parser-combinators

An implementation of parser combinators for Rust, inspired by the Haskell library Parsec. As in Parsec the parsers are LL(1) by default but they can opt-in to arbitrary lookahed using the try combinator.

A parser combinators is, broadly speaking, a function which takes several parsers as arguments and returns a new parser, created by combining those parsers. For instance, the many parser takes one parser, p, as input and returns a new parser which applies p zero or more times.

The library is mostly stable but a few parts of the internals may still change. If you end up trying it I welcome any feedback from your experience with it.

##Example

extern crate parser_combinators;
use parser_combinators::{many, Parser};
use parser_combinators::char::letter;

let result = many(letter()).parse("hello world");
assert_eq!(result, Ok(("hello".to_string(), " world")));

Links

Documentation and examples

crates.io

Extra

There is an additional crate which has parsers to lex and parse programming languages in parser-combinators-language.

Breaking changes

Here is a list containing most of the breaking changes in older versions of parser-combinators.

0.7.0

• Stream::uncons changed its signature to allow it to return errors. Return Error::end_of_input() instead of () if you implemented Stream.

0.6.0

• Addition of Parser::parse_lazy, should not break anything but I can't say for certain.

0.5.0

• any_char -> any, uncons_char -> uncons
• Introduction of the Positioner trait which needs to be implemented on an custom token types.
• satisfy is moved to the combinators module and made generic, might cause type inference issues.

0.4.0

• any_char is no longer a free function but returns a parser when called as all parser functions (and its called any after 0.5.0)
• Cow is replaced by Info in the error messages.

0.3.2 / 0.3.0

• Added variant to Error which can hold any kind of ::std::error::Error
• choice_vec and choice_slice is replaced by just choice

0.2.6

• Iterators cannot directly be used as streams but must be wrapped using from_iter function

If you have trouble updating to a newer version feel free to open an issue and I can take a look.