用Lua的协程实现类似Unity协程的语句块

local co_time_tbl = {}
setmetatable(co_time_tbl, { __len = function(o)
    local count = 0
    for k, v in pairs(o) do
        count = count + 1
    end
    return count
end
})

local function isWindows()
    return package.config:sub(1, 1) == "\"
end

local function sleep(n)
    if isWindows() then
        if n > 0 then
            os.execute("ping -n " .. tonumber(n + 1) .. " localhost > NUL")
        end
    else
        os.execute("sleep " .. tonumber(n))
    end
end

local function Update(deltaTime)
    -- main loop
end

local function updateCoroutine()
    local iTime = os.time()
    for kco, vTime in pairs(co_time_tbl) do
        if iTime >= vTime then
            if coroutine.status(kco) == "suspended" or coroutine.status(kco) == "normal" then
                coroutine.resume(kco)
            elseif coroutine.status(kco) == "dead" then
                co_time_tbl[kco] = nil
            end
        end
    end
end

function coroutine.waitforSeconds(second)
    assert(type(second) == "number" or second <= 0)
    local iEndTime = os.time() + second
    local co = coroutine.running()
    if co then
        co_time_tbl[co] = iEndTime
        return coroutine.yield()
    end
end

local function main()
    local co1 = coroutine.wrap(function()
        coroutine.waitforSeconds(5)
        print("after 5 seconds")
    end)
    local co2 = coroutine.wrap(function()
        coroutine.waitforSeconds(4)
        print("after 4 seconds")
    end)
    local co3 = coroutine.wrap(function()
        coroutine.waitforSeconds(3)
        print("after 3 seconds")
    end)
    local count = 0
    local co4 = coroutine.wrap(function()
        while (true) do
            coroutine.waitforSeconds(1)
            count = count + 1
            print("coroutine num: " .. #co_time_tbl .. " | second count:" .. count)
        end
    end)
    co1()
    co2()
    co3()
    co4()
    while true do
        sleep(0.033)
        Update()
        updateCoroutine()
    end
end

main()

思路其实就是用一张表维护协程要等待的时间，在主循环之后更新计时器，根据时间将挂起的协程唤醒就行