awesome/tests/examples/text/gears/object/signal.lua

local gears = require("gears") --DOC_HIDE

local o = gears.object{}

 -- Function can be attached to signals
local function slot(obj, a, b, c)
    print("In slot", obj, a, b, c)
end

o:connect_signal("my_signal", slot)

 -- Emitting can be done without arguments. In that case, the object will be
 -- implicitly added as an argument.
o:emit_signal "my_signal"

 -- It is also possible to add as many random arguments are required.
o:emit_signal("my_signal", "foo", "bar", 42)

 -- Finally, to allow the object to be garbage collected (the memory freed), it
 -- is necessary to disconnect the signal or use `weak_connect_signal`
o:disconnect_signal("my_signal", slot)

 -- This time, the `slot` wont be called as it is no longer connected.
o:emit_signal "my_signal"