dmg-window-switch.lua

windowKeys = {}

function wkeys_prompt_for_key()
  local w = hs.window.focusedWindow()
  local result = nil
  hs.application.get("Hammerspoon"):activate()
  local button, text = hs.dialog.textPrompt("Input number key", "Please enter a single numeric character:", "", "OK", "Cancel")

  if button == "OK" then
    result =  text
  end
  if w then
    w:focus()
  end
  return result
end

function wkeys_attach_current_window_to_key()
  local w = hs.window.focusedWindow()
  if (w)  then
    local key = wkeys_prompt_for_key()
    if key and tonumber(key) then
      print(string.format("key [%s]", key))
      dmg_alert(string.format("attach key [%s] to window [%s]", key, w:title()))
      hs.hotkey.bind(
        {'alt'}, key,
        function () w:focus() end)
    else
      dmg_alert(string.format("Illegal key to attach a window [%s]", key))
    end
  end
end

hs.hotkey.bind(
  {'alt'}, '0',
  function () wkeys_attach_current_window_to_key() end)