bug#64046: 30.0.50; Quoting in customize choice tags

[Stephen Berman <stephen.berman@gmx.net>]

On Wed, 30 Aug 2023 12:29:47 -0300 Mauro Aranda <maurooaranda@gmail.com> wrote:

> Stephen Berman <stephen.berman@gmx.net> writes:
>
>> On Mon, 28 Aug 2023 11:33:09 +0200 Ola x Nilsson <ola.x.nilsson@axis.com>
>  wrote:
>>
>>> I agree that quote substition should be done on the car of simple item
>>> definitions.  I have no opinion on susbstitute-command-keys vs
>>> substitute-quotes.  But I came to think about the TITLE argument,
>>> shouldn't quote substition be performed on it as well?
>>
>> I think you're right about that as well, since the title is simply a
>> display feature.  AFAIK it wouldn't make a noticeable difference for
>> existing uses of widget-choose in the Customize UI (in the Value menu
>> the title is simply "Choice" and in the State menu it's "Operation on
>> <option name>"), but it might be relevant for third party uses or future
>> uses in Emacs, as well as for ad-hoc uses of simple item definitions.
>> So applying substition to all uses of TITLE seems appropriate.  The
>> below patch does this, and also corrects my previous patch by excluding
>> substition from the cdr of simple item definitions.
>
> What would be a real-life scenario where we need to use
> substitute-command-keys on TITLE? I can't think of any.

I can't think of a really convincing example where it's needed, but just
as a possibility for stylistic variation, e.g. for simple item
definitions one could have a more explicit prompt like this:

(widget-choose "Type `0' or `1'" '(("Use `a'" . "Use `1'") ("Use `b'" . "Use `2'")))

which would appear as "Type ‘0’ or ‘1’" with curve-style quotes.  For
the Customize UI, although the title is currently hard-coded as
"Choice", one could define a widget with a title like "User's choice",
which would appear as "User’s choice" with the curve-style quote.
Unless some undesirable consequence of applying substitute-command-keys
to TITLE is found, I don't see any harm in allowing such uses.

Steve Berman