From: ludo@gnu.org (Ludovic Courtès)
To: guile-devel@gnu.org
Subject: Re: srfe records in reworked match
Date: Fri, 23 Apr 2010 11:23:33 +0200 [thread overview]
Message-ID: <87ochattd6.fsf@gnu.org> (raw)
In-Reply-To: 201004230952.42913.stefan.tampe@spray.se
Hi,
stefan <stefan.tampe@spray.se> writes:
> On Wednesday 21 April 2010 10:40:29 am Ludovic Courtès wrote:
>> As noted in Shinn’s match-cond-expand.scm, this record matching form is
>> not ideal:
>>
>> ;; Annoying unhygienic record matching. Record patterns look like
>> ;; ($ record fields...)
>> ;; where the record name simply assumes that the same name suffixed
>> ;; with a "?" is the correct predicate.
>>
>
> Entering,
>
> scheme@(guile-user)> (macroexpand '(n? x))
> (if (struct? x) (eq? (struct-vtable x) n) #f)
That’s an implementation detail that you should ignore. :-)
Just have users write:
(($ n? a b c) ...)
Where ‘n?’ is bound to the record type predicate, and have ‘match’
invoke that record type predicate.
Thanks,
Ludo’.
next prev parent reply other threads:[~2010-04-23 9:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-20 13:14 srfe records in reworked match stefan
2010-04-21 8:40 ` Ludovic Courtès
[not found] ` <07487229-BEA5-49C8-B73F-83370F028513@spray.se>
2010-04-21 11:47 ` Ludovic Courtès
2010-04-22 11:13 ` Andy Wingo
2010-04-22 12:27 ` Ludovic Courtès
2010-04-22 12:52 ` Andy Wingo
2010-04-22 12:57 ` Ludovic Courtès
2010-04-22 13:48 ` Andy Wingo
2010-04-22 17:09 ` stefan
2010-04-23 7:52 ` stefan
2010-04-23 9:23 ` Ludovic Courtès [this message]
2010-04-23 20:21 ` stefan
2010-04-28 8:40 ` Ludovic Courtès
[not found] <CCF7F725-F332-40DE-8193-65FB81ADD08C@spray.se>
2010-04-28 13:50 ` Stefan
2010-05-03 12:38 ` Ludovic Courtès
2010-05-03 13:35 ` Stefan
2010-05-03 13:51 ` Ludovic Courtès
2010-05-03 16:24 ` stefan
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