lalrpop

LR(1) parser generator for Rust

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LALRPOP

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LALRPOP is a Rust parser generator framework with usability as its
primary goal. You should be able to write compact, DRY, readable
grammars. To this end, LALRPOP offers a number of nifty features:

  1. Nice error messages in case parser constructor fails.
  2. Macros that let you extract common parts of your grammar. This
    means you can go beyond simple repetition like Id* and define
    things like Comma<Id> for a comma-separated list of identifiers.
  3. Macros can also create subsets, so that you easily do something
    like Expr<"all"> to represent the full range of expressions, but
    Expr<"if"> to represent the subset of expressions that can appear
    in an if expression.
  4. Builtin support for operators like * and ?.
  5. Compact defaults so that you can avoid writing action code much of the
    time.
  6. Type inference so you can often omit the types of nonterminals.

Despite its name, LALRPOP in fact uses LR(1) by default (though you
can opt for LALR(1)), and really I hope to eventually move to
something general that can handle all CFGs (like GLL, GLR, LL(*),
etc).

Documentation

The LALRPOP book covers all things LALRPOP -- or at least it intends
to! Here are some tips:

  • The tutorial covers the basics of setting up a LALRPOP parser.
  • For the impatient, you may prefer the quick start guide section, which describes
    how to add LALRPOP to your Cargo.toml.
  • The advanced setup chapter shows how to configure other aspects of LALRPOP's
    preprocessing.
  • If you have any questions join our gitter lobby.

Example Uses

  • LALRPOP is itself implemented in LALRPOP.
  • Gluon is a statically typed functional programming language.
  • Gleam is a statically typed functional programming language for the Erlang VM.
  • RustPython is Python 3.5+ rewritten in Rust
  • Solang is Ethereum Solidity rewritten in Rust

Contributing

You really should read CONTRIBUTING.md if you intend to change LALRPOP's own grammar.

Main metrics

Overview
Name With Ownerlalrpop/lalrpop
Primary LanguageRust
Program languageRust (Language Count: 3)
Platform
License:Apache License 2.0
所有者活动
Created At2015-06-12 19:41:37
Pushed At2025-07-16 05:47:50
Last Commit At2025-07-15 22:47:20
Release Count38
Last Release Name0.22.2 (Posted on 2025-05-22 14:49:44)
First Release Name0.12.4 (Posted on )
用户参与
Stargazers Count3.3k
Watchers Count32
Fork Count300
Commits Count1.6k
Has Issues Enabled
Issues Count461
Issue Open Count145
Pull Requests Count510
Pull Requests Open Count18
Pull Requests Close Count62
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