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[GGL] Initial thoughts; how to register point types
by Phil Endecott 15 Nov '09

15 Nov '09

Dear All, Following is some initial feedback on GGL, after spending an hour or so with the docs. I hope to be able to complete a proper review over the next couple of days. The documentation seems very much focused on "how it works", which is of course useful for reviewing the design, but more "what it does" and "how to use it" content would help me to actually try it with some examples. For example, I have a Point<T> class and I would like to "teach" the library about it. From the "Design rationale" page I can see that a number of traits have to be defined, but I don't see a concise reference to what I need to do. Looking at the example "c01_custom_point_example.cpp" I see that there are some macros e.g. GEOMETRY_REGISTER_POINT_2D (not a Boost-style macro name by the way) but I don't see any documentation for what these do. I guess that it defines some traits specialisations, right? Does anyone know how to get Doxygen to create next/prev buttons for navigating between the pages in the e.g. "related pages" section? Is it possible to note which versions of the Boost library dependencies are needed? I'm not convinced that overloading e.g. distance() so that it works with all combinations of geometries is a good idea. If I wanted to know the distance from a point to a polygon I'd be happy to write distance_pt_to_poly(a,b). Having the overload makes it possible for me to accidentally pass the wrong things and get no error. And there is the question of what is meant by distance "to" a polygon - is it to the nearest point, or the centroid, etc? I believe that heterogeneous co-ordinate types (e.g. latitude and longitude of one type and altitude of another) are not supported, right? Regards, Phil.

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 14 Nov '09

14 Nov '09

> Thank you for the snappy reaction. Works lovely. Good news! > I hope you submit it for a formal review soon. Chances are that you > will wait for a review manager for a better part of the decade anyway. I have a review manager (David Abrahams) so we just need to negociate a date with the review wizards. It should definitely last not that long ;-)

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 14 Nov '09

14 Nov '09

> MSM 1.20 allowed writing a state machine with actions/guards which > modify some external state. <snip/> > I no longer instantiate the state machine directly and cannot pass > parameters to constructor and it seems that msm::back::state_machine > will not do this for me (after a quick glance at the definition it > seemed to me that msm::back::state_machine expects its template > parameter to be default constructible). > Is this wrong or am I missing something obvious? Is there some way I > could still achieve the old functionality? No you're not doing anything wrong, it's a use case I simply oversaw, so it's not your fault but mine ;-) So, I corrected the problem and : - added a templated constructor, with up to 5 arguments (can be changed with the BOOST_MSM_CONSTRUCTOR_ARG_SIZE define) - actualized the doc - thanked you for this in the acknowledgments You can download the change (in back/state machine.hpp) from the sandbox (http://svn.boost.org/svn/boost/sandbox/msm/) I tested your case and a few more so it should be ok now. Thanks a lot for the report. I'm happy you like the library. Regards, Christophe

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Re: [boost] [msm] Version 2.0 available
by Christophe Henry 14 Nov '09

14 Nov '09

>No, in this particular scenario I'd leave all the existing transitions in >place and just add the CDLoaded outer state. This is barely more work than >adding the flag, right? Ultimately, what I'm getting at is that your >justifying example in MsmSession_Handout.pdf could be better, because most >Statechart users wouldn't write the code you're implying they would. MSM vs. >Statechart aside, MSM users might be left with the question what flags are >good for when they can achieve the same with an additional outer state. >Again, flags are good, but the justifying example isn't. Ah now I think I now see what you mean. You're using direct entries and need therefore no change to the transitions. Point taken. I can change the example by adding another flag and giving it to one of the CDLoaded-states and one of the non-CDLoaded states, thus preventing the use of an outer state, eventhough it might make the example slightly more difficult than I intended. I really simply wanted to bring this new general concept. Regards, Christophe

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Detached threads and Futures
by ak1mbox-boost＠yahoo.ca 14 Nov '09

14 Nov '09

Hi, I wanted to judge people interest in the following feature and to see [hope :)] that maybe it is already scheduled to appear in the next thread library. I find it often useful to run blocking operations in a fully detached thread. These are often atomic IO operations which receive some input by copy and then if they succeed return some output or error if they fail. The functionality that I need can be described as follow: 1. Encapsulate some code, providing ability to send it any number of parameters 2. Receive notification when this code has finished doing whatever it was supposed to be doing and get the resulting output or error. 3. Be able to terminate all other threads without the fear of the detached thread causing a memory corruption. 4. [Optional] Indicate to the detached thread that it should try to interrupt its operation and exit but not really care if it can't at this point. With Anthony Williams Futures addition to the thread library implementing something like this should not be too difficult. Is this already in the works or would people be interested in someone taking this on as a standalone library and an addition to thread library? Thanks, Alex

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[mirror] C++0x version of the reflection library available
by Matus Chochlik 14 Nov '09

14 Nov '09

Dear list, I would like to announce that a new (alpha) version of the Mirror reflection library, re-written nearly completely from scratch in C++0x, is available at sourceforge.net for those interested, the code can be checked out from the SF repository: https://mirror-lib.svn.sourceforge.net/svnroot/mirror-lib/trunk/impl documentation pre-built with doxygen and DOT is available here: http://kifri.fri.uniza.sk/~chochlik/mirror-lib/html/ Based on a year and a half of user experience with the previous version (the one in Boost sandbox) there have been made several important changes. Just to mention a few: - The meta-objects should be more consistent with the base-level language - There is a run-time layer with an run-time interface very similar to the compile-time interface - Meta-object categories for tag dispatching have been added - "Local" names having parts of the nested name specifier stripped away if the Mirror's "using namespace" directive is used on the current (or parent) scope - C++0x features are extensively used to make things more straightforward - etc. This version does not yet implement all features from the previous version, like inherited class members, visitor-based traversals, meta-constructors and factory generators. These will be added in the near future. The library has been tested only with gcc (version 4.5.0 20091010) so I would be glad to hear about experiences with other compilers supporting C++0x. I would also appreciate any feedback, suggestions or other contributions. best regards, Matus

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[iostreams] 64bit compile issue
by Christoph 14 Nov '09

14 Nov '09

in boost/iostreams/detail/streambuf/indirect_streambuf.hpp:171: error: no matching function for call to 'max(int, std::streamsize&)' suggest fix: cast 2 to std::streamsize Best regards Christoph

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Halycon Days?
by Paul A. Bristow 14 Nov '09

14 Nov '09

http://tinyurl.com/yau3k57 see also youtube.com As Nom says - it is dead easy now there is a cable ;-) Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

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[Serialization] warnings and maybe a 'bug'
by Christoph Duelli 14 Nov '09

14 Nov '09

(I tried to file a ticket, but got cookie trouble. Therefore I post here. Sorry for the inconvenience.) i) warnings (unused parameter) (These warnings are with gcc, 4.2.1) boost/serialization/shared_ptr.hpp:116: warning: unused parameter 'file_version' boost/archive/shared_ptr_helper.hpp:110: warning: unused parameter 't' /boost/archive/detail/iserializer.hpp:474: warning: unused parameter 'ar' (and 't', same line) I also get lots of boost::archive::detail::<unnamed>::init_guid<XXXX>::g' defined but not used where XXXX is some class name of mine ii) maybe a 'bug' (code does no longer compile) Code that used to compile with Boost 1.40 does no longer compile with the 1.41 beta: (I had no time to investigate yet; in case it is obvious for you once you see the code I have decided to include this point in this posting): boost/archive/shared_ptr_helper.hpp:114: error: cannot convert 'const boost::serialization::extended_type_info_typeid<MEPfad>' to 'const boost::serialization::extended_type_info*' in return (where MEPfad is a class of mine) Best regards Christoph

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Beta build of PDF docs available for 1.41
by John Maddock 14 Nov '09

14 Nov '09

A beta build of the PDF documentation build for Boost-1.41 is available from the usual sourceforge page: https://sourceforge.net/project/admin/explorer.php?group_id=7586 in the Boost-docs/1.41.0 directory. Or directly from https://sourceforge.net/projects/boost/files/boost-docs/1.41.0/boost_pdf_1_…. If Boost authors would like to skim these for the usual SNAFU's that would be great. Otherwise I intend to release the final PDF build at the same time as Boost-1.41.0. Enjoy, John.

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