LXID (Lua X Input Daemon)

This is a minimal, performant and modular implementation of a hotkey daemon powered with Rust and Lua. I made it for myself to load and unload keyboard hotkeys more dynamically than sxhkd supports it. It also provides mouse support.

Installation

This project is still in development.

Build the base using cargo.

cd base
cargo build --release

To use the standard libraries, install them using the Makefile (Root privileges are needed).

make install-lib

Configuration

LXID needs to be started by a user with a home directory. The initialization file should be located at ~/.config/lxid/init.lua.

All Lua 5.4 features are supported. To get started, include lxid and initialize the features that will be used.

-- Beside keyboard, other available features are: click, move
local lxid = require"lxid".setup({keyboard = true})

This will initialize keyboard events. Add a new event listener using the insert function.

lxid:insert("keydown", function(key)
  print("Key pressed: " .. key)
end)

Key signals are numbers that consist out of a category and local id. To evaluate them more easily, use the lxid.key object.

local Key = require"lxid.key"

It is for example now possible to check if the A key on the keyboard was released.

lxid:insert("keyup", function(key)
  if key == Key.alpha"A" then -- Always use uppercase keys
    print("A Key was released")
  end
end)

It is also possible to filter events. This is useful if multiple keystates should be checked.

Use a Keymap to save the keystate of every key.

local keymap = require"lxid.keymap":new(lxid)

The keymap can now be used as an event extension. To create a new extended function include the event module.

local ev = require"event"

-- If meta+Enter are pressed, open a terminal
lxid:insert("keydown", ev.ext(function()
  os.execute("alacritty")
end, {
  -- Call the keyboard extension and then run the event
  -- if not canceled
  ext = {keymap:ext(), ev.run},
  -- Extension information
  fields = {
    -- Execute the function if meta+E are pressed
    keys = {Key.SuperLeft, Key.Return},
  },
}))

Use the remove extension if an event should only be executed once.

local ev = require"event"

lxid:insert("keydown", ev.ext(function(key)
  print("Key pressed: " .. key)
end), {ext = {ev.run, ev.rem}}) -- Run and then remove the listener

Events can also be unloaded externally.

local listener_id = lxid:insert("keydown", function(key)
end)

lxid:remove("keydown", listener_id)

It is also possible to create custom event handlers. This will for example merge the mousepress and keydown listener to one event.

local lxid = require"lxid".setup({keyboard = true, click = true})
local Key = require"lxid.key"
local ev = require"event"

-- Create a new event handler
local handler = ev.EventHandler:new()

-- Create a function that will refer to all registered listeners
local caller = handler:create_caller()

lxid:insert("keydown", caller)
lxid:insert("mousepress", caller)

handler:insert(function(key)
  -- Check if the key is in category mouse
  if Key.prefix(key) == Key.category.Mouse then
    print("Mousepress")
  else
    print("Keydown")
  end
end)

To create a collection of event handlers, use an event pool. lxid is also an instance of this object.

local ev = require"event"

local pool = ev.EventPool:new()
-- Create a new event handler with the name "event"
pool:create_namespace("event")
-- Get the event handler and create a caller function
local caller = pool:get_namespace("event"):create_caller()

pool:insert("event", function(message)
  print("Listener called with message: " .. message)
end)

caller("Hello World!")

Listener called with message: Hello World!

Every library (including lxid itself) is optional and can be changed/extended/replaced with another implementation in Lua.