combine

(Previously 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 combine;
use combine::{many, Parser};
use combine::char::letter;

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

More examples can be found in the examples and benches folders.

Links

Documentation and examples

crates.io

Extra

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

Breaking changes

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

1.0.0-beta.2

• Info<T> and Error<T> has had their signatures changed to Info<T, R> and Error<T, R>. Info has a new variant which is specified by R and defines the type for range errors. ParseError<T: Positioner> has been changed to ParseError<S: Stream> (S is the stream type of the parser).
• If you were using ParseResult from primitives you should no longer specify the item type of the stream.

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.