如何从Ruby模块中仅导入几个函数？

Suppose I have a module with the methods : function1,function2,function3. I want to import function1 and function2 but not function3. Is there a way to do this in ruby?

假设我有一个带有方法的模块:function1,function2,function3。我想导入function1和function2但不导入function3。有没有办法在红宝石中做到这一点?

3 个解决方案

#1

Not sure if there is a clean way to just add the methods you want, but you can remove the methods that you don't want by using undef_method.

不确定是否有一种干净的方法来添加所需的方法,但您可以使用undef_method删除不需要的方法。

module Foo
  def function1
  end

  def function2
  end

  def function3
  end
end

module MiniFoo
  include Foo
  not_wanted_methods = Foo.instance_methods - %w(function1 function2)
  not_wanted_methods.each {|m| undef_method m}
end

class Whatever
  include MiniFoo
end

#2

Similar solution but a tad more automatic. I have no idea what kind of weird things that can happen though.

类似的解决方案,但更自动。我不知道会发生什么样的奇怪事情。

module Foo
  def m1
    puts "Hello from m1"
  end

  def m2
    puts "Hllo from m2"
  end
end

class Module
  alias :__include__ :include
  def include(mod, *methods)
    if methods.size > 0
        tmp  = mod.dup
        new_mod = Object.const_set("Mod#{tmp.object_id}", tmp)
        toremove = new_mod.instance_methods.reject { |m| methods.include? m.to_sym }
        toremove.each { |m| new_mod.send(:undef_method, m) }
        __include__(new_mod)
    else
      __include__(mod)
    end
  end
end

class Bar
  include Foo
end

class Baz
  include Foo, :m2
end

bar = Bar.new
baz = Baz.new
p bar.methods - Object.methods
p baz.methods - Object.methods

=>

["m1", "m2"]
["m2"]

#3

Assuming you control the source code to the module, I think the cleanest way would be to split the module in to more, uh, modular pieces.

假设您控制模块的源代码,我认为最干净的方法是将模块拆分为更多,呃,模块化的部分。

If you only want some parts of a module, that's a pretty good sign that you could refactor that module into multiple modules that have less responsibility.

如果你只想要一个模块的某些部分,这是一个非常好的迹象,你可以将该模块重构为多个负责较少的模块。

#1