January 2008 - Boost - lists.boost.org

Re: [boost] [review] Fast track review of Boost.Utility/Singleton
by Tobias Schwinger 16 Jan '08

16 Jan '08

Nat, thanks for your very positive review. Nat Goodspeed wrote: > John Torjo wrote: > >> Today starts the formal Fast-Track review of the Boost.Utility/Singleton >> library. >> >> What to include in Review Comments >> ================================== >> >> Here are some questions you might want to answer in your review: >> >> * What is your evaluation of the design? > > Very strong. I like it! > I've implemented CRTP Singleton templates a few times before -- > highlighting the need for a Boost library. ;-) I'm pleased with the > deluxe functionality: >> * What is your evaluation of the documentation? > > Very clear, though not entirely complete, as described below. The > organization and style is excellent, and when polished, this > documentation will be exemplary. I like the examples. Pointing out the > ability to bind() instance and/or lease, and the semantics of each, is > great. Also the multiple-inheritance example to graft Singleton behavior > onto an existing class. > I didn't fully understand the thrust of the example described as: "We > might as well have a static facility use the Singleton internally, by > using non-public inheritance". A few more words about that example would > be useful; maybe a bit of the implementation of static void message(). I might have kept it so brief since I'm not too sure it's good practice. I think I'll better just remove it. > It appears that the third template parameter SubsystemTag was a > recent introduction. The documentation (especially the reference > material) doesn't describe it enough, and often fails to mention it > entirely. Yes. > The first paragraph under > http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_… > seems to want to be a bullet list that got flowed instead. Yes. > Very little is said about BOOST_SINGLETON_PLACEMENT and > BOOST_SINGLETON_PLACEMENT_DECLARATION. The reference material mentions > them without any explanation. That "Singletons and dynamic libraries" section explains their purpose. What exactly is missing? I'm not too fond of specifying what those macros expand to and I don't really want to mention them in the introductory section either, as for me they are kind-of workarounds for the imperfect ABIs we have to deal with. > The example > http://torjo.com/tobias/index.html#boost_utility_singleton._singletons_and_… > appears to be inconsistent: shouldn't mylib_tag and library_tag be the > same, one way or the other? They should. My head must had been on vacation revising the docs. > Also, that example combines three different > mechanisms: BOOST_SINGLETON_PLACEMENT, destroy_singletons() and > SubsystemTag. More explanation of the role of each (why are we using > that mechanism here?), and how they interact -- or remain orthogonal -- > would clarify. Yes. Regards, Tobias

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RFC Generic data structure traversal / manipulation library
by dan marsden 16 Jan '08

16 Jan '08

Hi All I'm posting an early version of a library for manipulating hierarchical data structures, for example the parse trees that are produced by Spirit2. The library enables traversals, and local modifications of complex data structures, without the need to implement large amounts of repetitive traversal code. The library is in a very early state, but has a pretty large introduction and quick start guide, which (hopefully) will help get people started with the library. Formal documentation is unfortunately non-existent at this point. The library is based on techniques from the Haskell community, links to relevant papers are provided in the documentation. The library is intended to play well with the rest of Boost, it already contains support for structures built with Boost.Optional and Boost.Variant, and Boost.Fusion, and will support other Boost libraries in future releases. The library makes heavy use of function objects, and is intended to work with Boost.Lambda, Phoenix, and other function object libraries in Boost. Online documentation can be found at: http://tinyurl.com/2eyjeh A gzip copy of the latest source is available for download at. http://tinyurl.com/2h2tb6 I've also detailed some of the directions that future implementations of the library make take. Any feedback gratefully accepted. Thanks Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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[result_of][borland-5.9.2] BOOST_NO_RESULT_OF
by Jonathan Turkanis 16 Jan '08

16 Jan '08

Hi, I make one fairly modest use of result_of in Boost.Iostreams. My initial implementation included result_of.hpp and guarded the use of result_of with the macro BOOST_NO_RESULT_OF. I then discovered that Borland 5.9.2 and Borland 5.9.3 don't support result_of well enough for my needs, but that result_of.hpp header doesn't set BOOST_NO_RESULT_OF for these toolsets (since they supposedly support SFINAE). So I added checks for Borland version to the guard around result_of. This worked until yesterday. Now it seems that simply including the result_of header fails on Borland (see std_test_result_of_header: http://tinyurl.com/26umcr) I'd like to patch Iostreams as soon as possible, so I'm wondering whether this regression will be resolved by making the header includable by Borland or by marking std_test_result_of_header as an expected failure. It seems to me that result_of.hpp either has to be unconditionally includable, or BOOST_NO_RESULT_OF has to be defined in boost/config.hpp so I can tell whether to include it. If result_of is now really unusable on Borland (and if late model Borland really supports SFINAE), then it's no longer true that BOOST_NO_RESULT_OF is simply the disjunction of two existing config macros, and so it seems natural to define it in config.hpp instead of in result_of.hpp. (It could be defined in config/compiler/borland.hpp and also in config/suffix.hpp if BOOST_NO_SFINAE or BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION is defined.) Thanks, -- Jonathan Turkanis CodeRage http://www.coderage.com

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Re: [boost] [Spirit-devel] RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Eric Niebler wrote: >dan marsden wrote: >> Hartmut Kaiser wrote: >>> Is the used concept extensible in a way allowing for _structural_ >>> changes of the traversed data structure? This would make it usable >>> for tree transformations, which would be especially interesting if >>> used with Spirit.Qi (parsing) and Spirit.Karma (generation). ><snip> >> As for arbitrary transforms from type A to type B, this is probably >> the biggest open question for the library (IMO). > >This is the sort of thing that Proto's tree transformations handle >naturally, but Proto transforms only work when the tree nodes can be >differentiated at compile time. Perhaps there is some synergy between >these two libraries. > >I'm working on the documentation for Proto's new tree transformation >framework right now. Dan, we should talk. Yes, from what I understand of Proto, it is basically providing case analysis on the parse trees for expression template expressions. Its also nicely composable, it's that sort of case analysis type structure that I had in mind. I'd be glad to discuss whether possibly synergies between the 2 approaches. Cheers Dan __________________________________________________________ Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com

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Re: [boost] [Spirit-devel] RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Hartmut Kaiser wrote: >IIUC, the traversal library is designed to help traversing arbitrary data >structures and to apply local _value_ changes. My question is: >Is the used concept extensible in a way allowing for _structural_ changes of >the traversed data structure? This would make it usable for tree >transformations, which would be especially interesting if used with >Spirit.Qi (parsing) and Spirit.Karma (generation). Currently, the most straightforward way to make structural changes to the tree is at nodes where variants are present. Obviously then switching to a subtree of a different type is straightforward. Optional and pointers provide limited scope for eliminating subtrees in a similar way. As for arbitrary transforms from type A to type B, this is probably the biggest open question for the library (IMO). Currently local value changes are pretty well supported within a framework of standard traversals which can be tweaked for certain types. To what extent the library can / should support traversals in which custom behaviour is required at the majority of the nodes is an area I'm currently giving thought to. Ideally I'd like to support at lot more use cases than this first iteration can manage, as things mature, and I incorporate feedback. Cheers Dan __________________________________________________________ Sent from Yahoo! Mail - a smarter inbox http://uk.mail.yahoo.com

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Re: [boost] RFC Generic data structure traversal / manipulation library
by dan marsden 15 Jan '08

15 Jan '08

Larry Evans wrote: >Larry Evans wrote: >> dan marsden wrote: <snip> >> Page: >> >> http://spirit.sourceforge.net/dl_docs/traversal/html/traversal/quick_start_… >> >> contains: >> >> BOOST_FUSION_ADAPT_STRUCT(demo::dept, >> (std::string, name) >> (std::vector<demo::unit>, units)) >> >> I'm assuming demo is a namespace; yet, there's no declaration on that >> page. Also, although I could guess what >> >Sorry, hit wrong button. Continuing: > >Although I could guess what BOOST_FUSION_ADAPT_STRUCT does, it would >help to provide the reference: > >http://spirit.sourceforge.net/dl_more/fusion_v2/libs/fusion/doc/html/fusion… > >I couldn't find any doc on my local copy of fusion, and the boost.org >docs: > >http://www.boost.org/libs/libraries.htm > >had nothing; so, I had to search the mailing list for some location >before I found adapt_struct.html. Thanks for the various bits of feedback, I'm incorporating them into the documentation. If people are interested in the latest stuff, its current hosted in the Spirit Subversion repository at: https://spirit.svn.sourceforge.net/svnroot/spirit/branches/traversal/ I'll also aim to keep the online docs / source reasonably up to date as the library progresses. Cheers Dan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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Re: [boost] [gacap]Is any interesting to "Generating All Combinations and Permutations"？
by hervebronnimann＠mac.com 15 Jan '08

15 Jan '08

Ben, Phil: happy new year. Yes, ben, proposal will only have functions, but boost can (and should) accept more. You can go ahaed and start integrating gacap into proposed boost library. I put it on the prviously mentioned web site, and can do a check into the subversion repo with my version and your changes when all is ready. HB Sent via BlackBerry from T-Mobile

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[Interval] Bug when constructing from an unsigned integer type
by John Maddock 15 Jan '08

15 Jan '08

This compiles: boost::interval<double> in(1u); but creates a nonsense interval. IMO this should work? Likewise the same problem manifests itself when constructing from an unsigned long long (and in this case you really do want a true interval to be created). John.

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Additions to Random/Math
by Andrew Sutton 15 Jan '08

15 Jan '08

I finally got around to committing my additions to the Random and Math libraries this morning. I haven't been able to make much progress since early december due to a) the holidays and b) a burning desire to graduate some time this decade - I've been working on my prospectus. Here's a quick summary of the commit. = Random = - Added 6 or 7 new distributions for random number generation - Added a new gamma distribution that correctly takes 2 parameters - Added a fixed lognormal distribution that correctly allows for a negative mean - Added a new program in libs/generator that will generate random numbers given a distribution and some parameters. Results are printed to cout and comparisons with the statistical distribution (in Boost.Math) are printed to cerr. Works nicely with gnuplot = Math = Added 2 new stubs of distributions (skew normal and geometric). Implemented an alternative version of the extreme_value distribution that supports both min and max variations. This is called extreme_value_i_distribution (i == 1). = What's Missing = Formal testing (outside of the generator tool above). Documentation I'll try to add missing features over the next couple months, but I can't make any guarantees. If authors are worried about "polluting" an existing project, I can easily re-extract them into a new top- level directory in the sandbox since there were no modifications to existing code. Andrew Sutton asutton(a)cs.kent.edu

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[Threads] Dropped support for VC7.0 and earlier?
by John Maddock 15 Jan '08

15 Jan '08

Looks like Boost.Threads no longer compiles with VC7.0 and earlier, is this a deliberate change, or was it unintentional? Just checking, thanks, John.

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