Can't bind key ctrl-backspace (regression)

[dorsiflexion]

Bug summary

Ctrl-Backspace seems to be impossible to use as a key binding. This is a regression as it was possible prior to version 4.0.

Steps to reproduce

1. Press alt+k, followed by ctrl+backspace.

Current behavior

The output is: backspace /input delete_previous_char

Expected behavior

The output is: ctrl-backspace /input delete_previous_char

Suggested solutions

?

Additional information

Alternatively:

/key bind ctrl-backspace /input delete_previous_word doesn't work either.

---

• WeeChat version: 4.0.1
• OS, distribution and version: Arch Linux
• Terminal: Alacritty 0.12.2
• Terminal multiplexer (screen/tmux/…/none):  none

[flashcode]

Hi,

This is intentional, but probably we're lacking some doc to explain how to do it.

In fact WeeChat can not reliably distinguish backspace from ctrl-backspace: both keys have different raw code, but WeeChat can not know which one is backspace and which one is ctrl-backspace.

Then one way to bind ctrl-backspace is to bind the raw key code, which could be ctrl-h (this one is ctrl-backspace for me):

/key bind ctrl-h /print ctrl-h

Then try to press backspace and ctrl-backspace, you should have a different behavior.

If not working, try:

/key bind ctrl-? /print ctrl-?

If working fine, I'll update /help key to mention this.

[trygveaa]

To add to that, the reason WeeChat can't know which of these keys is which is that in a terminal emulator, backspace and ctrl-backspace maps to the ctrl-h and ctrl-? keys. However, which maps to which depends on which terminal emulator you're using and the configuration of that terminal emulator. So when WeeChat receives ctrl-h or ctrl-? there's no way for it to know if it came from a backspace press or a ctrl-backspace press. For more details about this, see this discussion: https://comp.terminals.narkive.com/i3ywh6Rv/backspace-h-vs-linux-vs-terminfo

To figure out what your terminal emulator sends, you can run /debug key in WeeChat and press ctrl-backspace.

Technically, in some terminal emulators it is possible to reliably distinguish between these keys by enabling an alternate keyboard protocol. However, this is not something WeeChat supports.

[flashcode]

I propose to add this text in /help key:

For some keys you might need to use /debug key, that also displays
the raw key code that can be used as well (for example ctrl+backspace
could be ctrl-h or ctrl-?, depending on your terminal and other settings).

[dorsiflexion]

Binding ctrl-h works for me. Thanks a lot. 👌