gistfile1.rb

grammar Less
  rule ruleset
    (ws selectors ws "{" ruleset "}" ws / declaration)+ <Descend> { 
      def build(env) super env, 1 end
    } / 
    declaration* <Descend> {
      def build(env) super env, 1 end
    }
  end
  
  #
  # div, .class, body > p
  #
  rule selectors
    selector ',' selectors <Descend>
    / selector {
      def build env
        log text_value, env
        elements.each {|e| e.build env if e.respond_to? :build}
      end
    }
  end
  
  #
  # div > p a
  #
  rule selector
    element select selector <Descend>
    / element <Descend> {
      def build env
        log text_value, env
      end
    }
  end
  
  #
  # div | .class | #id | *
  #
  rule element
    ([#.]? [-a-zA-Z0-9_\[\]|~=']+ / '*') {
      def build env
        log text_value, env
      end
    }
  end
  
  rule select
    (' ' / '>') {
      def build env
        env[:depth] += 1
        #log text_value, env
      end
    }
  end
  
  #
  # @my-var: 12px;
  # height: 100%;
  #
  rule declaration
    ws name:(property / variable) s ':' s value s ';' ws {
      def build env
        log "#{name.text_value}: #{value.text_value}", env
      end
    }
  end
  
  rule declarations
      declaration* <Descend>
  end
  
  rule value
    [^\n;]+
  end
  
  rule property
    [-a-z0-9_]+
  end
  
  rule variable
    '@' property {
      def build env
        #puts "* #{property.text_value}"
      end
    }
  end
  
  rule mixin
    selectors ';'
  end
  
  # Space
  rule s
    [ ]*
  end
  
  # Whitespace
  rule ws
    [\n ]*
  end
  
  # Non-whitespace
  rule ns
    ![\n ] .
  end
end