#--
# Author::    Tyler Rick
# Copyright:: Copyright (c) 2007 QualitySmith, Inc.
# License::   Ruby License
# Submit to Facets?:: Yes
# Developer notes::
# * Based on /usr/lib/ruby/gems/1.8/gems/facets-1.8.54/lib/facets/core/module/attr_tester.rb
# * Hey Thomas, don't you think Module#attr_tester should only create the read-only a? method and have another method that creates the writer (like there how we have attr_reader, _writer, and _accessor?) ? "tester" does not imply "setter" in my mind...
#++

class Module
  # This creates two methods for each given variable name. One is used to test
  # the attribute and the other is used to set or toggle it.
  #
  #   attr_tester :a
  #
  # is equivalent to
  #
  #   def self.a?
  #     @@a ? true : @@a
  #   end
  #
  #   def self.a!(switch=Exception)
  #     if switch == Exception
  #       @@a = !@@a
  #     else
  #       @@a = switch ? true : @@a
  #       self
  #     end
  #   end
  #
  # Works for both classes and modules.
  #
  def mattr_tester(*args)

    make = {}
    args.each { |a|
      # Initialize it first so that we won't have any NameErrors.
      module_eval %{ @@#{a} = nil if !defined?(@@#{a}) }, __FILE__, __LINE__

      make["#{a}?".to_sym] = %{
        def self.#{a}?(true_value=true)
          @@#{a} ? true_value : @@#{a}
        end
      }
      make["#{a}!".to_sym] = %{
        def self.#{a}!(switch=Exception)
          if switch == Exception
            @@#{a} = !@@#{a}
          else
            @@#{a} = switch ? true : @@#{a}
            self
          end
        end
      }
    }
    module_eval make.values.join("\n"), __FILE__, __LINE__

    return make.keys
  end
end







#  _____         _
# |_   _|__  ___| |_
#   | |/ _ \/ __| __|
#   | |  __/\__ \ |_
#   |_|\___||___/\__|
#
=begin test
require 'test/unit'
require 'rubygems'
require 'qualitysmith_extensions/object/ignore_access'


class TheTest < Test::Unit::TestCase
  class C
    mattr_tester :a
  end
  module M
    mattr_tester :a
  end

  def test_cattr_tester_exclamation
    C.access.class_variable_set(:@@a, false)
    assert_equal(false, C.a?)   # otherwise would have been nil
    C.a!
    assert_equal(true, C.a?)
    C.a!
    assert_equal(false, C.a?)
  end
  def test_cattr_tester_return
    C.a!
    assert_equal(true, C.a?)
    C.a!("whatever")
    assert_equal(true, C.a?)   # Still returns a boolean even though we set it to a string.
  end

  def test_mattr_tester_exclamation
    assert_equal(nil, M.a?)
    M.a!
    assert_equal(true, M.a?)
    M.a!
    assert_equal(false, M.a?)
  end
  def test_mattr_tester_return
    M.a!
    assert_equal(true, M.a?)
    M.a!("whatever")
    assert_equal(true, M.a?)   # Still returns a boolean even though we set it to a string.
  end

end
=end