On Tue, Jul 15, 2008 at 7:53 PM, Joel de Guzman <joel@boost-consulting.com> wrote:
1) The concept of an infinite-sequence.
I'm not quite happy that all sequences has a finite size. Perhaps we can return something like fusion::infinite_size
That would be really nice! I will make the Size template parameter a typename, so fusion::infinite_size can be specified if/when it becomes supported. I think the implementation will only need to change its behavior related to the end iterator. That way, we can have both finite and infinite lazy_sequences.
If this is possible, then we should have a new infinite-sequence concept. I wonder where and how that will fit in the fusion concepts hierarchy.
It seems orthogonal to other Sequence concepts... Maybe the Sequence concept should have the "size is an integral constant" requirement pulled out of it, and then have FiniteSequence and InfiniteSequence concepts that refine that?
2) If this is not possible, then the interface should at least be compatible with the at_c and at interfaces:
make_lazy_sequence<MPL-N>(f); make_lazy_sequence_c<N>(f);
and of course, its result_of counterparts.
OK
Then, oh well... docs. Where should we put this? views, I guess.
I had thought of it as a container, but I think you are right - should be a view. It is conceptually similar to single_view (in that it is not a view into a Sequence), perhaps described as "a view into the return values of a unary callabale object or function". That maybe suggests changing the name to something like "callable_view" (perhaps there is a better variant that doesn't suggest that the view is callable). Also - do you think we should support both unary and nullary callable entities (in the current naming convention, have both something like "lazy_sequence" and "uniform_lazy_sequence", or in the alternate naming convention, both "unary_callable_view" and "nullary_callable_view")? I started the docs at: http://www.dancinghacker.com/code/dataflow/dataflow/utility/lazy_sequence.ht... I will tease out the docs,tests,naming,directory location,etc. within the dataflow library sandbox until we have something that seems good. Best, Stjepan