What are weak-cons?

To: info-dylan@ai.mit.edu
Subject: What are weak-cons?
From: "Reinhard Häring-Oldenburg" <Felicitas.Oldenburg@t-online.de>
Date: Sun, 12 Mar 2000 09:45:01 -0500 (EST)
Organization: T-Online
Xref: traf.lcs.mit.edu comp.lang.dylan:11617

I wonder what weak-cons are precisely. They are mentionend in
the file DYLAN.TXT on
http://www.cs.indiana.edu/scheme-repository/doc.standards.html
Here is the paragraph from that:

  >  It is not possible to make a (reasonable) portable implementation of
  >  Dylan in Scheme without the addition of some form of weak pointer
  > object.  The Scheme community should consider the addition of at
  > least one such mechanism as part of the language core (weak-cons,
  >  populations, and weak hash tables are more or less interchangeable).
  > Oddly enough, Dylan hasn't made any particular mechanism visible to
  > users, although the mechanism must exist internally.  Perhaps this
  > mechanism should be coupled with the finalization proposal that has
  > been deferred to R6RS.

Moreover, how would the "(reasonable) portable implementation" look
like.

Can anybody provide explanantion or further refernces?

Thanks

Reinhard

Follow-Ups:

Re: What are weak-cons?

From: "Lyman S. Taylor" <lyman.taylor@mindspring.com>

Re: What are weak-cons?

From: "Lyman S. Taylor" <lyman.taylor@mindspring.com>