Re: [Emacs-diffs] master b75fb81 1/4: Extend button.el to take callback data

[Lars Ingebrigtsen <larsi@gnus.org>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>       (make-text-button start (point)
>> 			'face 'rcirc-url
>> 			'follow-link t
>> 			'burron-data url
>> 			'action #'browse-url)
>
> Odd.  I thought the benefit was for
>
>     (define-button-type 'my-type 'action #'browse-url)
>
>     [...]
>
>        (make-text-button start (point)
>                          'type 'my-type
>                          'burron-data url)
>
> where a closure is not an option.

Ah, yes, that seems useful.

> In this for the purpose of designing new APIs, we can take it for
> granted that lexical-scoping is available.  It's easy enough to convert
> an old package to use lexical-scoping.

In this case, I just wanted to rewrite some stuff to avoid using
widgets, which can be rather convoluted to reason about.  But it does
have callback values like this, so this brings button a feature to make
conversion easier.

But, yes, everything should be converted to lexical binding, and then
my example use case is much less of a thing.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no