Subject: Re: best standard? [was Re: RFC: Lisp/Scheme ...]
From: (Rob Warnock)
Date: 2000/08/17
Newsgroups: comp.lang.lisp
Message-ID: <8ngd7n$hb56r$>
Kent M Pitman  <> wrote:
| The issue, which really I'm the only one I've ever heard get excited about,
| is that call/cc gets one too few bits as an argument...
| ...two obvious ways, and probably some others.  The two ways I've cited are:
|  (1) add an extra arg to call/cc saying if you want a one-time use ...
|  (2) keep call/cc as it is, but make every continuation take an argument...

Several Schemes agree with the general sentiments you voice, but have
chosen to:

   (3) Leave call/cc as it is, and add a separate primitive to reify
       "one-shot" continuations.

[MzScheme calls this "call/ec" a.k.a. "call-with-escaping-continuation".
It also provide the convenience macros "let/cc" & "let/ec". More info
at <URL:>.]


Rob Warnock, 41L-955
Applied Networking
Silicon Graphics, Inc.		Phone: 650-933-1673
1600 Amphitheatre Pkwy.		PP-ASEL-IA
Mountain View, CA  94043