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Question on grammar
by Manjunath Kudlur 27 Jan '10

27 Jan '10

I am sure this has been asked before, but I am not able to find an answer to my specific question in the archives. I wanted to create a grammar that can accept statements like if_(expr)[ statement-list ].else_[statement-list]. I created a if_expr type using proto::extends, and added a member called else_ to it, of type proto::function<proto::terminal<if_then_else>, Expr const&>. The code is given below. I am trying to match statements of the above form. Look for if_only_grammar and if_grammar below. The main function has 2 cases, one with just if_ and another with if_ and else_. My grammar matches neither of them. What am I doing wrong? I am quite the newbie to proto, so I am not still able to parse the compiler error message and understand it yet. I will be grateful for any help. Thanks, Manjunath #include <boost/proto/proto.hpp> #include <boost/mpl/bool.hpp> #include <boost/mpl/assert.hpp> #include <iostream> #include <sstream> #include <string> using namespace boost; using namespace std; unsigned int ids; template<typename VT> struct Var { unsigned int id; Var() { id = ++ids; } }; struct if_fun {}; struct program {}; struct if_then_else {}; struct if_domain; template <typename Expr> struct if_expr : proto::extends<Expr, if_expr<Expr>, if_domain> { typedef proto::extends<Expr, if_expr<Expr>, if_domain> base_type; using base_type::operator =; typedef typename proto::result_of::make_expr<proto::tag::function, if_then_else, Expr const &>::type else_type; else_type else_; if_expr(Expr const &e = Expr()) : base_type(e) , else_(proto::make_expr<proto::tag::function>(if_then_else(), boost::ref(e))) {} }; struct if_domain : proto::domain<proto::generator<if_expr> > { }; struct napl_grammar; struct arith_expr_grammar; struct rel_expr_grammar; struct assign_grammar; struct statement_grammar; struct bb_grammar; struct if_only_grammar : proto::or_< proto::subscript<proto::function<if_expr<proto::terminal<if_fun>::type>, rel_expr_grammar >, bb_grammar> > { }; struct if_grammar : proto::or_< if_only_grammar, proto::subscript<proto::function<proto::terminal<if_then_else>, if_only_grammar>, bb_grammar> > { }; struct arith_expr_grammar : proto::or_< proto::plus< arith_expr_grammar, arith_expr_grammar>, proto::minus< arith_expr_grammar, arith_expr_grammar>, proto::multiplies< arith_expr_grammar, arith_expr_grammar>, proto::divides< arith_expr_grammar, arith_expr_grammar>, proto::terminal<Var<int> >, proto::terminal<int>, rel_expr_grammar > { }; struct rel_expr_grammar : proto::or_< proto::less< arith_expr_grammar, arith_expr_grammar>, proto::greater< arith_expr_grammar, arith_expr_grammar>, proto::less_equal< arith_expr_grammar, arith_expr_grammar>, proto::greater_equal< arith_expr_grammar, arith_expr_grammar>, proto::equal_to< arith_expr_grammar, arith_expr_grammar>, proto::not_equal_to< arith_expr_grammar, arith_expr_grammar>, proto::logical_not< rel_expr_grammar> > { }; struct assign_grammar : proto::or_< proto::assign<proto::terminal<Var<int> >, arith_expr_grammar>, proto::assign<proto::terminal<Var<int> >, rel_expr_grammar> > { }; struct statement_grammar : proto::or_< assign_grammar, if_grammar > { }; struct bb_grammar : proto::or_< statement_grammar, proto::comma<bb_grammar, statement_grammar> > { }; struct napl_grammar : proto::or_< proto::terminal<program>, proto::subscript<proto::terminal<program>, bb_grammar> > { }; template<typename Expr> void check_and_execute(const Expr &e, mpl::true_) { cout << "Program printer TBD.\n"; } template<typename Expr> void check_and_execute(const Expr &e, mpl::false_) { cout << "Should not be here\n"; } template<typename Expr> void check_grammar(const Expr &e) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, napl_grammar>::value), SYNTAX_NOT_CORRECT, (void)); check_and_execute(e, proto::matches<Expr, napl_grammar>()); //cout << napl_grammar()(e) << "\n"; } int main() { proto::terminal<Var<int> >::type i1, i2, i3, i4, i5; proto::terminal<program>::type Program; if_expr<proto::terminal<if_fun>::type> if_; int i=4242; check_grammar( Program[ if_(i1 < i2) [ i2 ] ]); /* check_grammar( Program[ if_(i1 < i2) [ i2 ].else_[ i3 ] ]); */ }

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[multi_index] modify_key with an iterator to composite_key
by Christian Holmquist 27 Jan '10

27 Jan '10

Hi, >From what I've found on the net (here: http://groups.google.com/group/boost-list/browse_thread/thread/687ce9662a4c…) about this problem, Joaquin explains that modify_key on a composite_key isn't supported. Relevant part from that thread is: When you use modify_key, you modifier functor is passed > *the key* rather than the whole element as is the case > with modify. In this particular situation, the key is > a composite key; so the key object (defined privately > by composite_key) is some entity that somehow references > entry::m_x and entry::m_y. This object is not exposed > to the public and you're not supposed to try to use > it or modify it, hence the problems you're seeing. > In short, when using composite_key you cannot use > modify_key. The alternative must be to use modify() instead, so I'd like to know how to get the best performance in the following scenario: My index is specified as. namespace bmi = boost::multi_index; struct Index : boost::mpl::vector2 < bmi::hashed_unique<bmi::member<Entry, std::string, &Entry::m_Name> >, bmi::ordered_non_unique < bmi::composite_key < Entry, bmi::member<Entry, int, &Entry::m_State>, bmi::member<Entry, int, &Entry::m_Timestamp> > > > {}; I frequently updated Entry::m_State and Entry::m_Timestamp, but never Entry::m_Name during the lifetime of an entry, thus I expected modify_key to be faster since the expensive hash index don't need to be updated. Since I cannot tell modify() which parts of the Entry I'm about to update, I don't see how I can avoid the rehashing. Maybe there's a better way to configure the index? I'm using Entry::m_State for an equal_range() search, while Entry::m_Timestamp is only for ordering (I bump the timestamp everytime I change m_State). I am using boost.1.35 btw Any response much appreciated, Christian

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Is it possible to sort the vertices in adjacency_list ?
by Konstantin Silav 27 Jan '10

27 Jan '10

Hi, we have a graph with bundled properties for vertices, edges and graph it self. The vertices have X and Y Cartesian coordinates. Now I'd like to SORT them along one of the axis. Is it possible to do it "inside" the graph? Which container should i choose? Custom one? Does this change the edge mapping? Or do I need to copy the vertices in one external container? Thanks in advance!

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Designing a table-like data structure with Fusion
by Matthias Vallentin 27 Jan '10

27 Jan '10

I am in the process of designing a table-like data structure and would like to hear your feedback on the choice of Fusion for this task. In the context of databases, a table contains multiple columns that exhibit different types (short, unsigned int, long long, etc...). Columns must be added at runtime. The table is column-oriented in that it stores each column individually, yet provides a row-oriented interface to add data. The table structure (aka. schema) remains immutable once all columns have been added. To benefit from the heterogeneous nature of Fusion, I would consider a table row a fusion::vector, maybe created using fusion::vector_tie from some arbitrary data. At the very high level, I think of something along the lines of: template <typename T> struct column { void write(const T& x) { // Store x in some fashion (memory or disk). } }; struct table { --> fusion::vector<???> cols; template <typename C> void add_column(C* c) { fusion::push_back(cols, c); } template<typename R> void write(const R& row) { // Writer simply calls c->write(x). fusion::for_each(fusion::zip(row, cols), writer()); } }; int main() { table t; ... auto* ic = new column<int>(); auto* dc = new column<double>(); t.add_column(ic); t.add_column(dc); ... } As you can see (at the mark -->), I need to cross at some point the compile-time/runtime boundary but I am having trouble designing that interface. Perhaps boost::variant might help here to bound the potential number of types? Any kind of thoughts are appreciated. Matthias -- Matthias Vallentin vallentin(a)icsi.berkeley.edu http://www.icir.org/matthias

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BOOST_FUSION_ADAPT_STRUCT: non intrusive macro, get a fusion sequence of struct member types and member names
by Hicham Mouline 27 Jan '10

27 Jan '10

Hello, I am aware that it is planned to implement metafunctions that returned the list of member types of a struct, as well as members names, as fusion/mpl sequences. The macro uses some PP magic. My project has progressed that I think I need this feature to proceed. I may try my hand at implementing these features... Which files in boost/fusion are involved in the implementation of the macro? regards,

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concise error messages
by Manjunath Kudlur 27 Jan '10

27 Jan '10

Hello, I wrote a small DSEL with proto. An example program can be found in the main function below. I use BOOST_MPL_ASSERT_MSG to check an expression against a grammar, and can make the compiler output a small string if the syntax is wrong. But I can do it only for the entire program. Is there a way to do finer grain grammar checking with proto? For example, I haven't defined the "<" operator for expressions, but when I use it in the DSEL code, I get 10 pages of error messages from g++, with the SYNTAX_NOT_CORRECT string somewhere. I would like to get somewhat more accurate than this. Any pointers? Thanks, Manjunath #include <boost/proto/proto.hpp> #include <boost/mpl/assert.hpp> #include <iostream> #include <sstream> #include <string> using namespace boost; using namespace std; unsigned int ids; template<typename VT> struct Var { unsigned int id; Var() { id = ++ids; } }; struct if_fun {}; struct program {}; struct VarName : proto::callable { typedef string result_type; template<typename T> result_type operator()(const Var<T> &v) { stringstream s; s << "V" << v.id; return string(s.str()); } result_type construct(string &l, string op, string &r) { return string(l + op + r); } result_type operator()(proto::tag::plus, string l, string r) { return construct(l, string(" + "), r); } result_type operator()(proto::tag::minus, string l, string r) { return construct(l, string(" - "), r); } result_type operator()(proto::tag::divides, string l, string r) { return construct(l, string(" / "), r); } result_type operator()(proto::tag::multiplies, string l, string r) { return construct(l, string(" * "), r); } result_type operator()(proto::tag::assign, string l, string r) { return string(construct(l, string(" = "), r) + string(";")); } result_type operator()(const int &x) { stringstream s; s << x; return string(s.str()); } result_type operator()(const if_fun&) { return string("if"); } result_type operator()(const program&) { return string("program"); } result_type operator()(proto::tag::function, string l, string r) { stringstream s; s << l << "(" << r << ")"; return string(s.str()); } result_type operator()(proto::tag::subscript, string l, string r) { stringstream s; s << l << " [\n"; s << r; s << "\n]\n"; return string(s.str()); } result_type operator()(proto::tag::comma, string l, string r) { stringstream s; s << l << "\n"; s << r; return string(s.str()); } }; struct napl_grammar; struct expr_grammar; struct bb_grammar; struct if_grammar : proto::or_< proto::when<proto::terminal<if_fun>, VarName(proto::_value)>, proto::when<proto::function<proto::terminal<if_fun>, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), if_grammar(proto::_left), expr_grammar(proto::_right))> > { }; struct expr_grammar : proto::or_< proto::when<proto::plus< expr_grammar, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), expr_grammar(proto::_left), expr_grammar(proto::_right))>, proto::when<proto::minus< expr_grammar, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), expr_grammar(proto::_left), expr_grammar(proto::_right))>, proto::when<proto::multiplies< expr_grammar, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), expr_grammar(proto::_left), expr_grammar(proto::_right))>, proto::when<proto::divides< expr_grammar, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), expr_grammar(proto::_left), expr_grammar(proto::_right))>, proto::when<proto::assign< proto::terminal<Var<int> >, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), expr_grammar(proto::_left), expr_grammar(proto::_right))>, proto::when<proto::terminal<Var<int> >, VarName(proto::_value)>, proto::when<proto::terminal<int>, VarName(proto::_value)>, proto::when<proto::subscript<if_grammar, bb_grammar>, VarName(proto::tag_of<proto::_expr>(), if_grammar(proto::_left), bb_grammar(proto::_right))> > { }; struct bb_grammar : proto::or_< proto::when<expr_grammar, expr_grammar(proto::_expr)>, proto::when<proto::comma<bb_grammar, expr_grammar>, VarName(proto::tag_of<proto::_expr>(), bb_grammar(proto::_left), expr_grammar(proto::_right))> > { }; struct napl_grammar : proto::or_< proto::when<proto::terminal<program>, VarName(proto::_value)>, proto::when<proto::subscript<proto::terminal<program>, bb_grammar>, VarName(proto::tag_of<proto::_expr>(), napl_grammar(proto::_left), bb_grammar(proto::_right))> > { }; template<typename Expr> void check_grammar(const Expr &e) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, napl_grammar>::value), SYNTAX_NOT_CORRECT, (void)); cout << napl_grammar()(e) << "\n"; } template<typename Expr> void check_if_grammar(const Expr&) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, if_grammar>::value), IF_SYNTAX_NOT_CORRECT, (if_grammar)); } template<typename Expr> void check_expr_grammar(const Expr &e) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, expr_grammar>::value), EXPR_SYNTAX_NOT_CORRECT, (expr_grammar)); cout << expr_grammar()(e) << "\n"; } template<typename Expr> void check_bb_grammar(const Expr &e) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, bb_grammar>::value), BB_SYNTAX_NOT_CORRECT, (bb_grammar)); cout << bb_grammar()(e) << "\n"; } int main() { proto::terminal<Var<int> >::type i1, i2, i3, i4, i5; proto::terminal<program>::type Program; proto::terminal<if_fun>::type if_; check_grammar( Program[ i2 = 1 + i2, i3 = i3 * i3, i3=i4/i4, i3=i5-23, if_(i1) [ i2=1, i2, if_(i2) [ i3=1, i3=i5, if_(i3) [ i1=1, i4=42+i4 ] ] ] ] ); /* check_if_grammar( if_(i1)); check_bb_grammar((i4=i1+i2+42, i2=2, i3=i2/42, if_(i1)[i2=3, i3=0])); */ }

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Newbie: Compiling Boost 1.28.0 or later for 64-bit Solaris 10
by Gregory Tyler 27 Jan '10

27 Jan '10

Hi, I'm new to Boost, and I have not used C++ in years. I have been asked to determine whether Boost 1.28.0 (or a later version, if necessary) can be compiled for 64-bit Solaris 10, and if so, then what precautions must be taken. I found this page, which seems to suggest that Boost cannot currently be compiled for Solaris 10: http://groups.google.com/group/boost-list/browse_thread/thread/091716aaf543… On the other hand, this page seem to suggest that it is possible: http://shoaibmir.wordpress.com/2009/08/12/building-boost-under-solaris/ Does anyone have any advice or suggestions? If it matters, I have a Java/JEE background. Thanks in advance, Greg _________________________________________________________________ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/196390706/direct/01/

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[libboost_mpi-vc90-mt-gd-1_40 . lib]Where can I get this library?
by Juliet Villanueva 27 Jan '10

27 Jan '10

Hi: I am trying to configure MPI boost, when you finish all the steps that come within the documentation, and try to compile a simple example, visual compiler tells me that the library lacks libboost_mpi-vc90-mt-gd-1_40 . lib, which is not where you get, I already have installed JAM on my computer, along with the installation of MPI and MPICH2 Boost, recognizes all of MPI include, with out any problem, it only takes me that library, I hope I can help. Tania. Encuentra las mejores recetas en Yahoo! Cocina. http://mx.mujer.yahoo.com/cocina/

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help
by sebastian cheung 27 Jan '10

27 Jan '10

where to begin? I think I have downloaded Boost 1_40 zip, not sure how to start anything with it or do useful appplications? Help

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Re: [Boost-users] C++ and quality of software
by Kenneth Laskoski 26 Jan '10

26 Jan '10

I risk keeping on spamming, but anyway, here are some words from inside Google. Sean Parent once worked at Adobe, where it acted as Adobe Source ibraries developer. ASL is a fine library that I often use as a complement to boost. He recently (Oct 2009) wrote in the asl-devel mailing list: <citation> I'm now at Google working on ChromeOS. The Google style guide (adhered to by most of Google) has made it a bit difficult for me to spend too much time on ASL. [...] Some of the more challenging parts are - limited use of Boost, no exception handling, and discouraged copy and assignment. Right now I feel like I'm coding with one hand behind my back </citation> I think that style guide is pretty phased out by now, almost twelve years after the C++98 Standard. Yours, Kenneth

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