treetop styleguide example

css.treetop

grammar Css
  rule body
    (styleguide / comment)* {
      def val
        Hash[
          elements.map(&:val).compact
        ]
      end
    }
  end

  rule styleguide
    header selector definition
    {
      def val
        header, selector, _ = elements
        [selector.val, header.val]
      end
    }
  end

  rule header
     (whitespace)*
     '/*' (whitespace)* '@styleguide'
      (
        !'*/'
        (. / "\n")
      )*
      '*/'
      (whitespace)*
    {
      def val
        elements[4].text_value.strip
      end
    }
  end

  rule selector
    ("." / "#") [\w]+ {
      def val
        text_value
      end
    }
  end

  rule definition
    (whitespace)*
    "{"
    (
      !"}"
      (. / "\n")
    )*
    "}"
    (whitespace)*
  end

  rule comment
    (whitespace)*
    "/*"
    (
      !"*/"
      (. / "\n")
    )*
    "*/"
    (whitespace)*
    {
      def val
      end
    }
  end

  rule whitespace
    [\s]+
  end
end

styleguide.rb

#!/usr/bin/env ruby

require 'treetop'
require 'pp'
require_relative 'css'

parser = CssParser.new
if styleguide = parser.parse('
/* @styleguide

  this is a test

*/
.foo { color: red; }

/*   @styleguide test 2 */
#bar {


}

/* this is a regular comment */

/*@styleguide test 3 */
.foo2 {
  color: black;
  }
/*
   @styleguide

   test 4*/
   .bar4 {}
')
  pp styleguide.val
else
  fail 'dang'
end