From: Nathan Morse <nmorse@...>
Date: 2006-02-24T12:58:38+09:00
Subject: Everything's an object, right?

I was talking to a coworker today about the Ruby, and we were
discussing how in Ruby everything is an object.  He wondered if
everything was call-by-reference, and my knee jerk reaction was yes.

Then I ran the following irb session....

------------------- START IRB -------------------------

def foo(x)
  x = 'k' + x[1..x.size]
  x
end

def bar(x)
  x[0] = 'k'
  x
end

k = 'crazy'
=> "crazy"

foo(k)
=> "krazy"

k
=> "crazy"       # !?!?!?!?!

bar(k)
=> "krazy"

k
=> "krazy"       # As expected.

------------------- END IRB -------------------------

Can someone explain to me why the method foo() doesn't modify k while
bar() does?  I suppose it has something to do with the fact that I'm
using an asignment statement in foo() but modifiying the parameter
"in-place" for bar().  Still, I'm a bit confused.

[author's note: Yes, I know my example isn't very "Rubyish".  I just
want to get a better handle on the language.]

Thanks!

-Nathan