gistfile1

#!/usr/bin/env ruby
require 'logger'
require File.dirname(__FILE__) + '/rules.rb'

class ParseError < RuntimeError; end

class Parser
  def initialize
    @logger = Logger.new(STDOUT)
    @tokenize = Proc.new {|string| string.scan(/\w+/) }
    @match_rule = Proc.new do |string|
      $rules.each_value {|value| true if string.match(value) }
    end
    @current_rule = Proc.new do |string|
      rules = ''
      $rules.select {|key, value| rules = key[0] if string.match(value) }
      rules
    end
  end
  
  def parse(str)
    # Returns array where first value is the rule
    result = []

    # Unless it matches we add the rule to our result along with the tokens
    raise ParseError, "unable to lex #{str}" unless @match_rule.call(str)
    
    result << @current_rule.call(str)
    tokens = @tokenize.call(str)
    tokens.each { |token| result << token }
    result
  end
end