Helix as external editor for Godot (using Zellij)

Helix as external editor for Godot (using Zellij)

# 
Setup using zellij with helix and lazygit to develop for Godot.
The hx.fish script is specific to my setup and will require alteration unless you already happen to be using i3, fish shell and xfce4-terminal

Since Helix doesn't support a client/server model that would allow us to open buffers in an existing session, zellij is used.
This also lets me use lazygit from within zellij as a floating pane, and have terminals.

Download and alter the hx.fish script to fit your setup (this may be somewhat difficult depending on what tools you use.
Most of the script exists to ensure that everything opens within the same terminal/zellij session, and that files are opened as buffers in the same helix process.
The allows me to open files from the godot editor directly without creating a new window each time.

In Godot, set the external editor path as:
  /path/to/hx.fish
And the exec flags to:
  {file}:{line}:{col} {project}
  
The provided zellix.kdl file is my default layout for zellij + helix. It has a main panel for helix, and two terminal windows.
It will also open lazygit in a floating panel when ALT+G is pressed, even when zellix itself is locked.

The Godot LSP setup is as per https://github.com/helix-editor/helix/wiki/Language-Server-Configurations#gdscript, but I also use "simple-completion-language-server" https://github.com/estin/simple-completion-language-server to support snippets and work completion.
My languages.toml is included as well.

hx.fish

#!/usr/bin/env fish

set session helix
set tab Helix
set window_name zellix
# Get the existing window of our session
set window (i3-msg -t get_tree | jq 'recurse(.nodes[]) | select(.window != null and .window_properties.title == "$window_name")')

function new_term_session -d "Creates a new terminal instance running zellij"
    xfce4-terminal -T "$window_name" -x zellij -s "$session"
end

function get_helix_info -d "Checks if a zellij session is running helix"
    echo (for p in (pgrep -x helix); pstree -s $p | grep zellij; end)
end

if test -z "$argv[1]"
    echo "No file provided"
    exit 1
end

# Move into our target directory
if not test -z "$argv[2]"
    echo "Switching to $argv[2]"
    cd "$argv[2]"
    # zellij -s "$session" run -- cd "$argv[2]"
end


# Open Zellij in a new terminal session
if test -z (zellij ls | grep "$session")
    echo "Starting session $session"
    new_term_session
else if not test -z (zellij ls | grep "$session" | grep "DEAD")
    echo "Attaching to existing (dead) session"
    new_term_session
else if not test -z (zellij ls | grep "$session" | grep "EXITED")
    echo "Killing and starting new session"
    zellij d "$session"
    sleep 0.5
    new_term_session
else if test -z "$window"
    echo "Attaching to existing (windowless) session"
    new_term_session
else
    echo "Session exists, opening file $argv[1]"
end

# Go to the helix tab, creating it if needed.
zellij -s "$session" action go-to-tab-name "$tab" --create
sleep 0.5

# Open helix if not already running
if test -z (for p in (pgrep -x helix); pstree -s $p | grep zellij; end)
    echo "Opening helix"
    zellij -s "$session" action write-chars "helix $argv[1]" # Do this instead of 'zellij run' so we stay in the helix pane
    zellij -s "$session" action write 13 # ENTER
else # Otherwise open the file
    echo "Using existing helix"
    zellij -s "$session" action write 27 # ESC
    zellij -s "$session" action write-chars ":open $argv[1]"
    zellij -s "$session" action write 13 # ENTER
end

languages.toml

# introduce new language server
[language-server.scls]
command = "simple-completion-language-server"

[language-server.scls.config]
max_completion_items = 20            # set max completion results len for each group: words, snippets, unicode-input
snippets_first = true                # completions will return before snippets by default
snippets_inline_by_word_tail = false # suggest snippets by WORD tail, for example text `xsq|` become `x^2|` when snippet `sq` has body `^2`
feature_words = true                 # enable completion by word
feature_snippets = true              # enable snippets
feature_unicode_input = true         # enable "unicode input"
feature_paths = true                 # enable path completion
feature_citations = false            # enable citation completion (only on `citation` feature enabled)


# write logs to /tmp/completion.log
[language-server.scls.environment]
RUST_LOG = "info,simple-completion-language-server=info"
LOG_FILE = "/tmp/completion.log"


[language-server.godot]
command = "nc" # or nc
args = [ "127.0.0.1", "6005"]

[[language]]
name = "gdscript"
language-servers = ["godot", "scls"] 

zellix.kdl

layout {
	tab name="Helix" {
    	pane size=1 borderless=true {
        	plugin location="zellij:tab-bar"
	    }
    	pane {
    		name "helix"
	        command "helix"
    	    args "."
	    }
	    pane split_direction="vertical" size="20%" {
    		pane {
    			name "terminal"
	    	}
	    	pane {
    			name "terminal2"
	    	}
	    } 
	    pane size=2 borderless=true {
    	    plugin location="zellij:status-bar"
	    }
	}
}
keybinds {
	shared {
		bind "Alt g" {
 			Run "lazygit"  {
 				x: "12%";
 				y: "12%";
 				width "75%";
 				height "75%";
	    	    close_on_exit true;
	    	};
		    TogglePaneEmbedOrFloating;
		}
	}
}

ui {
    pane_frames {
        rounded_corners true
    }
}