Re: Add -other-{window, frame} variants of project-prefix-map commands

[Juri Linkov]

>> Note also that the tension between parsing `C-x 4 FOO` as "lookup FOO in
>> `ctl-x-4-map` (or in `ofw-transient-map`)" and "lookup FOO in the normal
>> way", which is why in `ofw--set-prefix` we do:
>>
>>  ;; FIXME: Setup a transient map to reproduce the behavior of the `C-x 4/5'
>>  ;; prefix keys, but only do it in "regular" buffers.  In special buffers,
>>  ;; these extra bindings may be more annoying than anything, e.g. in Gnus's
>>  ;; summary buffer `a' open a new message buffer, so we'd want `C-x
>>  ;; 5 a' to open it in a new frame, but instead of calling
>>  ;; add-change-log-entry.
>
> The latter ("lookup FOO in the normal way") is handled now by `C-x 5 5 a`,

I meant that in Gnus's summary buffer `C-x 5 5 a` opens a new message buffer
in a new frame.

> Maybe even it could employ some heuristic to automatically deduce
> the transient map based on the existing `C-x` keymap.  For example,
> from `C-x p b` (project-switch-to-buffer) it could build a new key
> sequence `C-x 5 p b`, etc.  This could help to close bug#42210.

Unfortunately, it can automatically turn `C-x C-f` only into `C-x 5 C-f`,
not to `C-x 5 f`, so probably no such automatic translation is possible.