[r6rs-discuss] an essay on language design

From: AndrevanTonder <andre>
Date: Tue, 10 Jul 2007 09:07:46 -0400 (EDT)

On Tue, 10 Jul 2007, William D Clinger wrote:

> * Allow the <parent rtd> and <parent cd> of a
> parent-rtd clause to be arbitrary expressions,
> as in the 5.97 draft. (Notice, however, that
> the <record name> bound by a define-record-type
> is now an ordinary variable and can serve as the
> <parent rtd> without having to resort to a use
> of record-type-descriptor).
>
> * Extend the parent clause to allow any expression,
> which must of course evaluate to an rtd.

Just a small note: Then the difference between (parent ---)
and (parent-rtd ---) would be that parent-rtd takes a second
cd argument. Since (parent ---) takes an rtd, (parent-rtd ---)
would be a very unfortunate choice of name for the two-argument
variant. If this proposal were adopted, it would perhaps be
better to merge both functions into a (parent ---) clause with
an optional second argument.

After all the work that has gone into r6rs, might it not be
worthwhile delaying (g)ratification for another version or two?

Andre
Received on Tue Jul 10 2007 - 09:07:46 UTC