Re: master 3b41141708: Expose the name of an event's input device to Lisp

[Stefan Monnier]

Po Lu [2022-04-09 11:17:01] wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> We could put it in the "posn" thingy, but at the same time it's not
>> really a "posn" and it's kinda weird to duplicate it into the start and
>> the end posn of an event.  It would be better to associate it with the
>> event itself and have an `event-device` function to access it.
> But wouldn't that mean the `event-device' function would have to have a
> specific implementation for each kind of event, with different indexes
> passed to `nth', since we can only add information to the end of each
> event?

Not necessarily, it could be something like:

    (defun event-device (e)
      (when (consp e)
        (alist-get 'device (nthcdr 3 e))))

But I agree that the current representation of events is problematic.
We should make it more regular and self-descriptive, either based on an
alist as above or have every event come with some kind of "class" which
then describes the name&position of every accompanying data.


        Stefan