From: "Andreas Röhler" <andreas.roehler@easy-emacs.de>
To: Drew Adams <drew.adams@oracle.com>,
Help Gnu Emacs mailing list <help-gnu-emacs@gnu.org>
Subject: Re: (copy-marker nil)
Date: Mon, 7 May 2018 19:16:54 +0200 [thread overview]
Message-ID: <34886144-0f66-5677-5054-b940cf0f6e76@easy-emacs.de> (raw)
In-Reply-To: <0cc6f5df-d980-492c-a6f3-86070a73488c@default>
On 07.05.2018 16:26, Drew Adams wrote:
>>> For most functions, passing nil for an &optional parameter is the same
>>> as omitting it.
>>> If MARKER is not specified, the new marker does not point anywhere.
>>
>> It's about the return value.
>> A marker pointing nowhere, might it be considered valid?
>
> What do you mean by "valid"? Yes, it's a marker. No, it
> doesn't have a buffer or position. The same is true of
> other Emacs-Lisp objects, such as overlays: they can exist
> without having non-nil values for certain of their properties.
>
>> Expected such returning nil.
>
> Why? The doc string is pretty clear that it returns a
> marker. And it is clear what happens if arg MARKER is
> nil: "the new marker does not point anywhere".
>
Is there a use-case for a marker pointing nowhere?
From my point of view refusing to create such a marker makes sense.
next prev parent reply other threads:[~2018-05-07 17:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 8:19 (copy-marker nil) Andreas Röhler
2018-05-07 13:39 ` John Mastro
2018-05-07 14:23 ` Andreas Röhler
2018-05-07 13:55 ` Noam Postavsky
2018-05-07 14:20 ` Andreas Röhler
2018-05-07 14:26 ` Drew Adams
2018-05-07 17:16 ` Andreas Röhler [this message]
2018-05-08 1:46 ` Stefan Monnier
2018-05-08 8:44 ` Andreas Röhler
2018-05-12 22:06 ` Stefan Monnier
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