async.lua

async.lua

local LOCALVERSION = 0

local async_mt = {}
local async = setmetatable({}, async_mt)
async.VERSION = LOCALVERSION

async.await = function(fn)
    return coroutine.yield(fn)
end

local function _pack(...)
    return table.pack and table.pack(...) or {n = select("#", ...), ...}
end
local function _unpack(dat, starts, ends)
    return (table.unpack or unpack)(dat, starts or 1, ends or dat.n)
end
local function _call(a, ...) return a(...) end

async_mt.__call = function(async, fn, retvals)
    local co = coroutine.create(fn)
    
    local function iterator(...)
        if (coroutine.status(co) == "suspended") then
            assert(type((...)) == "function", "need function in async.await")
            (...)(function(...) 
                local rets = _pack(coroutine.resume(co, ...))
                assert(rets[1], "failed to run code")
                iterator(_unpack(rets, 2)) 
            end)
        else
            retvals(...)
        end
    end
    local rets = _pack(coroutine.resume(co))
    assert(rets[1], "failed to run code")
    iterator(_unpack(rets, 2))
end

--[[
function fetch_db_data()
    return async.await(function(callback)
        -- async library code
        --  async_timer_callback(0.1, callback, "<error>")
        --  timer.Simple(0.1, function() callback "<error>" end)
    end)
end

async(function()
    return fetch_db_data(), fetch_db_data()
end, function(...)
    print(...)
end)
]]

return async

hi