Re: [boost] [fusion] segmented fusion 2.0

Subject: Re: [boost] [fusion] segmented fusion 2.0
From: Joel de Guzman (joel_at_[hidden])
Date: 2011-08-15 19:38:48

On 8/12/2011 9:46 AM, Eric Niebler wrote:

>> Sounds like a plan. If you have some initial sketch/notes that
>> you can share, I'd love to get in the same page with you and share
>> some effort to get this going asap.
> 
> Here's my thinking:
> 
> 1)
> support/ext_/is_segmented.hpp          => support/
> sequence/intrinsic/ext_/segments.hpp   => sequence/intrinsic/
> sequence/intrinsic/ext_/size_s.hpp     => sequence/intrinsic/detail/
> view/ext_/segmented_iterator.hpp       => iterator/
> view/ext_/segmented_iterator_range.hpp => view/iterator_range/detail/
> view/ext_/segmented_begin.hpp          => sequence/intrinsic/detail/
> view/ext_/segmented_end.hpp            => sequence/intrinsic/detail/
> view/ext_/segmented_fold_until.hpp     => support/
> 
> Various supporting implementation details make corresponding moves.
> 
> container/ext_/tree.hpp becomes part of the test suite. It is poorly
> designed and doesn't deserve to be part of Fusion proper.
> 
> 2) begin, end, size and empty dispatch to their segmented
> implementations by default.
> 
> 3) The existing segmented algorithms (find_s, find_if_s, fold_s,
> for_each_s) just get merged with their non-segmented equivalents.
> 
> 4) Wait for the dust to settle. Assuming all is looking good, try making
> joint_view segmented.
> 
> 5) Use segmented_fold_until to write segmented flavors of as many
> algorithms as possible.
> 
> I can do 1-3. 5 can be a team effort and can begin as soon as everything
> has found its rightful place.
> 
> A word about segmented_fold_until. You call it with a hierarchical data
> structure, an initial state and a function. It walks the hierarchical
> structure and calls a function with each non-segmented range, the
> current state, and the "context". The context is actually the path
> through the tree to reach the current leaf range. You can pass it to
> make_segmented_iterator to (duh!) create a segmented iterator. The
> function that you pass to segmented_fold_until must wrap its returned
> object in a fusion::result, which contains a compile-time boolean:
> continue the fold or break. The returned object is the new state.

Thanks, Eric. If I haven't said so already, I think this is a
very nice plan. I can definitely help out with 4 & 5.

One thing to note though is that the fusion-0x code will fall out
of sync once we go through this. I'm CC'ing Christopher.

It would be foolish to merge fusion-0x now, in the middle of
development, but I think that the 0x code should finally be
merged to main as soon as the dust settles (after 3). Then,
we can move to 4 and 5 with fusion-0x code in place.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://boost-spirit.com