multithreading - 为什么这个简单的Lua协程不起作用？

Question

我有一个非常简单的Lua小代码，是我在自学协程如何工作时编写的。

直到我接受coroutine.wrap之前，我还不错，spec指出:

coroutine.wrap (f)

Creates a new coroutine, with body f. f must be a Lua function. Returns a function that resumes the coroutine each time it is called. Any arguments passed to the function behave as the extra arguments to resume. Returns the same values returned by resume, except the first boolean. In case of error, propagates the error.

但是这段代码:

Enumeration = {}

Enumeration.Create = function(generator)
    return coroutine.wrap(generator, coroutine.yield)
end

local function TestEnumerator(yield)
    yield(1) --ERROR HERE
    yield(2)
    yield(3)
end

local enumerator = Enumeration.Create(TestEnumerator)
local first = enumerator()
local second = enumerator()
local third = enumerator()

print (first, second, third)

提示产量为零(在我上面标记的那一行上)。据我了解，yield应该是传递给coroutine.wrap的第二个参数，那么我哪里出错了？

真正显而易见的解决方案，这要归功于以下答案

Enumeration.Create = function(generator)
    local iter = coroutine.wrap(generator, coroutine.yield)
    return function()
        return iter(coroutine.yield)
    end
end

Answer 1

这不是coroutine.wrap的工作方式。您必须在第一次调用coroutine.yield时传递enumerator。