Re: [boost] [coroutine] new versions

11 Oct 2012


      -------- Original-Nachricht --------
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Datum: Thu, 11 Oct 2012 08:20:38 +0200
Von: "Oliver Kowalke" <oliver.kowalke@gmx.de>
An: boost@lists.boost.org, boost@lists.boost.org
Betreff: Re: [boost] [coroutine] new versions
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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