[ruby-talk:21811] Re: Transparent Proxies

Paul Brannan <[e-mail]> wrote in message news:<[e-mail]>...
> On Thu, 27 Sep 2001, Jason Voegele wrote:
> > C++ tends to do this by allowing pointers to "fault" and catching the
> > exception.  I don't think I can do this in Ruby, and I'm not sure that
> > I'd want to anyway.
> 
> I'm not sure what you mean here.  Can you provide an example?

Well, as Ned Konz pointed out, this isn't a portable solution.  The
first sentence should have read "Some C++ object databases do this
by..."

The basic idea is that when an object is loaded from the database,
other objects that it references (via pointers) are not necessarily
loaded at that same time.  Instead, the pointers are initialized so
that they point to an illegal location in memory.  When that pointer
is dereferenced, some operating systems will trap the illegal access
and throw an exception.  That exception, indicating that another
object must be loaded from the database, can be handled by loading the
object that's really supposed to be referenced by the pointer.  The
pointer is then updated to point to the newly loaded object.

Anyway, I've come up with what I believe is a good solution for Ruby,
and I'll post it here under the subject "Pseudo-Become operator for
Ruby".

Thanks for your help,
Jason Voegele