# <!-- rdoc-file=lib/delegate.rb -->
# A concrete implementation of Delegator, this class provides the means to
# delegate all supported method calls to the object passed into the constructor
# and even to change the object being delegated to at a later time with
# #__setobj__.
#
#     class User
#       def born_on
#         Date.new(1989, 9, 10)
#       end
#     end
#
#     require 'delegate'
#
#     class UserDecorator < SimpleDelegator
#       def birth_year
#         born_on.year
#       end
#     end
#
#     decorated_user = UserDecorator.new(User.new)
#     decorated_user.birth_year  #=> 1989
#     decorated_user.__getobj__  #=> #<User: ...>
#
# A SimpleDelegator instance can take advantage of the fact that SimpleDelegator
# is a subclass of `Delegator` to call `super` to have methods called on the
# object being delegated to.
#
#     class SuperArray < SimpleDelegator
#       def [](*args)
#         super + 1
#       end
#     end
#
#     SuperArray.new([1])[0]  #=> 2
#
# Here's a simple example that takes advantage of the fact that
# SimpleDelegator's delegation object can be changed at any time.
#
#     class Stats
#       def initialize
#         @source = SimpleDelegator.new([])
#       end
#
#       def stats(records)
#         @source.__setobj__(records)
#
#         "Elements:  #{@source.size}\n" +
#         " Non-Nil:  #{@source.compact.size}\n" +
#         "  Unique:  #{@source.uniq.size}\n"
#       end
#     end
#
#     s = Stats.new
#     puts s.stats(%w{James Edward Gray II})
#     puts
#     puts s.stats([1, 2, 3, nil, 4, 5, 1, 2])
#
# Prints:
#
#     Elements:  4
#      Non-Nil:  4
#       Unique:  4
#
#     Elements:  8
#      Non-Nil:  7
#       Unique:  6
#
class SimpleDelegator < Delegator
  public

  # <!--
  #   rdoc-file=lib/delegate.rb
  #   - __getobj__() { || ... }
  # -->
  # Returns the current object method calls are being delegated to.
  #
  def __getobj__: () -> untyped

  # <!--
  #   rdoc-file=lib/delegate.rb
  #   - __setobj__(obj)
  # -->
  # Changes the delegate object to *obj*.
  #
  # It's important to note that this does **not** cause SimpleDelegator's methods
  # to change.  Because of this, you probably only want to change delegation to
  # objects of the same type as the original delegate.
  #
  # Here's an example of changing the delegation object.
  #
  #     names = SimpleDelegator.new(%w{James Edward Gray II})
  #     puts names[1]    # => Edward
  #     names.__setobj__(%w{Gavin Sinclair})
  #     puts names[1]    # => Sinclair
  #
  def __setobj__: (untyped obj) -> untyped
end