Example for an added feature on beholder.lua (event can be stopped from propagating further on)

beholder_stopPropagation_example.lua

beholder = require("beholder")

print("stopObserving: callback is permanently removed")
function observer1()
    local id
    id = beholder.observe(
        'PLAYERDETECTION',
        function(x, y)
            print("observer1: player1 detected at", x, y)
            if x >= 5 then
                beholder.stopObserving(id)
            end
        end
    )
end

function observer2()
    local id
    id = beholder.observe(
        'PLAYERDETECTION',
        function(x, y)
            print("observer2: player1 detected at", x, y)
            if x >= 8 then
                beholder.stopObserving(id)
            end
        end
    )
end

observer1()
observer2()

for i = 1, 10 do
    beholder.trigger('PLAYERDETECTION', i, 200)
end
print("-----")
for i = 1, 10 do
    beholder.trigger('PLAYERDETECTION', i, 200)
end
beholder.reset()
print("\n##################\n")

print("stopPropagation: callback won't propagating *this* event further")
print("stopPropagation")
function observer1()
    local id
    id = beholder.observe(
        'PLAYERDETECTION',
        function(x, y)
            print("observer1: player1 detected at", x, y)
            if x >= 3 then
                beholder.stopPropagation(id)
            end
        end
    )
end
function observer2()
    local id
    id = beholder.observe(
        'PLAYERDETECTION',
        function(x, y)
            print("observer2: player1 detected at", x, y)
            if x >= 3 then
                beholder.stopPropagation(id)
            end
        end
    )
end

observer1()
observer2()

for i = 1, 10 do
    beholder.trigger('PLAYERDETECTION', i, 200)
end
print("-----")
for i = 1, 10 do
    beholder.trigger('PLAYERDETECTION', i, 200)
end