How can i declare function (not method) with ruby on rails?

Question

I give you an function exemple:

def debug(var)
    raise var.inspect
end

in PHP its simple, I put

function debug($var)
{
    var_dump($var);
}

and I just have to include the file where is define this function and it is aviable in all my code where and when I want.

How can I do the same in rails app? I want a function, not a method in class and i want to be able to call it evrywhere in my code.

Answer 1

You can define the method in a module, and then include the module wherever you need access to the method, as follows:

module SomeModule
  def debug(var)
    raise var.inspect
  end
end

And then in another class:

class SomeClass
  include SomeModule

  def some_method
    debug(self)
  end
end

Answer 2

It's bad design to add global functions, btw they wont be functions: if you attach something to the global namespace, it will still be a method: remember in Ruby everything is an object.

Attach it to a module.

Example:

module Utils

  def self.debug(var)  
    raise var.inspect
  end
end

And use it wherever needed:

Utils.debug(something)

Answer 3

Let's start by saying that what you show as a function in first example is a method.

In Ruby everything is an object. So if you define some method just like in your first example, it still belongs to some object.

irb(main):001:0> self
=> main
irb(main):002:0> self.class
=> Object

You see, even if you just call irb , the context you execute code is an instance of Object class.

So what you actually want is a method which is available globally in scope of Rails application. You can achieve it by including some module right in your application (like in other answers to this question)

However, I suggest different way. Instead of creating a global method, create a class/module with that method. Classes and modules are globally accessible, so you will be able to use it everywhere (see fivedigit's answer for example).

Answer 4

Ruby中没有函数，你想要的是不可能的。