On 8/11/2011 5:58 PM, Joel de Guzman wrote:
On 8/12/2011 8:37 AM, Eric Niebler wrote:
That's what I referred to by "baking it in". I imagine that all the ext_ directories go away, and segmentation support just becomes a native part of Fusion. These things would need to change:
- We find a new home for segmented_iterator.hpp et. al. - Sequence intrinsics (begin, end, size, empty) have meaningful default implementations for segmented data structures. - As many algorithms as possible should dispatch to segmented flavors when appropriate. E.g., ext_/fold_s.hpp just gets merged into fold.hpp. - Fusion containers and views that are segmented (joint_view) advertize themselves as such, and the rest of their implementation goes away.
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. -- Eric Niebler BoostPro Computing http://www.boostpro.com