訪問類實例方法如實例方法

Question

class Foo 
    def self.bar 
    puts "foobar" 
    end 

    def bar 
    self.class.bar 
    end 
end 

我想避免需要定義實例方法bar。有沒有辦法自動使類方法作爲實例方法可訪問？也許有一些method_missing?魔法？

Answer 1

試着這麼做：

class Foo 

    def self.bar 
    puts "foobar" 
    end 

    def respond_to? name 
    super or self.class.respond_to? name 
    end 

    def method_missing name, *args, &block 
    if self.class.respond_to? name 
     self.class.send name, *args, &block 
    else 
     super 
    end 
    end 

end 

你也可以做到這一點（簡版）：

module ChainsToClass 
    def respond_to? name 
    super or self.class.respond_to? name 
    end 
    def method_missing name, *args, &block 
    if self.class.respond_to? name 
     self.class.send name, *args, &block 
    else 
     super 
    end 
    end 
end 

class Foo 
    def self.bar 
    puts "foobar" 
    end 
end 

Foo.send :include, ChainsToClass 

Answer 2

最簡單的方法是定義在一個子模塊的方法和延伸，它包括進入等級：

class Foo 

    module FooMethods 
    def bar 
     puts "foobar" 
    end 
    end 

    # Add methods from module FooMethods as class methods to class Foo 
    extend FooMethods 

    # Add methods from module FooMethods as instance methods to class Foo 
    include FooMethods 
end