A Rack-like functionality for OptionParser

parsable.rb

module Parsable
  def self.included(mod)
    class << mod
      attr_accessor :child_parser
    end
    mod.child_parser = NullParsable.new
    mod.class_eval do
      def child_parser
        self.class.child_parser
      end
    end
  end
  def parser
    self.child_parser.parser
  end
  def option_parser
  end
  def apply_parser
    option_parser
    yield
    after_parse
  end
  def child_parser
  end
  def parse!(vals=ARGV)
    apply_parser do
      child_parser.parse!(vals)
    end
  end
  def after_parse
  end

  class NullParsable
    include Parsable
    def parser
      @parser ||= OptionParser.new
    end
    def child_parser
      parser
    end
  end
end


class TestOptions
  attr_accessor :options

  include Parsable
  self.child_parser = TestNestedOptions.new #TODO: rewrite to
  #rack-like mount
  
  def initialize
    self.options = {}
  end
  def option_parser
    self.parser.on('-a') do
      options[:a] = 1
    end
  end
  def after_parse
    puts "a=#{options[:a]}" if options[:a]
  end
end
class TestNestedOptions
  attr_accessor :options
  include Parsable
  def initialize
    self.options = {}
  end
  def option_parser
    self.parser.on('-b') do
      options[:b] = 2
    end
  end
  def after_parse
    puts "b=#{options[:b]}" if options[:b]
  end
end

#begin; t=TestOptions.new; t.parse!(ARGV); [t.options,t.child_parser.options]; end