From: Rick DeNatale <rick.denatale@...>
Date: 2007-10-03T04:38:38+09:00
Subject: Re: Reference vs. Reference

I'm catching up after being away for a few days, and this seems to
have been a hot topic lately.

I've seen the term call by object reference used many times in the
past to distinguish what happens in languages like Ruby and Smalltalk
from the usual meaning of call by reference.

The difference is that call by reference implies giving the called
routine read/write access to the variable which holds a reference to
some data.  And call by object reference gives the called method read
access to a reference to an object.  The called routine can NOT change
the reference, it can only invoke methods on the referenced object.

Note that although Ruby does allow assignment to a parameter
'variable' this is only moving a 'sticky note'  to use Austin Z's nice
analogy.

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/