kitty + helix = felis

felis is the missing link between the helix editor and the kitty terminal: its purpose is to simplify the integration between this two software.

Commands

• open-file: opens a file in helix, by "typing" ESC + :open path/to/file + ENTER into the kitty window running helix.
• open-browser: runs the given file browser (e.g. broot), optionally in a kitty window overlay on top of helix, then opens the selected file.

Why is it useful?

Helix file explorer overlay

Running a file browser from helix gets as simple as this:

[keys.normal.space]
e = ":sh felis open-browser -l $(which broot)"

Notice that instead of just broot, the full path is used in this example, beause the program is going to run a kitty overlay, where the shell environment is not initialised, so PATHs might be missing (especially if you use home-manager).

To make this work, broot needs some configuration so that it prints the path and then exists when a file is selected:

[[verbs]]
apply_to = "file"
internal = ":print_path"
invocation = "print_path"
key = "enter"
leave_broot = true
shortcut = "pp"

Opening files from anywhere

Opening any selected file from kitty can be configured like this:

map ctrl+cmd+o pass_selection_to_program /path/to/felis/bin/felis open-file

This is particularly useful when another program, e.g. a test runner prints file paths to the standard output. Just select them with the mouse and open them in helix.

How is felis trying to find the right helix instance to open the file?

If the path is relative, felis will try to determine the absolute path: if it can find a focused and active window, then it's going to use this window's working directory. Once this is done, it is going to try to find a window which runs helix (../bin/hx) and where the working directory is the same or the parent of the file's directory (it doesn't have to be direct parent).

Let's see an example:

In window (1) the working directory is /path/to/felis, and helix is running. In window (2) the working directory is the same, and we run some tests (so it is the focused active window), and the output says there's an error in lib.rs on line 13, column 3. We select src/lib.rs:13:3, hit the key combination that will pass this to felis, which in the end will run felis open-file src/ lib.rs:13:3. Based on the active focused window felis will resolve the absolute path as /path/to/felis/src.lib.rs:13:3, it will find window (1) as it is running helix and its working directory is the parent of the file. Once this window is found felis will send the key sequence to open the file, and then it will focus the window.

Roadmap

• declaratively (probably via TOML) define tab/window layout as a project environment, with roles assigned to tabs/windows for easier scripting