From: Neil Jerram <neil@ossau.homelinux.net>
To: guile-user@gnu.org
Subject: Re: ?-suffix for booleans... good-idea? or bad-idea?
Date: Tue, 25 Apr 2017 19:08:33 +0100 [thread overview]
Message-ID: <abd857e1-0426-f76d-694a-90ac5786733a@ossau.homelinux.net> (raw)
In-Reply-To: <87inltgnj8.fsf@gmail.com>
I'm also not sure. In the past I've written code with an 'xxx?'
variable, and then added a procedure to set it, giving 'set-xxx?!' -
which is not exactly elegant.
Also I'm not sure it's best practice to have many
variables/attributes/parameters with boolean values, as this can lead to
code that has too many opaque uses of #t and #f. (I.e. it's often
unclear, at the point of use, what each #t or #f means.) It might be
better to refactor to something with non-boolean values, e.g. from
(set! red? #t)
(set! narrow?#t)
to
(set! properties '(red narrow))
And in that case the question about '?' would disappear.
Regards,
Neil
On 25/04/17 04:43, Alex Vong wrote:
> Good question! I can't decide as well. I want to know how people think
> about it.
>
> In a lazy language, a variable is a 0-ary thunk, while a predicate is a
> 1-ary thunk. Since they are really just special case of a general thing,
> it make sense to use foo? for both cases. But we all know guile is not
> lazy, so I really don't know what to do.
>
> Christopher Allan Webber <cwebber@dustycloud.org> writes:
>
>> Hello everyone! Here's a little bikeshed for us to paint.
>>
>> I've noticed that it's common in Guile modules to use "foo?" for
>> variable names involving booleans. It's tempting, because this looks
>> an awful lot like you're asking a question... and it's also common
>> for this even to be keyword arguments to procedures, etc.
>>
>> But is it a good idea? I thought "foo?" was supposed to be for
>> predicates, as a nicer version of the "foo-p" predicate convention in
>> other non-scheme lisps. I can't imagine other lisps doing "foo-p" for
>> just variables with boolean values.
>>
>> On the other hand, once you start adding ? to the end of boolean'y
>> things, it *does* become tempting to put them at the end of boolean
>> variables and arguments. It looks pretty nice.
>>
>> What do people think? I'm struggling with deciding what's the right
>> thing for my own code, but leaning towards "we shouldn't use the ?
>> suffix for just boolean values".
>>
>> - Chris
next prev parent reply other threads:[~2017-04-25 18:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-24 17:01 ?-suffix for booleans... good-idea? or bad-idea? Christopher Allan Webber
2017-04-25 3:43 ` Alex Vong
2017-04-25 15:50 ` Jan Wedekind
2017-04-25 16:21 ` Paul
2017-04-26 15:25 ` Alex Kost
2017-04-25 18:08 ` Neil Jerram [this message]
2017-04-25 16:53 ` Panicz Maciej Godek
2017-04-26 0:23 ` Thompson, David
2017-04-27 10:39 ` Jan Nieuwenhuizen
2017-04-27 10:53 ` Panicz Maciej Godek
2017-04-27 12:07 ` Marko Rauhamaa
2017-05-05 17:26 ` Vladimir Zhbanov
2017-05-05 19:44 ` szgyg
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