bug#21391: 24.5; `thing-at-point' should return a string

[Eli Zaretskii]

> From: Andreas Röhler <andreas.roehler@easy-emacs.de>
> Date: Mon, 14 Nov 2016 11:26:54 +0100
> 
> IMHO the current design is really confusing and shouldn't be kept.

IMNSHO it would be madness to make incompatible changes 20 years after
the code was admitted into Emacs.

> if (get thing 'thing-at-point)
>               (funcall (get thing 'thing-at-point))
> 
> AFAIU an arbitrary function might  be stored here, no real relation to 
> thing-at-point at all.

Correct.  We have gobs of functions that can return several different
kinds of objects.

> Next clause deals with buffer-substring - which is thing-at-point about 
> in my understanding.

IMO, your understanding is wrong at least since 1997.