init.lua

function invertTable(t)
  local res = {}
  for k, v in pairs(t) do
    res[v] = k
  end
  return res
end

local capsMap = {
  -- Arrow keys
  i = { key = 'up' },
  k = { key = 'down' },
  j = { key = 'left' },
  l = { key = 'right' },

  -- Backtick and tilde
  escape = { key = '`' },

  -- Ctrl-B for tmux
  b = { mods = {'ctrl'} },
}

-- Other controls
capsMap['['] = { key = 'home' }
capsMap[']'] = { key = 'end' }
capsMap[';'] = { key = 'pageup' }
capsMap["'"] = { key = 'pagedown' }

local inverseKeycodes = invertTable(hs.keycodes.map)

local et = hs.eventtap.new({ hs.eventtap.event.types.keyDown }, function(event)
  local kc = event:getKeyCode()
  local mapped = capsMap[inverseKeycodes[kc]]
  
  if mapped ~= nil then
    if mapped.key ~= nil then event:setKeyCode(hs.keycodes.map[mapped.key]) end
    if mapped.mods ~= nil then
      local mods = event:getFlags()
      for _, m in pairs(mapped.mods) do
        mods[m] = true
      end
      event:setFlags(mods)
    end
    return true, {event}
  end

  return false
end)

-- Bind F13 to trigger the AnnePro CapsLock mode
function bindsAnne(mods)
  mods = mods or {}
  hs.hotkey.bind(
    mods,
    "F13",
    function () et:start() end,
    function () et:stop() end
  )
end

bindsAnne()
-- For ~
bindsAnne({'shift'})
-- For Cmd+`
bindsAnne({'cmd'})
-- For Cmd+Shift+Arrow
bindsAnne({'cmd', 'shift'})