On Sat, Jun 08, 2019 at 10:54:17PM +0900, Jean-Christophe Helary wrote:
> 
> 
> > On Jun 8, 2019, at 22:30, Eli Zaretskii <eliz@gnu.org> wrote:
> > 
> > We have an enormously complex piece of software on
> > our hands, and we have no better choice than going the "inconvenient"
> > ways when we want to rebind an unusual key.
> 
> In all honesty:
> 
> (define-key input-decode-map "\C-[" [C-left-bracket])
> (define-key global-map [C-left-bracket] 'myfunction)
> 
> is not inconvenient at all. What is inconvenient is the discovery process.

Then documentation is the way forward, perhaps?

> Knowing what I know about emacs (which is above the casual user) and even with the willingness to go through the manual, it would have been (it *has* been) impossible for me to find that solution.
> 
> Now, what I'd love to know is what are the other "unusual" keys, because as a group, they deserve a few more lines in the manual.

A good set of candidates would be all those control characters
(the first 31 in man ascii(7)) which are customarily bound
to a key (like CTRL-C, aka ETX, CTRL-\, aka FS, and so on).

Care to compile a list?

Cheers
-- tomás