From: "David A. Black" <dblack@...>
Date: 2007-03-14T23:28:44+09:00
Subject: Re: A simple question regarding ruby method argument

Hi --

On 3/14/07, Shin guey Wong <sgwong513@hotmail.com> wrote:
> Hi,
>
> I am new to ruby and am learning it now. Can anyone point me how to pass
> argument to method by reference? I mean that the methods/function able
> to change the value of the argument. I am running windows using win32ole
> and 1 of the method need to pass in an argument and the argument will
> modify by the win32ole methods. But I don't know how to pass argument by
> reference.

You're (almost) always passing references around anyway. Ruby doesn't
have references to references; all references are exactly one degree
away from the object to which they refer.

When you do this:

  def amend(s)
     s << " there."
  end

  str = "Hi"
  amend(str)

you've changed the original string object:

  puts str      # Hi there.

because str holds a reference to that object, and s in the method is a
copy of str (i.e., a copy of the reference, not the string).


David

-- 
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