[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

- and / with one argument should be identity functions.

   Date: 13 Nov 89 17:17:21 GMT
   From: Via Fons Botman <mcsun!hp4nl!star.cs.vu.nl!xerox@uunet.uu.net>

   PLease, let's *not* define (- X) and (/ X) to be something else
   than X.

   Besides that, it may be cute, but it is neither clear nor
   consistent, and therefore not "in the spirit of Scheme".

While it may be "cute" to use this pun, I think your argument about
clarity is incorrect: it is unusual for someone to be confused by this
usage of `-' (I don't know about `/'; I suspect it is rarely called
with one argument).

In practical terms, it is very much too late to reconsider this
decision.  Both the R4RS and the Draft Standard for Scheme endorse
this inconsistency, and I can't recall any serious debate concerning
it.  Perhaps if this issue had been raised five years ago something
might have been done, but at this point the inertia of standards and
implementations make such a change difficult; and this is especially
true as it is unlikely to be viewed (by those standardizers and
implementors) as being worth much effort.

Unfortunately this means that the Scheme community is a kind of
authoritarian structure -- but the standardization process is open to
anyone who cares to participate, so you too can be one of those in
authority.  There are two relevant mailing lists:


Interested parties should know that because the Draft Standard is
nearly completed, significant reexamination of basic issues on the
"scheme-standard" mailing list is inappropriate.  The "rrrs-authors"
list is currently clearing up final details of R4RS, and debate is
welcomed on interesting issues for R5RS.

Archives of past discussions on each list are available by anonymous
ftp from "zurich.ai.mit.edu" in the directory "pub/scheme-mail/".