I've speculated about using "fibers" in Win32 to implement iterators that can yeild. Calling the function in its own super-lightweight thread means it can keep its stack, so it doesn't need to return but can yeild and keep looping. I never wrote up that article (yet) though.

You can also do iterator, today, using objects. 

my $iterator= $container->iterate();
while (my $item= $iterator++) { process $$item; }

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The code behind ++ would have to save its state and return each time, so it's harder to write than having a yeild. But you declare the iterator instance and can use that one (or another one).

What if yeild caused the call to return a token, and that is what you make subsequent calls on? You can have another one going without conflict.

I agree that it doesn't sound like co-routines as described in classic literature. Those would "call" each other, rather than having a yeild statement at all. Such co-routines as members of the same object would also make sense.

—John

In reply to Re: Re (tilly) 1: Perl 6 coroutines (RFC 31) by John M. Dlugosz
in thread Perl 6 coroutines (RFC 31) by John M. Dlugosz

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