Re: Input for TTY menus

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: emacs-devel@gnu.org
> Date: Thu, 19 Sep 2013 15:21:17 -0400
> 
> >> read_char won't handle the arrow keys.  To handle the arrow keys you
> >> need to use read_key_sequence
> > Thanks.  This means I'll probably need to clone some small subset of
> > the code in command_loop_1 after it calls read_key_sequence, in order
> > to process the key sequence, right?
> 
> I don't think there's much to do there, but clearly you'll want to do
> something with the sequence, indeed.  Although you might like to simply
> setup your keymaps in such a way that you can just use
> read_key_sequence_cmd (which should usually be the same as (key-binding
> <keys>), except when the keymaps are dynamic and might change between
> the time they were read by read_key_sequence and the call to
> key-binding) to know what operation to perform.
> 
> >> (probably after setting up some overriding-terminal-local-map).
> > What would be the purpose of overriding-terminal-local-map in this
> > case?
> 
> The key sequences read by read_key_sequence depend on the currently
> active keymaps to decide when a key sequence is complete (i.e. when to
> stop reading subsequent events).

Is it OK to bind keys in overriding-terminal-local-map to symbols
whose function cell is void?  (The C code interprets these symbols
when they are delivered by read_key_sequence via
read_key_sequence_cmd.)  It seems to work, but I wonder if that is
just be sheer luck, and should be discouraged for some reason.