main.lua

local text = display.newText({
    text = "Initial text",
    x = display.contentCenterX,
    y = display.contentCenterY,
})

transition.to(text, {
    y = display.contentCenterY * 0.2,
    time = 5000,
    iterations = -1,
    transition = easing.continuousLoop,
})

local doGood = true
local bigNumber = 122033000

if (doGood) then
    --------------------------------------
    --Good coroutine (no freeze)
    --------------------------------------
    local function coroutineFunc(maxI)
        local n, i = 1, 2

        while (i < maxI) do
            local steps = math.min(1000000, maxI - i + 1)
            for j = 1, steps do
                n = n * i / (i - 1)
                i = i + 1
            end
            coroutine.yield(i)
        end

        return n
    end

    local co = coroutine.create(coroutineFunc)
    local coStatus, newRes
    timer.performWithDelay(50, function(event)
        if coroutine.status(co) ~= "dead" then
            coStatus, newRes = coroutine.resume(co, bigNumber)
            print("resume", coStatus, newRes)
            text.text = "Processing " .. newRes
        else
            timer.cancel(event.source)
            print("cancel")
            text.text = text.text .. " Done!"
        end
    end, -1)
else
    --------------------------------------
    --Bad coroutine (freeze)
    --------------------------------------
    local function coroutineBadFunc(maxI)        
        local n = 1
        for i = 2, maxI do
            n = n * i / (i - 1)
        end
        
        return n
    end

    timer.performWithDelay(100, function()
        local co = coroutine.create(coroutineBadFunc)
        local coStatus, result = coroutine.resume(co, bigNumber)
        text.text = "Processing " .. result .. " Done!"
    end)
end