Re: [boost] [coroutine] new versions

Subject: Re: [boost] [coroutine] new versions
From: Oliver Kowalke (oliver.kowalke_at_[hidden])
Date: 2012-10-11 05:22:48

-------- Original-Nachricht --------
> Datum: Thu, 11 Oct 2012 08:20:38 +0200
> Von: "Oliver Kowalke" <oliver.kowalke_at_[hidden]>
> An: boost_at_[hidden], boost_at_[hidden]
> Betreff: Re: [boost] [coroutine] new versions

> > I would
> > like to see the coroutine-function with a void return type. Or have an
> > option for that.
> 
> I've had such a version but I dropped it because for detecting the
> completeness of the coroutine would require an extra jump (return from last
> jump-function and calling return in the coroutine-fn).
> And this makes the implementation for iterators very painful:
> 
> void fn( coroutine<void(int)> & c) {
>     c( 1);
>     c( 2);
> }
> 
> The iterator would be required to be incremented three times. And
> std::distance would return 3 instead of 2.

If coroutine-fn is required to return void - we could detect the last 'caller_t::operator()' from coroutine-fn if we require to test the coroutine after each call:

typedef coroutine< int() >     coro1_t;
typedef coroutine< void(int) > coro2_t;

void fn( coro2_t & c) {
   c( 1);
   c( 2);
}

coro1_t c( fn);
while ( c) {
   c();
   if ( ! c) break;
   int res = c.get();
}

Oliver