COSMIC NOM

Is a collection of utilities for making using the great nom parser combinator easier to use.

THE COSMIC INITIATIVE

cosmic-nom is part of The Cosmic Initiative a WebAssembly orchestration framework--although you can use it for any project you want.

A DERIVATIVE OF DERIVATIVE WORKS

cosmic-nom synthesizes the utilities of two other derivatives of nom:

• nom-supreme A collection of excellent utilities for nom (which cosmic-nom uses for improved error handling)
• nom_locate A special input type for nom to locate tokens (which cosmic-nom uses to locate error spans in the parsed content)

COSMIC NOMS CONTRIBUTIONS

IMPLEMENTATION

To use cosmic-nom you must accept an input implementing trait cosmic_nom::Span and return a result of type cosmic_nom::Res:

pub fn name<I:Span>( input:I ) -> Res<I,I> {
  alpha(input)
}

SPAN

Since It is hard to compose a combinator if your input type doesn't implement all of the traits used in every condition: InputLength, InputTakeAtPosition, AsBytes, etc... So cosmic-nom provides a single trait that also supports location captures via nom_locate and seems to work with every combinator in the complete package (not tested on streaming).

pub trait Span:
    Clone
    + ToString
    + AsBytes
    + Slice<Range<usize>>
    + Slice<RangeTo<usize>>
    + Slice<RangeFrom<usize>>
    + InputLength
    + Offset
    + InputTake
    + InputIter<Item = char>
    + InputTakeAtPosition<Item = char>
    + Compare<&'static str>
    + FindSubstring<&'static str>
    + core::fmt::Debug

To create a span call cosmic_nom::new_span("scott williams")

name(new_span("scott williams"));

RESULT

use result to transform your Res into a regular Result<O,E>

let name: I = result(name(new_span("scott williams")))?;

LOG

and you can wrap your result in a log() which will output to stdout if an error occurs:

let name: I = log(result(name(new_span("scott williams"))))?;

IMPORTANT!

Be warned that in the service of making things easier and more reportable cosmic-nom makes nom a little less awesome in some other ways... for instance nom has great efficiencies due to its "zero-copy" input strategy and it seems to accomplish this by passing and slicing a single &str around... cosmic-nom wraps input in an Arc and still takes great care to minimize overhead, but it breaks with the pure spirit of nom in order to provide a little ease of use.