[DagAgren]

It is not. Coroutines are a much more fundamental feature. They can be used to implement cooperative multitasking, and since that is such a common use case, they have gotten confused with the concept of cooperative multitasking.

Actual coroutines are a lot more flexible and interesting than just cooperative multitasking, though.

[_0ffh]

Erm, I'm pretty sure I can implement coroutines using cooperative multitasking. Also, the other way around. So I'd say they're equivalent in that sense.

[DagAgren]

Cooperative multitasking usually involves a scheduler. Coroutines are called explicitly, which you can't do through a scheduler.

[_0ffh]

Now you're really just making claims about implementation details. That doesn't make one concept more "fundamental" or "flexible" than the other, while "interesting" is just a subjective judgement.

[DagAgren]

I'm not. The scheduler decides what code to execute next, the caller does not. With coroutines, the caller explicitly decides what code to execute next. That's a fundamental difference.

[_0ffh]

Explicitly selecting what code to execute next can be trivially achieved in a cooperative multitasking system. Naturally, the details work out differently. That's because both concepts are equivalent, just not the same.

[DagAgren]

Sure, you could implement some kind of anti-scheduler, but that is just plain silly, and really doesn't affect the point at all. You can do anything in any Turing-complete language, but that doesn't mean that Brainfuck is equivalent to Prolog in any way that is actually useful or interesting.

[TeMPOraL]

With coroutines, your program logic itself is the scheduler.

[DagAgren]

Thus why coroutines are more fundamental and powerful.