--- Disonnect to a signal.
-- @tparam string name The name of the signal
-- @tparam function func The callback that should be disconnected
-- @function disconnect_signal

--- Emit a signal.
--
-- @tparam string name The name of the signal
-- @param ... Extra arguments for the callback functions. Each connected
--   function receives the object as first argument and then any extra arguments
--   that are given to emit_signal()
-- @function emit_signal

--- Connect to a signal.
-- @tparam string name The name of the signal
-- @tparam function func The callback to call when the signal is emitted
-- @function connect_signal

--- Connect to a signal weakly. This allows the callback function to be garbage
-- collected and automatically disconnects the signal when that happens.
--
-- **Warning:**
-- Only use this function if you really, really, really know what you
-- are doing.
-- @tparam string name The name of the signal
-- @tparam function func The callback to call when the signal is emitted
-- @function weak_connect_signal