Keyboard macros you can type-check, diff, and hot reload

1One file, one macro

This is a complete script. Save it as dev-keys.luau, set REPO to one of your repositories, and start it with rebind run dev-keys.luau.

-- rebind: min_sdk=3.9.0 name=dev-keys version=1.0.0 permissions=exec

local REPO = (rb.env.home() or "") .. "/code/my-repo" -- your repository

-- Right Alt (Right Option on a Mac) becomes Escape
rb.bind.remap("RAlt", "Escape")

-- F5 logs git status for REPO without leaving the editor
rb.bind("F5", function()
  rb.run(function()
    local result = rb.system.exec("git status --short", { cwd = REPO, timeout = 10000 })
    if result.exit ~= 0 then
      rb.log.error(result.stderr)
    else
      rb.log.info(result.stdout)
    end
  end)
end)

The first line is the modeline: the script's name, its version, the oldest Rebind it runs on, and its permissions. It asks for exec and nothing else, so a network call from this script would be refused.

rb.bind.remap holds Escape for as long as Right Alt is down. rb.bind takes F5 and leaves every other key alone, and rb.run starts a coroutine so the command runs on a worker thread instead of holding up your input.

2The loop in four steps

1. Install Rebind

   Download Rebind, free on Windows and macOS. The standard install puts the rebind command on your path.

2. Give your editor the types

   In VS Code, add the Luau Language Server and point it at Rebind's definition file. Every rb call gets autocomplete, hover docs, and type checking.

3. Run it while you edit

   rebind run checks the script, loads it, and prints its log lines. Save a change and it checks and reloads. A failing check keeps the last good version running.

4. Poke at it

   rebind exec 'return rb.input.is_down("Shift")' runs one line inside Rebind. rebind logs streams every script's output, and rebind lint flags definite bugs such as a misspelled global.

3What a script can reach

All of these work the same on Windows and macOS. Screen, window, and app calls differ by platform; the SDK reference lists every call.

4What it won't do

• Change mouse movement without hardware. The free app remaps keys and buttons. Holding back or reshaping mouse movement needs hardware mode and a Rebind Link or BYOH.
• Tell two keyboards apart without hardware. Per-device binds and game controllers need hardware mode too.
• Stand in for rebind check. The language server checks types. rebind check also validates the modeline, the permissions, and every require.

5Other ways to script input

• AutoHotkey. Free, Windows only, its own language.
• Karabiner-Elements. Free, macOS only, rules written as JSON.
• Keyboard firmware such as QMK. Runs on the board itself, only on boards that support it, and changing its logic is a reflash.
• Rebind. Free, Windows and macOS, Luau with a typed SDK and a CLI.

6Questions