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Identifying members
by coppro 14 Oct '08

14 Oct '08

In C++ it is possible to determine whether there exists a member of a class of a specified type (including member functions) with a given name. As far as I know, there exists no such functionality in Boost. Why is this? It can easily be implemented as a traits class for a specific identifier/signature, which can then be made into a macro.

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Merge permission sought
by Nicola Musatti 13 Oct '08

13 Oct '08

Hallo, I would like to merge the following changes from trunk to the release branch: http://svn.boost.org/trac/boost/attachment/ticket/2341/call_traits.patch http://svn.boost.org/trac/boost/attachment/ticket/2342/sp_convertible.patch http://svn.boost.org/trac/boost/attachment/ticket/2352/boost_filesystem.pat… http://svn.boost.org/trac/boost/attachment/ticket/2344/boost_iterator.patch They all relate to supporting the latest CodeGear (ex Borland) compiler and all went through at least one successful test cycle on trunk. May I go ahead? Is the merge procedure outlined here: http://svn.boost.org/trac/boost/wiki/ImprovingPractices#Mergingchangesfromd… still considered the correct one? Cheers, Nicola -- Nicola.Musatti <at> gmail <dot> com Home: http://nicola.musatti.googlepages.com/home Blog: http://wthwdik.wordpress.com/

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[filesystem]Setting permissions/chmod
by Johan Torp 13 Oct '08

13 Oct '08

After looking through boost.filesystem's documentation and code, I can't find anything about permissions. I assume boost.filesystem has not implemented this because it aims to be portable and POSIX style permissions isn't applicable on all operating systems. Am I correct? Best Regards, Johan Torp www.johantorp.com -- View this message in context: http://www.nabble.com/-filesystem-Setting-permissions-chmod-tp19950894p1995… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Geometry and spatial indexes, my opinion
by Mathias Gaunard 13 Oct '08

13 Oct '08

Hi, Wanting to code a simple 3D virtual world, I looked into the recent spatial indexes SOC work, which depends on the proposed geometry library. I have to admit I was fairly disappointed. So I'm going to put some critics, some quite harsh maybe, along with some ramblings about what I would have liked to have. Note that I am no geometry or space indexing expert, so what I say may be perfectly silly. For starters, I think those libraries should be dimension agnostic and generic. Geometry not only has a strong 2D bias, but the documentation also says geometry::box only works with point_xy (and point_ll). Since it is used everywhere in spatial index, that means it's unusable on 3D. The geometry documentation doesn't clearly state what a geometry::box is. Is it (assuming 2D) any rectangle or only axis-aligned rectangles? In case it is just any rectangle, it mind be interesting to introduce a new type for axis-aligned ones, which can always be defined from two points whatever the dimension (well, at least it seems enough for 3D, I'm not good at projecting in other dimensions to see if that'd work). I suppose the spatial index interface expects axis-aligned boxes, so it's fairly important to clarify what we're talking about. Apart from that, there is also lots of point_xy-dependent code in spatial indexes. Also the quadtree implementation isn't dimension agnostic in particular (it should have 2^n children nodes, and not 4). I don't really get why it uses shared_ptr everywhere either (is it supposed to support COW or something?) I don't really get what boost::spatial_index::spatial_index is for. It does nothing but forward everything to the last template parameter. Instead of writing boost::spatial_index::spatial_index< point_type, value_type, boost::spatial_index::rtree<point_type, value_type> > index(args...); I might as well write boost::spatial_index::rtree<point_type, value_type> index(args...); Also, I think the spatial indexes do not provide enough operations. The only things they allow is putting point => value pairs, retrieving the value associated to a point in O(log n) time (I assume, complexity is not documented), and finding all values within a certain box (in O(log n) too?). Many things one typically wants to do with spatial indexes are not possible: - Iterate all (points, value) pairs in the index - Find the element closest (or k-closest) to some point in space or other element. - Find all elements within a certain range of some point in space or other element - Find the elements that intersect with a given object (ray tracing, for example, searches for an element that intersects with a ray and that is the closest to its source) - Consider only a part of the indexed space (e.g. an area delimited by a range/sphere or box) - Being able to index arbitrary objects and not just points - Traverse the spatial index as a tree I believe there is no need to clutter the interface with a lot of functions, most algorithms can be implemented generically as free functions. Giving a read-only tree interface to all spatial indexes ought to be enough to implement all algorithms. A spatial index, after all (correct me if I'm wrong), is nothing else but a tree that partitions space, where every node defines a partition of space that includes all of its children (which might overlap or not). Subtrees should be full-fledged spatial indexes (so that I can perform a search in a subtree), albeit read-only. Apart from that they should allow insertion and removal of object => value pairs. Quadtrees and r-trees should be fairly easy to work with: they both partition space into axis-aligned boxes (which are even cubes in quadtrees). As for allowing all kinds of objects to be stored instead of just points, that should be possible by using generic distance and intersection functions. The real difference is that the same object could eventually be in multiple places in the tree, because it spans over multiple space partitions. Whenever you put an object in the tree or split a partition, however, it would be necessary to calculate in which partitions to put the object, whereas with points you only have to find the one partition. Of course, some cases can be specialized and optimized, like axis-aligned boxes in a R-tree, which can directly be used as partitions and thus never span across multiple ones. I find it weird having a different interface for R-trees and Quadtrees. Indeed, one can only put points in a quadtree while in a r-tree you can put boxes as well. A generic approach allowing to put any object with boxes specialized seems like a better approach to me. About geometry, I think there should be more basic objects. While it is true polygons and multipolygons (polyhedrons) are enough to represent everything in 3D space, having rays, segments, triangles, quads, circles, spheres, squares, rectangles, cubes, cuboids (boxes), planes, half-planes and more, with ability to compute all intersections and distances, would be the most practical thing for 3D development. I do not know how to organize this in a really dimension-agnostic manner, however. In a nutshell, I think the spatial indexes design and how geometry can help it ought to be discussed.

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[1.37.0] Release branch closed except by permission, beta one week from today
by Beman Dawes 13 Oct '08

13 Oct '08

The release branch is now closed for all changes except by permission from one of the release managers. The beta release is planned for one week from today. That's a three day schedule to provide a bit more time for QA reviews, and because it seems to work a bit better if target dates fall at the end of weekends rather than Fridays. --Beman

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[trac] add component "proto"
by Eric Niebler 13 Oct '08

13 Oct '08

If I'm able to add a component to Boost's trac, I don't know how. We need a component for Proto. Owner: eric_niebler/Eric Niebler. Description is below: "Expression template library and compiler construction toolkit for domain-specific embedded languages." Thanks, -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Re: [boost] [phoenix] Phoenix & 1.37
by Alp Mestan 12 Oct '08

12 Oct '08

Need some help for Phoenix ? On 10/8/08, Joel de Guzman <joel(a)boost-consulting.com> wrote: >> >> Robert Jones wrote: >> >>> I see the 1.37 release is gathering momentum. >>> >>> We will see any development of Phoenix in 1.37, following on from >>> all the input of the recent review? >>> >> >> There will be development, yes. But we're still a long way >> to go. There's no chance we can make it in time for 1.37. >> I don't think so. Sorry. There's a lot to do still and it's >> impossible to do them all in a short period of time. 1.38 >> (or 1.39?) is ~probably~ a good target. >> >> Regards, >> -- >> Joel de Guzman >> http://www.boostpro.com >> http://spirit.sf.net >> >> _______________________________________________ >> Unsubscribe & other changes: >> http://lists.boost.org/mailman/listinfo.cgi/boost >> > > > > -- > Alp Mestan > --- http://blog.mestan.fr/ > --- http://alp.developpez.com/ > --- In charge of the Qt, Algorithms and Artificial Intelligence sections on > Developpez -- Alp Mestan --- http://blog.mestan.fr/ --- http://alp.developpez.com/ --- In charge of the Qt, Algorithms and Artificial Intelligence sections on Developpez

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ARM thumb support in spinlock_gcc_arm.hpp
by Jerry Napoli 12 Oct '08

12 Oct '08

Hi, I'm trying to compile using boost 1_36_0 for ARMv6 Thumb for iPhone development. The compiler used is gcc 4.0.x supplied with the iphone sdk. I run into issues with the inline assembly inside boost/detail/spinlock_gcc_arm.hpp. It generates a SWP instruction which (AFAIK) is not supported in thumb mode. The gnu arm assembler gives me a 'bad instruction ...' error. I'm able to work around it by modifying spinlock.hpp to include spinlock_sp.hpp instead. But has anyone addressed spinlock support for armv6 thumb? Thanks, Jerry

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[iostreams] gzip.hpp has impl in header file: multiple definition errors
by troy d. straszheim 12 Oct '08

12 Oct '08

On the trunk, gzip.hpp contains definitions for gzip_footer and gzip_header. If you use these in more than one compilation unit you get multiple definition errors at link time. I have the fix ready to commit... -t

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[shared_ptr] Ticket 2126 status?
by Andrey Semashev 11 Oct '08

11 Oct '08

Hi, Is the ticket 2126: http://svn.boost.org/trac/boost/ticket/2126 actually fixed in trunk? The ticket is still open, but my code that uses enable_shared_from_this and make_shared runs fine on trunk. However, the issue is still present in the release branch. If the problem is actually fixed, and the fixture doesn't break anything else I'd like to ask to merge the change to the release branch. Thanks.

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