Documentation just before Concern module
This commit is contained in:
parent
98818f92b8
commit
ca87d0a395
|
@ -1,119 +1,119 @@
|
|||
# A typical module looks like this:
|
||||
#
|
||||
# module M
|
||||
# def self.included(base)
|
||||
# base.send(:extend, ClassMethods)
|
||||
# base.send(:include, InstanceMethods)
|
||||
# scope :foo, :conditions => { :created_at => nil }
|
||||
# end
|
||||
#
|
||||
# module ClassMethods
|
||||
# def cm; puts 'I am a class method'; end
|
||||
# end
|
||||
#
|
||||
# module InstanceMethods
|
||||
# def im; puts 'I am an instance method'; end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# By using <tt>ActiveSupport::Concern</tt> the above module could instead be written as:
|
||||
#
|
||||
# require 'active_support/concern'
|
||||
#
|
||||
# module M
|
||||
# extend ActiveSupport::Concern
|
||||
#
|
||||
# included do
|
||||
# scope :foo, :conditions => { :created_at => nil }
|
||||
# end
|
||||
#
|
||||
# module ClassMethods
|
||||
# def cm; puts 'I am a class method'; end
|
||||
# end
|
||||
#
|
||||
# module InstanceMethods
|
||||
# def im; puts 'I am an instance method'; end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# 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
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# module Bar
|
||||
# def self.included(base)
|
||||
# base.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# include Foo # We need to include this dependency for Bar
|
||||
# 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
|
||||
#
|
||||
# module Bar
|
||||
# include Foo
|
||||
# def self.included(base)
|
||||
# base.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# 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:
|
||||
#
|
||||
# require 'active_support/concern'
|
||||
#
|
||||
# module Foo
|
||||
# extend ActiveSupport::Concern
|
||||
# included do
|
||||
# class_eval do
|
||||
# def self.enhanced_method
|
||||
# # Do enhanced stuff
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# module Bar
|
||||
# extend ActiveSupport::Concern
|
||||
# include Foo
|
||||
#
|
||||
# included do
|
||||
# self.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# include Bar # Host only needs to care about Bar without needing to know about its dependencies
|
||||
# end
|
||||
#
|
||||
module ActiveSupport
|
||||
# A typical module looks like this:
|
||||
#
|
||||
# module M
|
||||
# def self.included(base)
|
||||
# base.send(:extend, ClassMethods)
|
||||
# base.send(:include, InstanceMethods)
|
||||
# scope :foo, :conditions => { :created_at => nil }
|
||||
# end
|
||||
#
|
||||
# module ClassMethods
|
||||
# def cm; puts 'I am a class method'; end
|
||||
# end
|
||||
#
|
||||
# module InstanceMethods
|
||||
# def im; puts 'I am an instance method'; end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# By using <tt>ActiveSupport::Concern</tt> the above module could instead be written as:
|
||||
#
|
||||
# require 'active_support/concern'
|
||||
#
|
||||
# module M
|
||||
# extend ActiveSupport::Concern
|
||||
#
|
||||
# included do
|
||||
# scope :foo, :conditions => { :created_at => nil }
|
||||
# end
|
||||
#
|
||||
# module ClassMethods
|
||||
# def cm; puts 'I am a class method'; end
|
||||
# end
|
||||
#
|
||||
# module InstanceMethods
|
||||
# def im; puts 'I am an instance method'; end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# 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
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# module Bar
|
||||
# def self.included(base)
|
||||
# base.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# include Foo # We need to include this dependency for Bar
|
||||
# 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
|
||||
#
|
||||
# module Bar
|
||||
# include Foo
|
||||
# def self.included(base)
|
||||
# base.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# 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:
|
||||
#
|
||||
# require 'active_support/concern'
|
||||
#
|
||||
# module Foo
|
||||
# extend ActiveSupport::Concern
|
||||
# included do
|
||||
# class_eval do
|
||||
# def self.enhanced_method
|
||||
# # Do enhanced stuff
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# module Bar
|
||||
# extend ActiveSupport::Concern
|
||||
# include Foo
|
||||
#
|
||||
# included do
|
||||
# self.send(:enhanced_method)
|
||||
# end
|
||||
# end
|
||||
#
|
||||
# class Host
|
||||
# include Bar # Host only needs to care about Bar without needing to know about its dependencies
|
||||
# end
|
||||
#
|
||||
module Concern
|
||||
def self.extended(base)
|
||||
base.instance_variable_set("@_dependencies", [])
|
||||
|
|
Loading…
Reference in New Issue