Re: [boost] Coroutines and Output Iterators

Subject: Re: [boost] Coroutines and Output Iterators
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2008-10-10 18:35:28

> > What I propose is thus to make an output iterator that will yield the
> data
> > within a coroutine context.
> > With that solution, one writes generators as functions writing to
> output
> > iterators, but those iterators might as well be writing to containers
> than
> > actually yielding the result, which means the person designing the
> generator
> > does not have the overhead of coroutines forced upon him.
> >
> <SNIP>
> 
> In fact I have been planning for a long time to make the 'self' type
> be a functor. The interface to yield a value would change from the
> current:
> 
> template<Self>
> my_result my_gen(Self& f) {
>    for(....)
>        self.yield(val);
>    self.exit();
> }
> 
> to:
> 
> template<F>
> void my_gen(F f) {
>     for(...)
>         f(val);
> }
> 
> (note the switch from pass by reference to pass by value)
> Making an output iterator from 'f' is trivial via
> boost::function_output_iterator.

This isn't such a good idea, IMHO. I'm using the GSoC version for quite some time now and this Self instance is a good place to store/access fiber specific data (similar to thread specific storage, but not has no thread affinity, i.e. is available regardless of which thread actually executes the fiber/coroutine).

Just my 2€c.
Regards Hartmut