Lua编程示例（八）：生产者-消费者问题
发布于 2016-01-26 06:44:12 | 106 次阅读 | 评论: 0 | 来源: 网友投递
Lua 脚本语言
Lua 是一个小巧的脚本语言。是巴西里约热内卢天主教大学（Pontifical Catholic University of Rio de Janeiro）里的一个研究小组，由Roberto Ierusalimschy、Waldemar Celes 和 Luiz Henrique de Figueiredo所组成并于1993年开发。 其设计目的是为了嵌入应用程序中，从而为应用程序提供灵活的扩展和定制功能。Lua由标准C编写而成，几乎在所有操作系统和平台上都可以编译，运行。Lua并没有提供强大的库，这是由它的定位决定的。所以Lua不适合作为开发独立应用程序的语言。Lua 有一个同时进行的GIT项目，提供在特定平台上的即时编译功能。
这篇文章主要介绍了Lua编程示例（八）：生产者-消费者问题,本文直接给出实例代码,需要的朋友可以参考下
这个问题是比较经典的啦，基本所有语言的多线程都会涉及到，但是没想到Lua的这个这么复杂 抓狂
看了好长时间才算看明白，先上个逻辑图：
开始时调用消费者，当消费者需要值时，再调用生产者生产值，生产者生产值后停止，直到消费者再次请求。设计为消费者驱动的设计。
图画的不太好，可以先将Filter遮住，它是过滤器对两个程序之间传递的信息进行处理。去掉Filter逻辑就更清晰些了，就是两个“线程”（其实是两个协同程序）互相调用。resume回到yield处开始，支持嵌套，返回到栈顶的yield位置。yield是非阻塞的“线程同步”。这到有点像linux里的管道通信。
function receive(prod)
print("receive is called")
local status,value = coroutine.resume(prod)
return value
end
function send(x,prod)
print("send is called")
return coroutine.yield(x)
end
function producer()
return coroutine.create(function ()
print("producer is called")
while true do
print("producer run again")
local x = io.read()
send(x)
end
end)
end
function filter(prod)
return coroutine.create(function ()
for line = 1,1000 do
print("enter fliter "..line)
local x = receive(prod)
print("receive in filter finished")
x= string.format("%5d %s",line,x)
send(x,prod)
end
end)
end
function consumer(prod)
print("consumer is called")
while true do
print("consumer run again")
local x = receive(prod)
print("retrun customer")
io.write(x,"\n")
end
end
p = producer()
f=filter(p)
consumer(f)
运行结果：
consumer is called
consumer run again
receive is called
enter fliter 1
receive is called
producer is called
producer run again
fsy
send is called
receive in filter finished
send is called
retrun customer
1 fsy
consumer run again
receive is called
enter fliter 2
receive is called
producer run again
gaga
send is called
receive in filter finished
send is called
retrun customer
2 gaga
consumer run again
receive is called
enter fliter 3
receive is called
producer run again
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