Lua 学习 chapter24

将协程用作迭代器

不断的resume来实现迭代。

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local function printResult(a)
    for i = 1, #a do
        io.write(a[i], " ")
    end
    io.write("n")
end
local function permgen(a,n)

n = n or #a

if n <= 1 then

coroutine.yield(a)

else

for i = 1, n do

a[n],a[i] = a[i],a[n]

permgen(a, n -1)

a[n],a[i] = a[i],a[n]

end

end

end
local function permutations(a)

local co = coroutine.create(function() permgen(a) end)

return function()

local code, res = coroutine.resume(co)

return res

end

end
for v in permutations({"a","b","c"}) do

printResult(v)

end

事件驱动式编程

假设我们有一个I/O库：

lib.runloop()：运行事件循环，在其中处理所有发生的事件并调用对应的回调函数。
lib.readline(steam,callback)：从指定流中读取一行，并在读取完成后带着读取的结果调用指定的回调函数
lib.writeline(stream,line,callback)：该函数写入一行
lib.stop():打破循环，用于程序结束

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local lib = {}
lib.readline = function(callback)
    print("等待输入：")
    lib.waitInput = true
    lib.callback = callback
end
lib.writeline = function(line,callback)
    io.write(line .. "from others")
    lib.waitWrite = true
    lib.callback = callback
end
lib.stop = function()

lib.flag = false

end
lib.runloop = function()

lib.flag = true

while lib.flag do

if lib.waitInput then

local line = io.read()

lib.waitInput = false

lib.callback(line)

elseif lib.waitWrite then

lib.waitWrite = false

lib.callback()

end

end

end

local function run (code)

local co = coroutine.wrap(function()

code()

lib.stop()

end)

co()

lib.runloop()

end
function putline(line)

local co = coroutine.running()

print(co)

local callback = (function() coroutine.resume(co) end)

lib.writeline(line,callback)

coroutine.yield()

end
function getline(line)

local co = coroutine.running()

print(co)

local callback = (function(l)

coroutine.resume(co,l)

end)

lib.readline(callback)

line = coroutine.yield()

return line

end
run(function ()

local t= {}

while true do

local line = getline()

if not line then

break

end

table.insert(t,line)

end

for i = #t, 1, - 1 do

putline(t[i] … "n")

end

end)

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Lua 学习 chapter24

目录

将协程用作迭代器

事件驱动式编程