From: dblack@...
Date: 2007-01-27T09:43:57+09:00
Subject: Re: pass by reference?

Hi --

On Sat, 27 Jan 2007, Martin C. Martin wrote:

>
>
> Phrogz wrote:
>> If you pass an immutable type by reference, does it make a sound?
>> Er, I mean...
>> If you passed an immutable type by reference, how would you know that
>> it wasn't passed by value?
>
> Is there any way for the function you're calling to modify the value of the 
> variable in the caller?  Pass by reference can do that.

You can modify the object to which the variable refers:

   def change_me(obj)
     obj << "hi"
   end

   arr = [1,2,3]
   change_me(arr)
   p arr          # [1, 2, 3, "hi"]

In this example, arr contains a reference to an array.  In change_me,
obj contains another copy of the same reference, so you can use it to
manipulate and change the original array.

I still wouldn't call this pass by reference (see my earlier post in
this thread).


David

-- 
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