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

[Po Lu]

Brian Cully <bjc@spork.org> writes:

>       But my input driver is, for instance, a USB HID driver, and only
> cares about the usage tables my device is using. I can plug whatever
> device I want in, regardless of any kind of unique or stable identifier,
> by virtue of it responding correctly to probes from the USB layer
> describing its capabilities. Everything built on top of this stack Just
> Works, no matter how I name the device.

Then the input driver will set the right properties depending on which
events are currently being sent, and Emacs will also take into account
which events are being generated to decide how it behaves.

>       I see very much the value in being able to differentiate similar
> or identical events based on their source, but my worry has been about
> having Emacs somehow decide for me that because my device is named “X”
> it has capabilities w, y, and z.

No, Lisp code will decide based on the class of your device (on X,
that's calculated based on the name) _and_ the events it is currently
generating that it has capabilities x, y and z.

>       In a previous email, it seems as though your thoughts are around
> having the user specify capabilities or event mappings themselves based
> on the device name. I don’t know nearly enough about the specifics to
> comment on any particular approach, but I am reasonably sure I don’t
> want Emacs making those decisions for me.

That was specifically referring to user customisations.

Either way, I severely doubt this is a real problem, since such a device
would be fairly useless if it couldn't work with other programs such as
Firefox, LibreOffice, etc.