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norswap/autumn

A Java parser combinator library written with an unmatched feature set.
Source code at GitHub https://github.com/norswap/autumn
norswap/autumn.json
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  "createdAt": "2016-11-22T15:12:16Z",
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  "description": "A Java parser combinator library written with an unmatched feature set.",
  "fullName": "norswap/autumn",
  "homepage": "",
  "language": "Java",
  "name": "autumn",
  "pushedAt": "2021-10-30T13:37:02Z",
  "stargazersCount": 131,
  "topics": [
    "grammar",
    "grammars",
    "parse-trees",
    "parser",
    "parser-combinator",
    "parser-combinators",
    "parser-framework",
    "parser-library",
    "parsers",
    "parsing",
    "parsing-combinators",
    "parsing-expression-grammar"
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  "updatedAt": "2025-11-08T04:17:23Z",
  "url": "https://github.com/norswap/autumn"
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Autumn

Section titled “Autumn”
  • [Install]!(/doc/INSTALL.md)
  • [Javadoc] (updates daily) / [Mirror] (might need loading)
  • [User Guide]!(/doc/README.md)

[Javadoc] !: https://javadoc.io/doc/com.norswap/autumn/ [Mirror] !: https://jitpack.io/com/github/norswap/autumn/-SNAPSHOT/javadoc/

Autumn is a Java (8+) parser combinator library written with an unmatched feature set:

  • Bundles pre-defined parsers and combinators for most common use cases
  • Write your own parsers with regular Java code
  • Support for both scannerless parsing and a separate lexing/tokenization step
  • Support for parsing both text strings and lists of objects
  • Associativity support for operators
  • Left-recursion support
  • Context-sensitive parsing (exclusive !!)
  • Reasonably fast (5x slower than (the very fast) ANTLR)
  • Thoroughly documented
  • Small & clean codebase

Examples:

  • [JSON Grammar]!(/examples/norswap/lang/json/JSON.java)
  • [Java Grammar]!(/examples/norswap/lang/java/JavaGrammar.java)

The latest version of this document is available online at https://github.com/norswap/autumn/blob/master/README.md

Versioning

Section titled “Versioning”

Versions are M.m.p

  • Major (M) is incremented when significant changes are made to the library. It might take non-trivial time to migrate.
  • Minor (m) is incremented when new features are added, or existing features are modified. The main contract here is that migration should be quick, and a clear migration path exists.
  • Patch (p) is incremented for hotfixes, or tiny / quality-of-life improvements. Patch never introduce breaking changes, excepted under the guise of bug-fixes.

Legacy

Section titled “Legacy”

If you were looking for older Autumn releases (such as those described in one of my [papers]), see the [autumn_archive repository][archive].

If you were looking for the Whimsy compiler framework, see [here][whimsy]. The Uranium semantic analysis library lives on [in this repository][uranium].

[papers] !: https://norswap.com/publications/ [archive] !: https://github.com/ncellar/autumn_archive [whimsy] !: https://github.com/ncellar/whimsy [uranium] !: https://github.com/norswap/uranium