# Moreover, it gracefully handles module dependencies. Given a Foo module and a Bar module which depends on the former, we would typically write the following:
# Moreover, it gracefully handles module dependencies. Given a +Foo+ module and a +Bar+
# module which depends on the former, we would typically write the following:
#
# module Foo
# def self.included(base)
# # Define some :enhanced_method for Host class
# base.class_eval do
# def self.enhanced_method
# # Do enhanced stuff
# def self.method_injected_by_foo
# ...
# end
# end
# end
...
...
@@ -52,7 +52,7 @@ module ActiveSupport
#
# module Bar
# def self.included(base)
# base.send(:enhanced_method)
# base.method_injected_by_foo
# end
# end
#
...
...
@@ -61,23 +61,13 @@ module ActiveSupport
# include Bar # Bar is the module that Host really needs
# end
#
# But why should Host care about Bar's dependencies, namely Foo? We could try to hide these from Host directly including Foo in Bar:
#
# module Foo
# def self.included(base)
# # Define some :enhanced_method for Host class
# base.class_eval do
# def self.enhanced_method
# # Do enhanced stuff
# end
# end
# end
# end
# But why should +Host+ care about +Bar+'s dependencies, namely +Foo+? We could try to hide
# these from +Host+ directly including +Foo+ in +Bar+:
#
# module Bar
# include Foo
# def self.included(base)
# base.send(:enhanced_method)
# base.method_injected_by_foo
# end
# end
#
...
...
@@ -85,8 +75,8 @@ module ActiveSupport
# include Bar
# end
#
# Unfortunately this won't work, since when Foo is included, its <tt>base</tt> is Bar module, not Host class.
# With <tt>ActiveSupport::Concern</tt>, module dependencies are properly resolved:
# Unfortunately this won't work, since when +Foo+ is included, its <tt>base</tt> is the +Bar+ module,
# not the +Host+ class. With <tt>ActiveSupport::Concern</tt>, module dependencies are properly resolved:
#
# require 'active_support/concern'
#
...
...
@@ -94,8 +84,8 @@ module ActiveSupport
# extend ActiveSupport::Concern
# included do
# class_eval do
# def self.enhanced_method
# # Do enhanced stuff
# def self.method_injected_by_foo
# ...
# end
# end
# end
...
...
@@ -106,12 +96,12 @@ module ActiveSupport
# include Foo
#
# included do
# self.send(:enhanced_method)
# self.method_injected_by_foo
# end
# end
#
# class Host
# include Bar # Host only needs to care about Bar without needing to know about its dependencies
# include Bar # works, Bar takes care now of its dependencies