syntax

This is a project built with marpa.

Flexible syntax highlighter.

Installation

Add this to your application's shard.yml:

dependencies:
  syntax:
    github: omarroth/syntax.cr

Usage

require "syntax"

highlighter = Syntax::Highlighter.new
grammar = <<-'END_BNF'
# Grammar from https://metacpan.org/pod/distribution/Marpa-R2/pod/Semantics.pod
:start ::= Expression
Expression ::= Number
| '(' Expression ')' bgcolor => salmon
|| Expression '**' Expression bgcolor => red
|| Expression '*' Expression bgcolor => yellow color => black
| Expression '/' Expression bgcolor => green color => orange
|| Expression '+' Expression bgcolor => blue color => orange
| Expression '-' Expression bgcolor => cyan color => black

Number ~ [\d]+

:discard ~ whitespace
whitespace ~ [\s]+
END_BNF

input = "10 + (6 - 1 / 3) * 2"

highlighter.highlight(input, grammar)

Contributing

1. Fork it (https://github.com/omarroth/syntax.cr/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• omarroth Omar Roth - creator, maintainer