(Previously named 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.
```rust extern crate combine; use combine::{many, Parser}; use combine::char::letter;
let result = many(letter()).parse("hello world"); asserteq!(result, Ok(("hello".tostring(), " world"))); ```
Larger examples can be found in the examples and benches folders.
A parser combinator 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. Thanks to the modularity that parser combinators gives it is possible to define parsers for a wide range of tasks without needing to implement the low level plumbing while still having the full power of Rust when you need it.
The library is almost stable but a few parts of the internals may still change before 1.0. After that the library will adhere to semantic versioning.
If you end up trying it I welcome any feedback from your experience with it. I am usually reachable within a dat by opening an issue or sending an email. I am also testing gitter for smaller questions.
There is an additional crate which has parsers to lex and parse programming languages in combine-language.
You can find older versions of combine (parser-combinators) here.
The easiest way to contribute is to just open an issue about any problems you encounter using combine but if you are intersted in adding something to the library here is a list of some of the easier things to work on to get started.
Here is a list containing most of the breaking changes in older versions of combine (parser-combinators).
&[T] streams has had the Item type changed from &T to T and requires a T: Copy bound.Error::Unexpected holds an Info<T, R> instead of just a T to make it consitent with the other variants.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).ParseResult from primitives you should no longer specify the item type of the stream.Stream::uncons changed its signature to allow it to return errors. Return Error::end_of_input() instead of () if you implemented Stream.Parser::parse_lazy, should not break anything but I can't say for certain.any_char -> any, uncons_char -> unconsPositioner 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.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.Error which can hold any kind of ::std::error::Errorchoice_vec and choice_slice is replaced by just choicefrom_iter functionIf you have trouble updating to a newer version feel free to open an issue and I can take a look.