Ruby on rails 如何复制类可继承访问器';Rails 3.1中的行为?
从Rails 3.1开始,Ruby on rails 如何复制类可继承访问器';Rails 3.1中的行为?,ruby-on-rails,ruby,inheritance,ruby-on-rails-3.1,Ruby On Rails,Ruby,Inheritance,Ruby On Rails 3.1,从Rails 3.1开始,class\u inheritable\u访问器产生弃用警告,告诉我改用class\u属性。但是,class\u属性在我将演示的一种重要方式中表现不同 class\u inheritable\u属性的典型用法是presenter类,如下所示: module Presenter class Base class_inheritable_accessor :presented self.presented = {} def self.prese
class\u inheritable\u访问器
产生弃用警告,告诉我改用class\u属性
。但是,class\u属性
在我将演示的一种重要方式中表现不同
class\u inheritable\u属性的典型用法是presenter类,如下所示:
module Presenter
class Base
class_inheritable_accessor :presented
self.presented = {}
def self.presents(*types)
types_and_classes = types.extract_options!
types.each {|t| types_and_classes[t] = t.to_s.tableize.classify.constantize }
attr_accessor *types_and_classes.keys
types_and_classes.keys.each do |t|
presented[t] = types_and_classes[t]
end
end
end
end
class PresenterTest < Presenter::Base
presents :user, :person
end
Presenter::Base.presented => {}
PresenterTest.presented => {:user => User, :person => Person}
这根本不是人们想要的行为。是否有其他类型的访问器以正确的方式运行,或者我是否需要完全切换到其他模式?如果没有class\u可继承的\u访问器
,我应该如何复制相同的行为?class\u属性
如果按预期使用,不会污染其父属性。确保您没有在适当的位置更改可变项
types_and_classes.keys.each do |t|
self.presented = presented.merge({t => types_and_classes[t]})
end
尝试一下,这是一种在类上设置属性的好方法,并且不会被继承或实例污染
class Class
private
# Sets Unique Variables on a resource
def inheritable_attr_accessor(*attrs)
attrs.each do |attr|
# Class Setter, Defining Setter
define_singleton_method "#{attr}=".to_sym do |value|
define_singleton_method attr do
value
end
end
# Default to nil
self.send("#{attr}=".to_sym, nil)
# Instance Setter
define_method "#{attr}=".to_sym do |value|
eval("@_#{attr} = value")
end
# Instance Getter, gets class var if nil
define_method attr do
eval("defined?(@_#{attr})") ? eval("@_#{attr}") : self.class.send(attr)
end
end
end
end
class Class
private
# Sets Unique Variables on a resource
def inheritable_attr_accessor(*attrs)
attrs.each do |attr|
# Class Setter, Defining Setter
define_singleton_method "#{attr}=".to_sym do |value|
define_singleton_method attr do
value
end
end
# Default to nil
self.send("#{attr}=".to_sym, nil)
# Instance Setter
define_method "#{attr}=".to_sym do |value|
eval("@_#{attr} = value")
end
# Instance Getter, gets class var if nil
define_method attr do
eval("defined?(@_#{attr})") ? eval("@_#{attr}") : self.class.send(attr)
end
end
end
end