我可以在不包含Ruby模块的情况下调用它的实例方法吗? [英] Can I invoke an instance method on a Ruby module without including it?

问题描述

我有一个声明许多实例方法的模块

I have a module which declares a number of instance methods

module UsefulThings
  def get_file; ...
  def delete_file; ...

  def format_text(x); ...
end

我想从一个类中调用其中一些方法.通常在红宝石中的操作方式如下:

And I want to call some of these methods from within a class. How you normally do this in ruby is like this:

class UsefulWorker
  include UsefulThings

  def do_work
    format_text("abc")
    ...
  end
end

问题

include UsefulThings从UsefulThings引入了 all 个方法.在这种情况下，我只需要format_text，而明确地不希望get_file和delete_file.

Problem

include UsefulThings brings in all of the methods from UsefulThings. In this case I only want format_text and explicitly do not want get_file and delete_file.

我可以看到几种可能的解决方案:

I can see several possible solutions to this:

1. 以某种方式直接在模块上调用方法，而无需在任何地方包含它
   • 我不知道如何/是否可以做到这一点. (因此出现这个问题)

1. Somehow invoke the method directly on the module without including it anywhere
   • I don't know how/if this can be done. (Hence this question)

• 我也不知道如何/是否可以做到

• 这可以工作，但是匿名代理类是一种黑客.好吧.

• 这也将起作用，并且可能是我能想到的最好的解决方案，但是我宁愿避免使用它，因为这样最终会导致大量模块的扩散-管理该模块很麻烦

为什么单个模块中有许多不相关的功能?这是来自Rails应用程序的ApplicationHelper，我们的团队事实上已将其确定为所有不够具体的东西的垃圾场.大多数情况下，独立的实用程序方法随处可见.我可以将其分解为单独的助手，但其中有30个，每个助手只有一种方法...这似乎没有用

Why are there lots of unrelated functions in a single module? It's ApplicationHelper from a rails app, which our team has de-facto decided on as the dumping ground for anything not specific enough to belong anywhere else. Mostly standalone utility methods that get used everywhere. I could break it up into seperate helpers, but there'd be 30 of them, all with 1 method each... this seems unproductive

推荐答案

如果将模块上的方法转换为模块函数，则可以简单地从Mods调用它，就好像它已被声明为

If a method on a module is turned into a module function you can simply call it off of Mods as if it had been declared as

module Mods
  def self.foo
     puts "Mods.foo(self)"
  end
end

下面的module_function方法将避免破坏包含所有Mod的任何类.

The module_function approach below will avoid breaking any classes which include all of Mods.

module Mods
  def foo
    puts "Mods.foo"
  end
end

class Includer
  include Mods
end

Includer.new.foo

Mods.module_eval do
  module_function(:foo)
  public :foo
end

Includer.new.foo # this would break without public :foo above

class Thing
  def bar
    Mods.foo
  end
end

Thing.new.bar  

但是，我很好奇为什么首先将一组不相关的功能全部包含在同一个模块中?

However, I'm curious why a set of unrelated functions are all contained within the same module in the first place?

已编辑，以显示如果在module_function :foo

这篇关于我可以在不包含Ruby模块的情况下调用它的实例方法吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！