR Parsers][6]

  by M.G.J. van den Brand et al.

- [Faster, Practical GLL Parsing][7] by Afroozeh and Izmaylova.

- [Recursive Adaptable Grammars][9] by John Shutt.

## Acknowledgements

Thanks to Mark Engelberg for [Instaparse][3], an excellent library that you

probably should use over Ambiparse, [his talk][4] which is an excellent

explanation of the GLL algorithm, as well as several excellent discussions

on the finer points of the algorithm's implementation.

## License

Copyright © 2016 Brandon Bloom

Distributed under the Eclipse Public License version 1.0.

[1]: ./test/ambiparse/calc_test.clj

[2]: ./test/ambiparse/edn_test.clj

[3]: https://github.com/Engelberg/instaparse

[4]: https://www.youtube.com/watch?v=b2AUW6psVcE

[5]: http://dotat.at/tmp/gll.pdf

[6]: http://www.st.ewi.tudelft.nl/~eelco/papers/BSVV02.pdf

[7]: http://oai.cwi.nl/oai/asset/24026/24026B.pdf

[8]: ./src/ambiparse.clj

[9]: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.45.2424&rep=rep1&type=pdf