March 2008 - Boost - lists.preview.boost.org

Floating Point Utilities Review Result
by John Maddock 08 Mar '08

08 Mar '08

Floating Point Utilities Review Result. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There were 6 positive reviews and no negative ones, so Johan Rade's Floating Point Utility library has been accepted into Boost. The main issues and topics that came up for discussion were: 1) A couple of minor bugs were uncovered relating to signed NaN testing when using the SSE2 registers, and deserialising NaN's: both were fixed during the review period. 2) We had a discussion about the usefulness or … [View More]

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Which DPI size for equations in HTML docs?
by John Maddock 08 Mar '08

08 Mar '08

By way of experiment I've generated the same equation at various DPI sizes here: http://tinyurl.com/23d74q I'd be interested in feedback on which is the best size to use in HTML docs (PDF's get rather better looking SVG versions rendered). Thanks! John.

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Re: [boost] Eigen vectors?
by Ralf W. Grosse-Kunstleve 08 Mar '08

08 Mar '08

We are using the "Template Numerical Toolkit" (TNT) for Eigensystem calculations (and some other things): http://math.nist.gov/tnt/ ----- Original Message ---- From: David Doria <daviddoria(a)gmail.com> To: boost(a)lists.boost.org Sent: Friday, March 7, 2008 10:31:09 AM Subject: [boost] Eigen vectors? Hi all, I am very new to boost, and I thought I'd do some simple linear algebra examples to get started. I got some simple vector/matrix multiplications going with .../boost/numeric/… [View More]

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Re: [boost] [Boost-testing] [exception] Re: A problem in status/Jamfile.v2 r43539
by Rene Rivera 07 Mar '08

07 Mar '08

David Deakins wrote: > Boris Gubenko wrote: >> The addition of 'build-project ../libs/exception' to status/Jamfile.v2 >> in r43539 causes (full) tests to fail -- see excerpt from bjam.log below. >> This is why HP-UX_ia64_aCC, HP-UX_ia64_gcc and linux_ia64_gcc have >> disappeared from the webpage -- an empty zip archive was uploaded. >> >> I think, it should've been 'build-project ../libs/exception/test' instead. >> > > The jamfile … [View More]

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Trac open bugs - by assignee
by Marshall Clow 07 Mar '08

07 Mar '08

[ 220 open bugs today, 219 yesterday ] If you are maintaining a library, and have not logged into the trac system at <http://svn.boost.org/trac/boost/>, please do so ASAP. Until you do that, no tickets can be assigned to you, and will remain under "None". Instructions on working with tickets can be found at: <http://svn.boost.org/trac/boost/wiki/TicketWorkflow> and a mapping of user names to "real names" can be found at: <http://svn.boost.org/trac/boost/report/16> Bug … [View More]summary 23 djowel 20 az_sw_dude 14 grafik 13 dgregor 12 vladimir_prus 12 doug_gregor 12 dave 11 agurtovoy 10 no-maintainer 9 bemandawes 8 anthonyw 7 turkanis 7 jsiek 6 johnmaddock 5 witt 5 igaztanaga 4 ebf 3 t_schwinger 3 ramey 3 danielw 3 None 2 shammah 2 rogeeff 2 pavol_droba 2 nasonov 2 matias 2 kaalus 2 jmaurer 2 hkaiser 2 danieljames 2 aaron_windsor 1 urzuga 1 speedsnail 1 samuel_krempp 1 pdimov 1 nesotto 1 marshall 1 hljin 1 garcia 1 eric_niebler 1 dlwalker None 1493 SVN files making it through to install None 1644 Boost.Test missing documentation file BOOST_CHECK_CLOSE_FRACTION.html None 1666 Visualizer for boost::optional aaron_windsor 1622 Adjacency list needs to handle self-edges correctly aaron_windsor 778 top-level configure is broken agurtovoy 1001 gcc 4.1.2 segfaults on mpl/test/apply.cpp agurtovoy 1051 MPL header ordering triggers bug agurtovoy 1099 unable to iterate through a "non-explicitly-declared" mpl::set agurtovoy 1215 Boost 1.34.1_ mpl: Wrong workaround detection using MinGW32 (or.hpp_ line #33) agurtovoy 1317 has_xxx randomly broken in msvc agurtovoy 1469 [mpl] nested typedef of set has two different meanings agurtovoy 1476 always<> is not nullary. agurtovoy 1528 g++ 4.3.0 reports error because of redeclaration of next agurtovoy 1549 Boost.MPL: 'index_of' algorithm is not documented agurtovoy 1568 duplicate include guards agurtovoy 588 mpl::remove compile error with gcc 4.1.0 anthonyw 1154 tss destruction segfaults in conjunction with dlopen/dlclose anthonyw 1168 [thread] tss crashes randomly anthonyw 1268 xtime_cmp changes to deal with overflow were reverted anthonyw 1470 Boost.Thread: Compilation errors with non-__cdecl calling convention anthonyw 1640 [Thread] warnings from VC9 + warning level 4 anthonyw 1657 Bug in boost::threads sample anthonyw 876 xtime documentation incomplete anthonyw 881 errors when build with Apache stdcxx az_sw_dude 1028 typo in boost header: date_time/time_defs.hpp az_sw_dude 1078 from_iso_string cannot read the output from to_iso_string az_sw_dude 1098 Urgent libboost-date-time1.33.1 : bugs on ia64 ? az_sw_dude 1147 date_time library contains global #define ERROR az_sw_dude 1160 warning: month_format shadows a member of this az_sw_dude 1162 warning: ticks shadows a member of this az_sw_dude 1289 posix_time::time_facet forgets to pass a_ref argument to base class az_sw_dude 1299 change in typedef stringstream_type in format_date_parser.hpp causing compilation error az_sw_dude 1306 invalid docbook in date_period.xml az_sw_dude 1384 Linking problem with date_time library on Visual C++ 2008 Express az_sw_dude 1386 date_time documentation Jamfile breaks building of boost docs az_sw_dude 1524 format_date_parser.hpp(221) : cannot convert parameter 1 az_sw_dude 1574 operator<< for boost::posix_time::ptime ignores ostream flags az_sw_dude 1674 date_time::date_formatting.hpp: incorrectly formats year using global locale az_sw_dude 287 wrong usage of ios_base::narrow az_sw_dude 316 date_time type conversion warning az_sw_dude 604 from_ftime incorrectly processes FILETIME filled with zeros az_sw_dude 642 operator<< for gregorian::date_duration not found az_sw_dude 889 Insane Dependencies az_sw_dude 890 date_time library supports only the current dst rule bemandawes 1378 filesystem path invalid name for hidden files (LINUX) bemandawes 1389 filesystem::ostream << boost::format generates operator ambigious error (in MSVC++) bemandawes 1458 Darwin Tiger throws std::runtime_error: locale::facet::_S_create_c_locale name not valid bemandawes 1578 bug in readdir_r_simulator() in a multi-threaded environment bemandawes 1583 Serious flaw in boost::filesystem filename handling (opensuse) bemandawes 1589 [filesystem] 'mbstate_t' : is not a member of 'std' bemandawes 1606 filesystem/src/exception.cpp doesn't build with gcc bemandawes 1613 Link Errors against file_system on OS X with Intel Version 10.1 C++ compilers bemandawes 752 directory_iterator doesn't work with catch danieljames 1554 When BOOST_HASH_NO_EXTENSIONS is defined hash doesn't support new string types. danieljames 1555 When BOOST_HASH_NO_EXTENSIONS is defined hash doesn't support boost::system::error_code danielw 1044 Argument pack inaccessable in a functions return type danielw 1054 Parameter takes an "infinite" amount of time to compile with the Intel compiler. danielw 1097 keyword.hpp generates many warnings C4180: qualifier applied to function type has no meaning; ignored dave 1010 linking boost.python on freebsd dave 1019 iterator_facade::pointer should be the return type of operator-> (DR 445) dave 1085 Python rules for compiling in Mac OS X dave 1179 [boost.python] can not export a union in VC2005sp1 dave 1181 [boost.python] can modify enum value dave 1387 Review / update docs to reflect changes dave 1460 Python classes with multiple bases are convertible only to the first class in the lists dave 1482 boost::python::throw_error_already_set should be marked noreturn dave 1516 [python] Failing VC9 regression tests dave 1599 [python] '_set_se_translator': identifier not found dave 865 Use of C++0x keyword as identifier dave 910 gcc strict-aliasing problems with python dgregor 1164 Floyd Warshall broken with unsigned edge weights dgregor 1192 [boostbook] problem when two files have the same name dgregor 1199 configure doesn't work with path containing whitespaces (MacOS X) dgregor 1310 [result_of] const-qualified function pointer doesn't work dgregor 1326 Unable to check graph isomorphism using LEDA adapter dgregor 1391 dominator_tree_test on Borland/CodeGear outputs overly long line dgregor 1394 Translate libs/graph/build/python/Jamfile to BBv2 dgregor 1395 Write Tests for Python Bindings dgregor 1630 gcc-4.3: adjacency_list.hpp includes deprecated header dgregor 1655 Documentation of the depth_first_search() Function dgregor 556 Bundled graph properties dgregor 732 Johnson All-Pairs needs better "no path" information dgregor 736 Const correctness violation djowel 1170 Emit Warnings instead of # symbols in the syntax highlighter djowel 1171 Quickbook title output djowel 1172 non-utf djowel 1176 Space after inline code djowel 1206 Escaping from within code? djowel 1273 CR+LF newlines in position_iterator djowel 1276 spirit problem with _GLIBCXX_DEBUG djowel 1277 Closing section like [pre with } causes Quickbok to crash djowel 1280 sections in imported source files get put inside <para> elements in docbook output djowel 1281 Quickbook produces invalid BoostBook/DocBook XML djowel 1324 tuple should have a swap() that operates element-by-element djowel 1396 wrong result_of invocation around transform_view djowel 1436 [quickbook] inline code inside headings djowel 1484 Quickbook produces illegal docbook for some docinfo fields. djowel 1500 [Spirit/Phoenix] C4512 Compiler warnings from VC8 djowel 1570 Some boost headers aren't ready for gcc 4.3 djowel 1600 duplicate include guard djowel 1601 distane of boost::tuple djowel 1607 Tuple Library Documentation Changes djowel 1610 [MSVC/STLport] [tree/common.hpp] Standard library requirements violation(incomplete type as vector parameter) djowel 1614 vector workaround needed for MSVC9 djowel 1617 spirit gcc-4.3 fix djowel 1619 [Fusion] C4512 warnings from VC9 (Visual Studio 2008) dlwalker 613 boost/crc.hpp uses non-standard conforming syntax doug_gregor 1021 [Graph][reverse_graph] Problem using reverse_graph adapter with an adapted user defined graph doug_gregor 1076 compile error: disconnecting struct with operator()() doesn't work in VS2005 SP1 doug_gregor 375 LEDA graph adaptors do not handle hidden nodes properly doug_gregor 402 random_vertex/random_edge are unnecessarily inefficient doug_gregor 403 Document copy_component doug_gregor 447 reverse_graph and constness of property maps doug_gregor 708 Dijkstra no_init version should not require VertexListGraph doug_gregor 733 Numbered headers don't work with "preferred" syntax doug_gregor 735 Fruchterman-Reingold grid performance can be improved doug_gregor 738 Memory leaks with signal::connect? doug_gregor 829 Implicit graph not implement doug_gregor 852 Problem with Boost and GCC 4.1 ebf 1507 [variant] C4512 warnings from VC8.0 ebf 1548 [variant][docs]typo: formal arg_ operand_ should be v in times_two arglist ebf 1654 recursive variants do not handle nested variants correctly. ebf 993 Variant should use least common multiple of alignments_ rather than maximum eric_niebler 1672 [foreach] compiler warnings from VC8/VC9 garcia 1581 Boost.MultiArray: Resizing bug if the index is not 0-based grafik 1041 Cygwin requires PATH setting. grafik 1322 trac rejects patch attachment as spam grafik 1417 Regresson tests hang in Darwin (Tiger) grafik 1430 Regression fails under Cygwin grafik 1433 Trac's spam detection rejects too many valid messages grafik 1512 Broken link to vacpp in bjam docs. grafik 1513 Broken link to bcpp in bjam docs. grafik 1571 boost bugtracker displays a patch incorrectly grafik 1576 cannot read non-ASCII output messages grafik 1577 Some commands don't work because hStdInput == 0 grafik 1663 build.bat cannot set/reset ERRORLEVEL grafik 616 Boost Jam_ and non english directorys grafik 959 linking fails when Boost is compiled with STLport 5.1.* on Linux (names mismatch) grafik 986 Problem building Python modules on boost 1.34.0 hkaiser 1079 boost-1.34.0 fails to compile. concept checks not satisfied. hkaiser 1670 wave almost unusably slow on real-world input hljin 1522 bit_range friend decl in bit_aligned_pixel_reference.hpp needs to be fully qualified for gcc 4.3 mainline igaztanaga 1080 boost::interprocess win32 global file mapping issue igaztanaga 1210 interprocess::barrier hangs during second use under linux (boost 1.33.1) igaztanaga 1390 Interpocess: managed shared memory failing completely under OS X igaztanaga 1634 boost::interprocess::vector cannot contain volatile int igaztanaga 1635 Incomplete include guard in boost/intrusive jmaurer 351 Diff in state of mersenne_twister gen between GCC3.41 & CW9 jmaurer 599 uniform_01 copies engine instead of using a reference johnmaddock 1081 Empty string rejected as perl-style regex johnmaddock 1314 Using SSE-intrinsics in VC8 causes static assert in type_with_alignment.hpp johnmaddock 1411 Fix BOOST_PARTIAL_SPECIALIZATION_EXPLICT_ARGS johnmaddock 1446 POSIX API doesn't use C locale johnmaddock 1451 error: use of C99 long long integer constant johnmaddock 1626 [type_traits] "bad_alloc is not a member of std" in has_virtual_destructor_test.cpp jsiek 1531 segfault in dynamic_bitset::reference assign operator jsiek 1540 Poisson distribution very slow for large mean (and may also overflow). jsiek 575 Calling subgraph::global_to_local on a root graph jsiek 636 strange compiling problem for transitive_closure jsiek 815 remove_edge core dumps on self-circle jsiek 875 No iterator based constructor for adjacency_matrix jsiek 900 graphml reader namespace handling is broken kaalus 1184 property_tree assignment (operator) bug kaalus 1604 property_tree xml parser doesn't compile with gcc marshall 1252 [pool] severe overhead with unaligned sizes. matias 1406 Understanding the Tables outdated matias 1651 incorrect typedefs in examples nasonov 1220 lexical_cast requires RTTI nasonov 754 boost::any - typeid comparison across shared boundaries nesotto 1629 range/iterator_range.hpp bug no-maintainer 1068 Mersenne twister disables streaming for Visual C++ no-maintainer 1222 lambda::ret<T> should declare result_type. no-maintainer 1270 uniform_smallint doesn't compile with lagged_fibonacci random number generators no-maintainer 1515 [lambda] C4512 warnings from VC8.0 no-maintainer 1544 uniform_01 w/ref template param causes ref to ref error no-maintainer 1546 Method boost::random::uniform_int::operator()(engine_ value) is missing no-maintainer 1572 [lambda] smart pointer const-ness affects its contents no-maintainer 1632 Default Interval rounding policies incomplete no-maintainer 781 Lambda: (_1 + "y")(string("x")) Doesn't Compile no-maintainer 819 uniform_int<> with type's maximum availaible range error pavol_droba 1152 rle_example fails pavol_droba 1385 begin must be boost-qualified pdimov 1106 shared_ptr<T> should not convert to shared_ptr<U> when T* doesn't convert to U* ramey 1285 [serialization] problem when including shared_ptr_132.hpp ramey 1628 Lack of wide character support prevents boost.serialization from linking ramey 1662 boost::serialization for boost::optional - missing include rogeeff 1383 signal.h features not found on Mac OS rogeeff 1542 [test] compiler errors when building with stdcxx library samuel_krempp 859 boost::format ignores a user defined locale shammah 290 perfomance: memory cleanup for pool takes too long shammah 386 boost::pool_allocator breaks with vector of vectors speedsnail 1138 Problems with TSS and static thread library t_schwinger 1100 Building boost.function_types fails cvs rev-1.1_ no chdir command in bash t_schwinger 1602 function_types Jamfile depends on the source tree being in a specific place. t_schwinger 1653 wave executable erroneously required for build of function_types lib turkanis 1523 [iostreams] VC8/VC9 compiler warnings turkanis 1545 [boost/rational.hpp] 'noskipws' is not a member of 'std' turkanis 1579 gzip compressor should model DualUseFilter turkanis 1580 Add static assert to prohibit instantiating a chain with mode dual_use turkanis 1649 Fix definition of JavaScript menu to avoid long chains of functions turkanis 1656 Consider implementing flush() for symmetric filters turkanis 1671 type mismatch of buffer size parameter causes overload resolution to fail urzuga 574 [boost::lambda] Compile error with libstdc++ debug mode vladimir_prus 1165 more quoting problems vladimir_prus 1274 Useless error message vladimir_prus 1321 invalid docbook in tool documentation vladimir_prus 1527 [program_options] Second (and subsequent) lines in tabbed text not aligned correctly vladimir_prus 1530 Program options documentation - Overview - Syntactic Information example typo vladimir_prus 1537 no value given in 'mysql_password =' vladimir_prus 1584 cryptic bbv2 error building quickbook vladimir_prus 1587 [program_options] crashes if value part missing in external configuration file vladimir_prus 1588 [program_options] crashes if value part missing in external configuration file vladimir_prus 1645 Invalid unicode support for default_value vladimir_prus 469 multitoken broken vladimir_prus 689 [program_options] Endless loop with long default arguments witt 1046 Boost.Python quickstart instructions mention nonexistent target witt 583 Fixes for build on IBM pSeries for AIX and Linux witt 834 Homepage regression links witt 957 The "Getting Started" page does not mention the stdlib option witt 973 zip_iterator has value_type == reference -- -- Marshall Marshall Clow Qualcomm, Inc. <mailto:mclow@qualcomm.com> The famous British scientist, Lord Kelvin, said: "When you measure what you are speaking about and express it in numbers, you know something about it, but when you cannot (or do not) measure it, when you cannot (or do not) express it in numbers, then your knowledge is of a meagre and unsatisfactory kind." 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Re: [boost] UTF-8 conversion etc.
by Graham 07 Mar '08

07 Mar '08

>Message: 1 >Date: Thu, 06 Mar 2008 12:22:06 +0000 >From: "Phil Endecott" <spam_from_boost_dev(a)chezphil.org> >Subject: Re: [boost] UTF-8 conversion etc. >To: <boost(a)lists.boost.org> >Message-ID: <1204806126662(a)dmwebmail.dmwebmail.chezphil.org> >Content-Type: text/plain; format="flowed" > >>Graham wrote: >> Phil Endecott wrote: >>> Graham wrote: >>> I have a Unicode character library that I created some time ago with &… [View More]

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Re: [boost] Which DPI size for equations in HTML docs?
by Mathew Robertson 07 Mar '08

07 Mar '08

Hi guys, It is possible to make MSIE work with xhtml, although your sanity may be lost in the process. 1. the file extension itself needs to be ".xml" and the webserver should set the mime-type of "application/xml". 2. the page itself should have the following header: <?xml version="1.0" encoding="utf-8"?> <?xml-stylesheet type="text/xsl" href="copy.xsl"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"&… [View More]

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[proto] Review
by Phil Endecott 07 Mar '08

07 Mar '08

My Proto review follows. I'll say straight away that Proto should certainly be accepted. What it provides is useful, demonstrated by its use in e.g. Spirit; I suspect that even Eric will be surprised by how many and varied the future applications for it will be. The key to that wide usage will be the documentation. That that currently exists is excellent, but more can only help. Eric, why not write a book? This review is the result of about 4 hours playing. I think I've only … [View More]scratched the surface of what's possible. My initial prejudice was that I would find incomprehensible error messages resulting from even the smallest syntax error, making it impossible for me to deviate far from the examples. And very long run-times that make the compiler swap. This was based on my experience with Spirit a few years ago. But I was pleasantly surprised: I'm not sure if that's me getting better at parsing the long error messages that you get from heavily-templated code, or whether the compiler or library had something to do with it. Anyway, I was very pleased with the amount of progress that I made in the time. As an example I decided to try to implement the following. Say I have a multi-threaded application with variables, mutexes and perhaps condition variables bundled like this: template <typename T> struct Locked { T var; Mutex mut; Condition cond; // maybe }; Locked<int> a; Locked<bool> b; I'd like to be able to write something like: b = (a==3 || a>10); and for that to lock the mutexes belonging to a and b, evaluate the expression, and then unlock the mutexes: a.mut.lock(); // Or use a multiple-mutex-locking algorithm with back-off b.mut.lock(); b.var = (a.var==3 || a.var>10); b.mut.unlock(); a.mut.unlock(); Is that possible with Proto? Yes! A variation is to be able to write: wait_until(a==3 || a>10); That would need to lock a's mutex, evaluate the expression, and if it's not true wait on the condition variable and retry. (This gets more complex with more than one variable in the expression as we don't have a way to wait on any one of a set of condition variables.) So the first thing that I need to be able to do is to build a set of all the Locked<> variables in the expression. I need to define an evaluation context in which Locked<> variables return a singleton set of themselves, other terminals return an empty set, and non-terminals return the union of the sets returned by their operands. I'll need to change my Locked<> class slightly so that I can store a set of pointers to them: struct Locked_base { Mutex mut; Condtion cond; // optional }; template <typename T> struct Locked: public Locked_base { T var; }; typedef std::set<Locked_base*> locked_var_set; I'm not very enthusiastic about using a std::set here, since the set will presumably actually be constructed and iterated through at run-time, which has some overhead compared to the code with the explicit mut.lock() and mut.unlock() calls above. Is there some sort of fusion-set or other metaprogramming magic that I could use? Apparently there is and I'll come back to that. Anyway, for now I'll define an evaluation context that builds a std::set: struct get_locked_vars_context: proto::callable_context<get_locked_vars_context const> { typedef locked_var_set result_type; // Return a singleton set for Locked<T>: template <typename T> locked_var_set operator()(proto::tag::terminal, const Locked<T>& l) const { // It took me a while to work out out what the prototype for this should be; // I didn't find anything similar in the examples. locked_var_set s; s.insert(&l); return s; } // Return an empty set for other terminals: template <typename T> locked_var_set operator()(proto::tag::terminal, const T&) const { return locked_var_set(); } // For the operators we need something like this: template <typename Left, typename Right, typename TagT> locked_var_set operator()(TagT, const Left& left, const Right& right) const { locked_var_set s = proto::eval(left,*this); locked_var_set r = proto::eval(right,*this); std::copy(r.begin(),r.end(),std::insert_iterator<locked_var_set>(s,s.end())); return s; } // I'm not sure about the TagT thing up there, but it seems to work. // Presumably something would also be needed for unary expressions. }; So I can now write: get_locked_vars_context ctx; locked_var_set vs = proto::eval( a==proto::as_expr(3) || b, ctx ); // I failed to find as_expr() in the documentation. But while I was writing that I realised that I could just store the locked_var_set in the context and get much simpler code: struct get_locked_vars_context: proto::callable_context<get_locked_vars_context> { locked_var_set var_set; typedef void result_type; template <typename T> void operator()(proto::tag::terminal, Locked<T>& l) { var_set.insert(&l); } template <typename T> void operator()(proto::tag::terminal, const T&) { } template <typename Left, typename Right, typename TagT> void operator()(TagT, Left& left, Right& right) { proto::eval(left,*this); proto::eval(right,*this); } }; and then write: get_locked_vars_context ctx; proto::eval( a==proto::as_expr(3) || b, ctx ); locked_var_set vs = ctx.var_set; Now I need the locking and unlocking, and the actual expression evaluation (which needs a different context): void lock_all(const locked_var_set& vs) { for (locked_var_set::const_iterator i = vs.begin(); i != vs.end(); ++i) { (*i)->mut.lock(); } } void unlock_all(const locked_var_set& vs) { for (locked_var_set::const_reverse_iterator i = vs.rbegin(); i != vs.rend(); ++i) { (*i)->mut.unlock(); } } struct eval_context: proto::callable_context<eval_context const> { typedef int result_type; // ???? The result type for each subexpression will be different, so I don't want // to have to define a result_type here. Presumably this is something that I can // do if I don't use the callable_context convenience, right? How should I do that? // Use the default behaviour for everything, except that for the Locked<> terminals // we read the contained variable. template <typename T> T operator()(proto::tag::terminal, Locked<T>& l) const { return l.var; } }; // Here's a function that does the locking, evaluation and unlocking: template <typename ExprT> int eval_locked_expr(ExprT expr) // same question as above about the result type { get_locked_vars_context glv_ctx; proto::eval(expr, glv_ctx); lock_all(glv_ctx.var_set); eval_context eval_ctx; int r = proto::eval(expr, eval_ctx); unlock_all(glv_ctx.var_set); return r; } // It's used like this: Locked<int> a; Locked<bool> b; eval_locked_expr( a==proto::as_expr(3) || b ); So the only thing that's missing is the actual assignment. Proto doesn't overload operator= because the language only allows it to be overloaded as a member, not as a binary free function. But I can overload operator= inside my Lockable<> class. Would it be possible for me to write: proto::complicated-expr-type MyClass::operator=(proto::other-compilcated-type) { return something...; } ? Or maybe MyClass can inherit from proto::something and get definitions of operator=, operator+= etc. etc. Is that done or do-able? I've no idea how to start coding that, but instead I can do something a bit simpler for this case: template <typename T> struct Locked: public Locked_base { T var; template <typename ExprT> T operator=(ExprT expr) { mut.lock(); T r = var = eval_locked_expr(expr); mut.unlock(); return r; } }; Now that can be used as follows: Locked<int> a; Locked<bool> b; Locked<bool> c; c = ( a==proto::as_expr(3) || b ); (There's a pretty serious flaw with this, which is that if the target of the assignment also appears in the expression then it will attempt to lock it twice.) So the only thing that's needed to "perfect" that is to get rid of the proto::as_expr() noise, which could be done if the 'a' in 'a==3' were a proto expression. Can I do that by adding a conversion to proto::some-complicated-type in Locked<>? Perfect. Except that it will build and iterate through a std::set at run time. So, can I instead build and iterate through a compile-time set? I think that what I need to do is to apply the fold_tree transformation to the expression to get a fusion container of the Locked<> terminals, and then to fusion::for_each to do the locking and the unlocking. Having never used fusion I'm not going to try that now - it's getting late, and it's not going to change my vote! - but if someone would like to work it out for me I'd love to see how to do it. Review questions: - What is your evaluation of the design? Looks good. It would be great if it could all be simpler, but I doubt that's possible. - What is your evaluation of the implementation? I haven't looked inside the source files. I have not encountered any warnings or errors, which is a good sign. - What is your evaluation of the documentation? Good. But the complexity of the subject means that the quality of the documentation will be critical to the widespread uptake of the library. - What is your evaluation of the potential usefulness of the library? Considerable. - Did you try to use the library? With what compiler? Did you have any problems? Yes, with g++ 4.1.3 on Linux. No problems. - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? About 4 hours. - Are you knowledgeable about the problem domain? Not especially. Regards, Phil. [View Less]

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[proto] How to convert a constant into a proto terminal?
by Phil Endecott 06 Mar '08

06 Mar '08

I fear this could be the first of a stream of feeble questions as I try to provoke Proto into life: As the docs say, "Once we have some Proto terminals, expressions involving those terminals build expression trees for us" ... "As long as one operand is a Proto expression, the result of the operation is a tree node representing that operation". In the calculator example, if I write 10 + 20 + _1 then the 10+20 portion is not a proto expression, which happens to be useful behaviour in … [View More]

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[parameter] Does variadic template help to do that?
by vicente.botet 06 Mar '08

06 Mar '08

Hi, I'm interesteed in a non preprocesor solution to the following transformation which bind N args in a mpl sequence (vector) to a boost:parameter:paramers signature. // bind to the signature the Args provided // template <typename Signature, typename... Args> // struct args; template <typename Signature, typename Args> struct args; template <typename Signature, typename Arg0> struct args<Signature, mpl::vector<Arg0> > { typedef typename Signature::template … [View More]

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