require 'mega/preinitialize'

class Module

  # Shorthand notation for creating attributes.
  #
  #   attr :r, :w!, :a=
  #
  # is equivalent to
  #
  #   attr_reader :r
  #   attr_writer :w
  #   attr_accessor :a
  #
  # A pure writer notation is not provided b/c it is so rare.
  # A "tester" shorthand is also provided (see #attr_checker)
  #
  #   attr :q?
  #
  # translates into
  #
  #   def q?
  #     @q ? true : @q
  #   end
  #--
  # :NOTE: Add this?
  #   def q!(b=true)
  #     @q = (b ? true : b)
  #   end
  #++
  #
  # Default values are also now possible using a hash.
  #
  #   cattr :a, :b => 10
  #
  # In this example @b will be initialized to 10 prior to running the
  # initilaize routine. Attributes with default values must always
  # appear at the end of the list.
  #
  # Compatability is maintained with the old version of #attr.
  # So it is still possible to write:
  #
  #   attr :a, true
  #
  # It has been expanded to allow multiple names as well:
  #
  #   attr :a, :b, :c, true
  #
  def attr(*args)

    # Allows compatibility with old definition, while also
    # extending the capabilites to allow multiple parameters.
    if TrueClass === args.last or FalseClass === args.last or NilClass === args.last
      if args.pop
        args.concat( args.collect{ |a|
          a = a.to_s.strip
          case a.slice(-1,1)
          when '='
            a[0..-2]
          when '?'
            "#{a[0..-2]}="
          else
            "#{a}="
          end
        } )
      end
    end

    # for default values
    hargs = {}
    hargs = args.pop if Hash===args.last
    unless hargs.empty?
      (class << self; self; end).instance_eval do
        default_instance_variables.update(hargs)
      end
    end

    make = {}
    (args.flatten+hargs.keys).each { |a|
      t = a.to_s.slice(-1,1)
      n = a.to_s.chomp('?').chomp('=').to_sym
      m = a.to_sym
      case t
      when '?'
        make[m] = %{ def #{n}? ; @#{n} ? true : @#{n} ; end }
      when '='
        make[m] = %{ def #{n}=(x) ; @#{n} = x ; end }
        make[n] = %{ def #{n} ; @#{n} ; end }
      else
        make[m] = %{ def #{n} ; @#{n} ; end }
      end
    }
    class_eval make.values.join("\n")

    return make.keys
  end

end #Module