我可以從同一模塊添加類方法和實例方法嗎？

Question

新手問題：

我知道如何包括和擴展工作，我想知道的是，如果有一種方法可以從單個模塊獲取類和實例方法嗎？

這是我如何與兩個模塊做到這一點：

module InstanceMethods 
    def mod1 
     "mod1" 
    end 
end 

module ClassMethods 
    def mod2 
     "mod2" 
    end 
end 

class Testing 
    include InstanceMethods 
    extend ClassMethods 
end 

t = Testing.new 
puts t.mod1 
puts Testing::mod2 

感謝你的時間......

Answer 1

有一個共同的成語說。它利用included對象模型鉤子。每次將模塊包含到模塊/類中時，都會調用此鉤子

module MyExtensions 
    def self.included(base) 
    # base is our target class. Invoke `extend` on it and pass nested module with class methods. 
    base.extend ClassMethods 
    end 

    def mod1 
    "mod1" 
    end 

    module ClassMethods 
    def mod2 
     "mod2" 
    end 
    end 
end 

class Testing 
    include MyExtensions 
end 

t = Testing.new 
puts t.mod1 
puts Testing::mod2 
# >> mod1 
# >> mod2 

我個人喜歡將實例方法組合到一個嵌套模塊中。據我所知，這是不太被人接受的做法。

module MyExtensions 
    def self.included(base) 
    base.extend ClassMethods 
    base.include(InstanceMethods) 

    # or this, if you have an old ruby and the line above doesn't work 
    # base.send :include, InstanceMethods 
    end 

    module InstanceMethods 
    def mod1 
     "mod1" 
    end 
    end 

    module ClassMethods 
    def mod2 
     "mod2" 
    end 
    end 
end 

Answer 2

module Foo 
def self.included(m) 
    def m.show1 
    p "hi" 
    end 
end 

def show2 
    p "hello" 

end 
end 

class Bar 
include Foo 
end 

Bar.new.show2 #=> "hello" 
Bar.show1 #=> "hi" 

Answer 3

是。這是你所期望的完全一樣簡單，由於紅寶石的天才：

module Methods 
    def mod 
     "mod" 
    end 
end 

class Testing 
    include Methods # will add mod as an instance method 
    extend Methods # will add mod as a class method 
end 

t = Testing.new 
puts t.mod 
puts Testing::mod 

或者，你可以這樣做：

module Methods 
    def mod1 
     "mod1" 
    end 

    def mod2 
     "mod2" 
    end 
end 

class Testing 
    include Methods # will add both mod1 and mod2 as instance methods 
    extend Methods # will add both mod1 and mod2 as class methods 
end 

t = Testing.new 
puts t.mod1 
puts Testing::mod2 
# But then you'd also get 
puts t.mod2 
puts Testing::mod1