Re: [External] : Re: command mode-specificity [was: scratch/command 064f146 1/2: Change...]

[Óscar Fuentes]

Alan Mackenzie <acm@muc.de> writes:

> Hello, Robert.
>
> On Thu, Feb 18, 2021 at 18:55:59 +0100, Robert Pluim wrote:
>> >>>>> On Thu, 18 Feb 2021 17:35:44 +0000, Alan Mackenzie <acm@muc.de> said:
>
>>     Alan> No, not from some other mode.  We're talking about commands shared 
>> by a
>>     Alan> set of modes known only at runtime.  If the list of modes cannot be
>>     Alan> updated at runtime, this is a deficiency in the design.
>
>> Iʼm having a hard time thinking of an example, eg you might not know
>> which of the modes provided by the cc-mode package the user actually
>> uses, but adding all of them to the relevant commands can be done
>> beforehand. Can you expand?
>
> No, it can't be done.  There is no list of "all" CC Mode packages.
> They're largely created and distributed by third parties, i.e. they're
> outside the orbit of Emacs development.  There is no complete list of
> them.

AFAIR those modes derive from c-mode, right? It that is so, the commands
are automatically applicable to them.

> For this facility to be general, the list of modes MUST be changeable at
> runtime.

Why at runtime? (apart that compile-time and run-time is a somewhat
diffuse distinction for Elisp) Can't the mode have declarations like
thos I mentioned?

But apart from that, I see no big problem about changing the list of
modes at runtime, although I don't know the current implementation, so I
hope someone else can clarify this.