nom-derive

Overview

nom-derive is a custom derive attribute, to derive nom parsers automatically from the structure definition.

This is only test code for now. Feedback welcome !

`#[derive(Nom)]`

This crate exposes a single custom-derive macro Nom which implements parse for the struct it is applied to.

The goal of this project is that:

derive(Nom) should be enough for you to derive nom parsers for simple structures easily, without having to write it manually
it allows overriding any parsing method by your own
it allows using generated parsing functions along with handwritten parsers and combining them without efforts

Usage

Add to your Cargo.toml file::

 nom-derive = "0.1"
 nom = "4.2"

Add #[derive(Nom)] to the structure(s) you want.

See the tests directory for examples.

Example

This implementation:

#[macro_use]
extern crate nom_derive;

#[macro_use]
extern crate nom;

use nom::*;

#[derive(Nom)]
struct SimpleStruct {
    pub a: u32,
    b: u64,
}

Allows you to generate the nom parser for SimpleStruct automatically. The function is called SimpleStruct::parse.

The generated code is equivalent to::

impl SimpleStruct {
    fn parse(i: &[u8]) -> IResult<&[u8],SimpleStruct> {
        do_parse!(
            i,
            a: be_u32 >>
            b: be_u64 >>
            ( SimpleStruct{ a,b } )
        )
    }
}

Limitations

Debugging macros is hard. Debugging macros generated by a custom derive is a nightmare. The expand cargo subcommand can help !

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

nom-derive 0.1.0