From: ludo@gnu.org (Ludovic Courtès)
To: Mark H Weaver <mhw@netris.org>
Cc: guile-user@gnu.org
Subject: Re: A value for "nothing"
Date: Tue, 28 Aug 2018 09:52:21 +0200 [thread overview]
Message-ID: <87bm9norm2.fsf@gnu.org> (raw)
In-Reply-To: <874lfftwrt.fsf@netris.org> (Mark H. Weaver's message of "Mon, 27 Aug 2018 15:49:42 -0400")
Hello,
Mark H Weaver <mhw@netris.org> skribis:
> ludo@gnu.org (Ludovic Courtès) writes:
>
>> I would suggesting returning zero values, using:
>>
>> (values)
>>
>> That way, if a caller wrongfully attempts to get at the return value of
>> that procedure, it’ll get an error.
>>
>> Fibers does that in several places, and I think it’s a good convention
>> as it conveys exactly what you want.
>
> You cannot store (values) in a variable or data structure, so it
> wouldn't work here.
>
> The issue under discussion is how to represent MessagePack's "nil",
> which is one of the possible values that a MessagePack can have,
> alongside booleans, integers, floats, strings, arrays, etc.
Oops, sorry for the off-topic reply!
In this context, my preference would be for a singleton type:
(define-record-type <nothing>
(nothing)
nothing?)
Ludo’.
next prev parent reply other threads:[~2018-08-28 7:52 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-26 10:13 A value for "nothing" HiPhish
2018-08-26 17:21 ` Thomas Morley
2018-08-26 17:27 ` Joshua Branson
2018-08-26 17:49 ` John Cowan
2018-08-27 4:52 ` Mark H Weaver
2018-08-27 13:00 ` John Cowan
2018-08-27 21:29 ` Mark H Weaver
2018-08-27 21:32 ` Mark H Weaver
2018-08-26 20:07 ` Mark H Weaver
2018-08-26 22:08 ` Matt Wette
2018-08-27 8:04 ` tomas
2018-08-27 20:12 ` Mark H Weaver
2018-08-27 20:46 ` Mark H Weaver
2018-08-28 0:50 ` Matt Wette
2018-08-28 6:58 ` Mark H Weaver
2018-08-28 15:19 ` John Cowan
2018-08-28 15:38 ` Mark H Weaver
2018-08-28 15:59 ` Mark H Weaver
2018-08-28 16:12 ` John Cowan
2018-08-28 17:15 ` Mark H Weaver
2018-08-28 19:07 ` Mark H Weaver
2018-08-27 20:54 ` Hans Åberg
2018-08-27 0:17 ` Panicz Maciej Godek
2018-08-27 8:02 ` tomas
2018-08-27 8:29 ` Panicz Maciej Godek
2018-08-27 8:29 ` HiPhish
[not found] ` <8840615.kRvQfVdCvZ@aleksandar-ixtreme-m5740>
[not found] ` <CAD2gp_QLqd=_RbF=HTEbCLp1onmUq-c74g0FXTvMgdz8JB4-8A@mail.gmail.com>
2018-08-27 8:24 ` HiPhish
[not found] ` <3467110.H24gZIzStD@aleksandar-ixtreme-m5740>
[not found] ` <87ftz0vidc.fsf@netris.org>
2018-08-27 8:40 ` HiPhish
2018-08-27 12:37 ` Ludovic Courtès
2018-08-27 19:49 ` Mark H Weaver
2018-08-28 7:52 ` Ludovic Courtès [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-08-26 20:25 HiPhish
2018-09-13 21:49 HiPhish
[not found] ` <CAD2gp_Sg-aDXZKfOcL-i2py7ne4c0Cp+2HvKS4DYi1Antm_B1A@mail.gmail.com>
2018-09-14 22:45 ` HiPhish
2018-09-15 0:26 ` John Cowan
2018-09-15 14:50 ` HiPhish
2018-09-15 18:28 ` Keith Wright
2018-09-15 21:50 ` Edwin Watkeys
2018-09-15 22:16 ` HiPhish
2018-09-15 22:23 ` Edwin Watkeys
2018-09-15 22:13 ` HiPhish
2018-09-15 22:45 ` David Pirotte
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