Re: Suggested experimental test

[Dmitry Gutov]

On 26.03.2021 12:34, Stefan Kangas wrote:
> Dmitry Gutov <dgutov@yandex.ru> writes:
>
> > On 25.03.2021 23:11, Stefan Monnier wrote:
> > > E.g. if it's bound to `C-c` it's fairly convenient to have bindings
> > > within it of the form `C-<letter>`, but if it's bound to `c` instead
> > > (assuming a a modal key-binding scheme like vi) then using `C-<letter>`
> > > within it is much less convenient.
> >
> > Interesting example. I wanted to say nobody will bind it to 'c', but
> > some people might decide to bind it to M-c instead.
> >
> > Here's a thought: let's invent an extension of the kbd syntax which will
> > allow us to specify a modifier indirectly based on an entry in
> > key-translation-map. Like:
> >
> >     (kbd "<mode-specific> <mode-specific-modifier>-c")
> >
> > Even more backward-incompatible, but okay. But what to do if
> > <mode-specific> has no modifiers, like <menu> in Yuri's example?
> > Translate '<mode-specific-modifier>-c' to just 'c'? What happens to any
> > other simple 'c' entry in that keymap? Do we "flip" it to, say, 'C-c'?
>
> How about something like:
>
>      (mode-kbd "k")         ; C-c k
>      (mode-kbd "mod k")     ; C-c C-k
>      (mode-kbd "mod2 k")    ; C-c M-k
>      (mode-kbd "mod3 k")    ; C-c S-k
>
> Then mod, mod2 and mod3 could be set to use whatever modifier you want.
> And mode-kbd would use the correct prefix.

This looks nice and flexible, but probably doesn't address the essence 
of Stefan's complaint. Example:

If mode-specific-modifier is 'C-c', 'C-c C-k' seems like an easy-to-hit 
sequence, suitable for a frequently-used command.

If mode-specific-modifier is <menu> or <f2>, '<menu> C-k' is less easy 
to hit than '<menu> k', for example, and the latter binding might be 
preferable.

But the package author already has to make a choice between (mode-kbd 
"k") and (mode-kbd "mod k") for a given command without knowing 
mode-specific-modifier in advance.

> (BTW, it would be even nicer if we could evaluate such a form on
> key lookup.)

Yuri mentioned key-translation-map already. Perhaps it or a similar new 
mechanism could be employed.