coroutine create & resume

Now that you understand what coroutines are, let's learn how to actually create and run them in Lua.

To create a coroutine, you use the coroutine.create() function. This function takes a regular function as its argument and wraps it into a coroutine object. Here's the basic syntax:

function myTask()
    print("Hello from coroutine!")
end

local co = coroutine.create(myTask)

At this point, the coroutine exists but hasn't started running yet. The function myTask hasn't been called. To actually start or continue a coroutine's execution, you use coroutine.resume():

coroutine.resume(co)

When you call resume() on a coroutine for the first time, it starts executing from the beginning of its function. If the coroutine runs all the way through without pausing, it completes and cannot be resumed again.

Here's a complete example:

function greet()
    print("Starting...")
    print("Finishing!")
end

local co = coroutine.create(greet)
coroutine.resume(co)  -- Prints both messages

The coroutine runs from start to finish in one go. In the next lesson, you'll learn how to make coroutines pause in the middle of execution.