Re: Ctrl-[ ?

[Clément Pit-Claudel]

On 2019-06-06 09:01, Eli Zaretskii wrote:
>> From: Mattias Engdegård <address@hidden>
>> Date: Thu, 6 Jun 2019 14:44:31 +0200
>> Cc: Emacs developers <address@hidden>,
>>         Jean-Christophe Helary <address@hidden>
>>
>> 6 juni 2019 kl. 12.12 skrev Eli Zaretskii <address@hidden>:
>>>
>>> It isn't hardcoded in Emacs, it' "hardcoded" in the way the OS produces 
>>> character codes when you type keys on the keyboard.  C-[ produces ESC for 
>>> the same reason C-i produces TAB and C-j produces RET: these keys emit the 
>>> same codes as the corresponding Ctrl sequences.
>>
>> The above is true when Emacs is running in a terminal. Otherwise, Emacs has 
>> code to emulate that behaviour (make_ctrl_char), so that we can enjoy a 
>> whiff of early 1960s bit-paired keyboards. And this does appear to be 
>> hard-coded, in the sense that it cannot be disabled.
> 
> Why is it useful to have different behavior on GUI and TTY frames?

It's not so much that it's useful to have different behavior; rather, there are 
limitations that only TTY frames suffer from, and if you mostly or always use 
GUI frames, it's nice not to suffer from these limitations.

For example in my day to day work I use variable-pitch faces, different font 
sizes, highlighting in ore colors than my terminal can display, svg support, 
and, most relevant to the discussion above, keybindings that gnome-terminal 
doesn't support, such as C-S-> and C-S-< (the location of these keys was 
convenient, and I knew I wouldn't need the corresponding functions often in TTY 
frames).

So I guess keeping a consistent experience in TTY and GUI frames isn't as 
important for me as improving the experience in GUI frames.

(I'm not claiming that Enacs' defaults should diverge between TTY and GUI; just 
that there are use cases for different behavior on GUI and TTY frames)