August 2002 - Boost-users - lists.boost.org

boost::any and operator ==
by billrobertson42 27 Aug '02

27 Aug '02

How do I compare two boost::any values for equality? How to I compare two containers of boost::any's for equality? Why doesn't boost::any define this operator? There has to be a reason. Thanks!

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What's your wish list?
by Kevin S. Van Horn 26 Aug '02

26 Aug '02

I'm teaching a graduate class on generic programming this semester, and I'm looking for some solid, meaningful projects for my students. If there are extensions to existing Boost libraries that you would like, or some new C++ library that you would like written, please contact me. -- Kevin S. Van Horn kevin.vanhorn(a)ndsu.nodak.edu

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Using Hash with Graph
by Sandeep Bhutani 26 Aug '02

26 Aug '02

Hi, I am trying to use hash feature with the graph library. Here are the various details: Solaris: SunOS 5.7 Compiler: KAI 4.0 STL: Native Sun Hash: A hacked up version of SGI/STLPort I can get graph to work with vectors/lists. I can't get it to work with the hash_set or hash_map. I get a message from the "concept_checks.h" file in my hash which essentially tells me that the hash function is not defined. I am reproducing the message from the compiler at the bottom. I am trying to make all this work by using the adjacency_list.cpp file in the examples directory. Here is the change I have made to that file: typedef adjacency_list<hash_setS, listS, undirectedS, VertexProperty, EdgeProperty> Graph; // New typedef adjacency_list<vecS, listS, undirectedS, VertexProperty, EdgeProperty> Graph; // Old Can you please help? Has anyone used the has feature in the graph library. I had to edit the line number 166 in adjacency_list.hpp to replace hash_set with hash_map. Thanks -Sandeep The message: "/lsi/home/bhutani/hash/include/concept_checks.h", line 289: error: call of an object of a class type without appropriate operator() or conversion functions to pointer-to-function type return __f(__arg); ^ detected during instantiation of "_Ret _STL_UNARY_FUNCTION_ERROR<_Func, _Ret, _Arg>::__unary_function_requirement_violation(_Func &, const _Arg &) [with _Func=std::hash<boost::detail::adj_list_gen<boost::adjacenc y_list<boost::hash_setS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, size_t, boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>, boost::listS, boost::hash_setS, boost::undirectedS, boost::property<boost::vertex_index_t, size_t, boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>::config::StoredEdge>, _Ret=size_t, _Arg=boost::detail::adj_list_gen<boost::adjacency_list<boos t::hash_setS, boost::listS, boost::undirectedS, boost::property<boost::vertex_index_t, size_t, boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>, boost::listS, boost::hash_setS, boost::undirectedS, boost::property<boost::vertex_index_t, size_t, boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>::config::StoredEdge]" at line 95 of "adjacency_list.cpp" 1 error detected in the compilation of "adjacency_list.cpp". KCC: Compilation failed. boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>, boost::listS, boost::hash_setS, boost::undirectedS, boost::property<boost::vertex_index_t, size_t, boost::property<boost::vertex_color_t, boost::default_color_type, boost::no_property>>, boost::property<boost::edge_name_t, std::string, boost::no_property>, boost::no_property, boost::listS>::config::StoredEdge]" at line 95 of "adjacency_list.cpp" 1 error detected in the compilation of "adjacency_list.cpp". KCC: Compilation failed.

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Had to change typename to class in template declaration of ref.hpp
by Matthias Kronenberger 26 Aug '02

26 Aug '02

Is that a known bug of MSVC? changing all the typename to class removed the error messages.

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Trouble with boost::bind
by stupid_newcomer 26 Aug '02

26 Aug '02

I'm trying to play with boost::bind and boost::mem_fn, however, i have some difficulties with the member function with more than 2 arguments. I have tried a number of time and gone through the documentation , but still can't found an answer. Example: #include <boost/shared_ptr.hpp> #include <boost/mem_fn.hpp> #include <boost/bind.hpp> #include <iostream> #include <vector> #include <algorithm> using namespace std; class B { public: void print0() const { cout << "B::print0 " << endl; } void print1(int i) const { cout << "B::print1 " << i << endl; } void print2(int i, int j) const { // how to call?? cout << "B::print2 " << i << ' '<< j << endl; } }; int main() { typedef boost::shared_ptr<B> Ptr; vector<Ptr> v; for (int i = 0; i < 3; ++i) { v.push_back(boost::shared_ptr<B>(new B())); } // zero argument, OK for_each(v.begin(), v.end(), boost::mem_fn(&B::print0)); // one argument, OK for_each(v.begin(), v.end(), boost::bind(&B::print1, _1, 5)); // two argument, how to call B::print2 ? // for_each(v.begin(), v.end(), /* B::print2 */); return 0; } Thanks for your help!

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regex_match question
by yg-boost-users＠m.gmane.org 25 Aug '02

25 Aug '02

hello everybody i have a trouble with regex_match function. when i try to match a string with a pattern like "(abc)*", and if the string beeng matched contains several subexpressions 'abc', regex_match returns only one match so that i can't iterate through all of them. so, it counts subexp's in the pattern, not in the string. why it happens (i use default flags for regex_match, which must perform what i expect)? and what is the solution to the problem (the one i found so far is to parse in 2 phases - once with regex_match to be sure that the whole string matched, and then to use regex_split. but i'd like to parse the string only once and obtain all the subexp's)? thanks in advance aram

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JAM and boost.pythyon
by sashan 24 Aug '02

24 Aug '02

Hi I've built the Python library and a few of my own test projects. I have problems when trying to link with an external library. Basically I get the 'unresolved external' link error. So I look at the jamfile I'm using and in the dependencies section add the following <dll>E:/code/Library/MyLib Then I run bjam again and the first error I get is E:/Code/Library/Jamfile: No such file or directory So I guess its looking for a Jamfile in that directory. Problem is I don't know what to put inside the Jamfile. Can someone please help? Thank you Sashan

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REGEX - expression doesn't match
by Fr�d�ric Mayot 24 Aug '02

24 Aug '02

Hi, My problem is really simple : I have several regular expressions (like (19[4-9]\d)|(200\d)|( [09]\d ) ) which work when they correspond to the entire string, e.g. : "2002" OK; "something 2002 something" NOT OK. Everythings worked fine with the GRETA library, and now, it doesn't. Does anyone have an idea ? Thanks. Fred

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Re: [Boost-Users] Re: REGEX - expression doesn't match
by dan.ellis＠sophos.com 23 Aug '02

23 Aug '02

> It's simple : I have a string and a regular expression. I only want to > find the FIRST sub-string which matches my regular expression (S), then > to extract the sub-string before S and the sub-string after S. Off the top of my head, it sounds like you want: (.+)(200\d)(.*) -- Dan Ellis, Software Engineer, Sophos Anti-Virus Email: dan.ellis(a)sophos.com, DDI: 01235 540204 Real Business/CBI Growing Business Awards: Company of the Year Tel: 01235 559933, Web: http://www.sophos.com/

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Graph - return edge_descriptor
by Shaw, Richard A 23 Aug '02

23 Aug '02

Can anybody tell my why the find_edge function in the code below fails to get a property if I return the first edge in the list. This is what happens - Find_edge looks for edge A - B It winds it and prints out the edge descriptor, and the weight of the edge It the returns the edge The main code prints out the edge descriptor and the fails when trying to print the weight. BTW - Is there a ready made function to find an edge based on the vertices ? #include <boost/config.hpp> #include <iostream> #include <fstream> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/dijkstra_shortest_paths.hpp> using namespace boost; // Find edge template <class Graph> std::pair<bool, graph_traits<Graph>::edge_descriptor> find_edge(graph_traits<Graph>::vertex_descriptor u, graph_traits<Graph>::vertex_descriptor v, Graph g) { graph_traits<Graph>::out_edge_iterator ei, edge_end; for (boost::tie(ei,edge_end) = out_edges(u, g); ei != edge_end; ++ei) { if (target(*ei, g) == v) { std::cout << "Inside " << *ei << " " << get(edge_weight, g, *ei) << std::endl; return std::make_pair(true, *ei); } } return std::make_pair(false, *ei); // Is there a null edge that I can return ? } int main(int, char *[]) { typedef adjacency_list < listS, vecS, directedS, no_property, property < edge_weight_t, int > > graph_t; typedef graph_traits < graph_t >::vertex_descriptor vertex_descriptor; typedef graph_traits < graph_t >::edge_descriptor edge_descriptor; typedef std::pair<int, int> Edge; const int num_nodes = 5; enum nodes { A, B, C, D, E }; Edge edge_array[] = { Edge(A, C), Edge(B, B), Edge(B, D), Edge(B, E), Edge(C, B), Edge(C, D), Edge(D, E), Edge(E, A), Edge(E, B) }; int weights[] = { 1, 2, 1, 2, 7, 3, 1, 1, 1 }; int num_arcs = sizeof(edge_array) / sizeof(Edge); #ifdef BOOST_MSVC graph_t g(num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get(edge_weight, g); for (std::size_t j = 0; j < num_arcs; ++j) { edge_descriptor e; bool inserted; tie(e, inserted) = add_edge(edge_array[j].first, edge_array[j].second, g); weightmap[e] = weights[j]; } #else graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get(edge_weight, g); #endif graph_traits < graph_t >::edge_descriptor e; bool found; std::cout << "List All" << std::endl; graph_traits < graph_t >::edge_iterator ei, ei_end; for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei) { std::cout << *ei << get(weightmap, *ei) << std::endl; } std::cout << "List Not First" << std::endl; tie(found, e) = find_edge< graph_t >(E, A, g); std::cout << "Outside " << e << get(weightmap, e) << std::endl; // This edge is OK std::cout << "List First" << std::endl; tie(found, e) = find_edge< graph_t >(A, C, g); std::cout << "Outside " << e << get(weightmap, e) << std::endl; // This line fails to get the weight return EXIT_SUCCESS; } Richard Shaw ¤º°`°º¤ø,¸¸,ø¤º°`°º¤ø¤º°`°º¤ø,¸¸,ø¤º°`°º¤ø¤º°`°º¤ø,¸¸,ø¤ Atkins Transport Systems Woodcote Grove Ashley Road Epsom KT18 5BW Direct Dial.: +44 (0) 1372 756407 Switchboard: +44 (0) 1372 726140 Fax: +44 (0) 1372 740055 www.atkinsglobal.com/transportsystems <www.atkinsglobal.com/transportsystems> This email and any attached files are confidential and copyright protected. If you are not the addressee, any dissemination of this communication is strictly prohibited. Unless otherwise expressly agreed in writing, nothing stated in this communication shall be legally binding.

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