bug#39512: 28.0.50; Add command isearch-yank-region

[Ergus via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

On Tue, Aug 11, 2020 at 02:49:44AM +0300, Juri Linkov wrote:
>> Now I am using swiper which has an improved version for thing-at-point
>> (something like `thing-at-point-or-region` called `ivy-thing-at-point`)
>> which actually is much more useful and avoids an extra binding.
>>
>> https://github.com/abo-abo/swiper/blob/c6b60d34ac37bf4d91a25f16d22e528f85e06938/ivy.el#L426
>>
>> Implementing something like that in vanilla is (in my opinion) the best
>> default behaviors for isearch-forward-symbol-at-point. But I don't want
>> to go in that discussion in the mailing list because it is difficult to
>> get an agreement what touching old commands. But you are free to do it
>> if you want.
>
>Indeed there are two ways to add it: as a new command (that requires a new
>keybinding) or a new option (disabled by default) for the existing command.
>Maybe we could enable it by default, but I don't know how it will affect
>the use cases of users - maybe someone users use isearch to extend the
>active region to the next matching symbol, and don't want 'M-s .' to yank
>the region.

If the region is active but empty that functionality could make sense
(extend to the next thing at point), but when it is not empty I think it
doesn't make too much sense in general use... but let's wait for the
rest of the opinions.

Actually, probably such a function (thing-at-point-or-region) could be
added to thing-at-pt to use it in other functionalities too. (like
highlight thing at point, idle highlight thing at point or region, kill
thing at point or region and so on)

It is something I have seen re-implemented in many packages here and
there again and again, so probably it is time to provide it in vanilla.