[FEATURE] Allow keybind action value to be an array

[arkonger]

Scope checklist

• I read SCOPE.md and this request is not in the out of scope list.
• I am not requesting a new tiling layout or a new layout paradigm.
• I checked the documentation and examples/config.toml, and this is not already possible with configuration, window or layer rules, keybinds, submaps, or umbriel msg.
• This needs the compositor. A desktop shell, an ordinary client, or a script over umbriel msg cannot do it.
• I have searched existing issues and pull requests for the same request.
• I understand this can be closed as out of scope, and that this is a decision about the project, not about the idea.

Problem

I wanted to use notify-send to provide some visual feedback on layout/submap changes, so I wrote a couple of scripts for QoL -- but then I need to make my binding something like "Mod+W" = "spawn:bash -c 'umbriel msg workspace-set-layout:toggle && MY_SCRIPT'" to actually run the script on the keybinding. This I was happy with, but when I got to setting up the same thing for submaps, I realized I was better off using "submap[test],X" = bash -c 'umbriel msg ACTION && umbriel msg submap:reset && MY_SCRIPT' than using the built-in submap key for the binding.

What you already tried

I can definitely get the behavior I want if I essentially just write a bash script in my config, but I don't imagine I'm the only one who would want a feature like this & thought it was worth asking.

Area

Configuration

Proposed behavior

See this draft PR for a proof-of-concept. I think it is probably sufficient to keep the same behavior on the basic "BINDING" = "ACTION" syntax, but for the more advanced key-value syntax something like "BINDING" = { action = ["ACTION1", "ACTION2", ...], repeat = false, ... } could be nice & would really expand what is possible within configuration without falling back on external tools like bash.

Scope fit

As above, it's very possible now to get this behavior with e.g., a multi-line string embedding a bash script into the config; it simply feels clunky to me, and bloats the file size.

Prior art and references

In i3/sway, for instance, it's very possible to bind a series of commands to one keybinding using semicolons like so:

# Mark focused container for swap
bindsym $mod+Shift+m [con_mark="^swap-target$"] unmark "swap-target";\
  mark --add "swap-target";\
  exec notify-send -t 1500 "Marked for swap"
# Swap the containers
bindsym $mod+Shift+g swap container with mark "swap-target";\
  [con_mark="^swap-target$"] unmark "swap-target"

The apparent way to translate that concept to toml is by using an array of command strings.

Participation

• I am willing to implement this myself, after the scope is agreed.
• I can test an implementation in my own session.

Additional context

I'm happy to continue testing & refining my PR when I have free time, but I'm very open to suggestions on how to approach it / what would create the least friction for future maintenance.