April 2007 - Boost-users - lists.boost.org

Boost graph point of contact
by Stephen Torri 16 Apr '07

16 Apr '07

What group of people or person is a good contact for assistance with the boost graph library? I have not heard back anyone since Friday about a error I am receiving from a test program that I posted. I was wondering if I was going about finding help the wrong way. Stephen

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Regex, no output of greed example.
by Graham Reitz 16 Apr '07

16 Apr '07

There is no output with the following example, when "Note that I'm 21 years old, not" for m[1], and "35" for m[2], is expected. (according to the example): boost::regex reg("(.*)(\\d{2})"); boost::cmatch cm; const char* text = "Note that I'm 21 years old, not 35."; if (boost::regex_search(text, cm, reg)) { if (cm[1].matched) { std::cout << "(.*) matched: " << m[1].str() << std::endl; } if (cm[2].matched) { std::cout << "Found the age: " << m[2].str() << std::endl; } } Output: (.*) matched: Found the age: Expecting: (.*) matched: Note that I'm 21 years old, not Found the age: 35 Any help would be much appreciated. I am new to regular expression and boost::regex. Thanks, Graham

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Boost.Regex with QChar?
by Sebastian Pipping 15 Apr '07

15 Apr '07

It seems to me like Boost.Regex is much more powerful than QRegExp of QT. Can Boost.Regex work with QChar [1] as charT? The text "i.e. either char or wchar_t" on [2] made me unsure of this. Any limitations I should know about? Thanks for your help! Sebastian [1] http://doc.trolltech.com/4.3/qchar.html [2] http://www.boost.org/libs/regex/doc/basic_regex.html

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[dynamic_bitset] beginner question - concatenation/slicing
by Kurt Schwehr 15 Apr '07

15 Apr '07

Hi All, I am new to boost and haven't done much c++ programming in the last couple years, so apologies if this question is obvious. I'm looking at dynamic_bitset to build a translator between the bits and NMEA string packaging for Maritime AIS. Basically this is each character in a string represents 6 bits of data. I'd like to make two lookup tables that let me go back and forth quickly between bitsets and the NMEA ASCII. My dynamic_bitset questions are: * how can I best concatenate multiple dynamic_bitsets? For example: lookupbits['a']+lookupbits['1']+lookupbits['g'] would return a dynamic_bitset of 18 bits. I'm looking for some sort of join operation and append does not seem to do what I want. * How can I best slice the results? If I know that, for example, and unsigned integer is at bits 11-14, is there way to do quickly get a dynamic_bitset of those bits? I've got all this working in pure python, but it is way to slow ( http://vislab-ccom.unh.edu/~schwehr/software/noaadata/ in the ais package). Any suggestions would be greatly appreciated. Thanks! -kurt http://schwehr.org

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BGL: need help with connected_components and boost::setS
by Maarten Nieber 15 Apr '07

15 Apr '07

Hi all, can anyone help me with the compile error I get when compiling the following code? I'm using the MSVC 7.1 compiler (but it is not an internal compiler error). The error occurs in the last line. Your help is appreciated! With kind regards Maarten #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/connected_components.hpp> // Identifies the "component number" property struct component_t { enum { num = 4564 }; typedef boost::vertex_property_tag kind; }; void Test() { using namespace boost; // The "component number" property is an integer for each vertex typedef boost::property<component_t, int> VertexComponentProperty; // A graph with list storage and the "component number" property. typedef boost::adjacency_list < boost::setS, boost::setS, boost::undirectedS, VertexComponentProperty > Graph; // The property map typedef boost::property_map<Graph, component_t>::type ComponentPropertyMap; Graph g; ComponentPropertyMap vertexToComponent = boost::get(component_t(), g); // THIS LINE DOES NOT COMPILE. No problem if boost::vecS is used instead of boost::setS in the Graph typedef! connected_components(g, vertexToComponent); } __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Boost Regex in a DLL
by Metasebia Moges 15 Apr '07

15 Apr '07

Hi All, I wanted to use boost::regex in a DLL whose methods are called a number of times by the main program. The code I wrote in the DLL compiles and builds without any problem. The code in the DLL seems to do the job the first time the DLL is called by the main program but the next time the DLL is called to do the same job again in the same run of the program, it halts. When I do the same piece of job using the standard C++ libraries somehow, everything works fine but not with boost regex. Why? I am not sure if there is any #define or something I missed when boost regex is used in a DLL. Just confused .... FYI: I use Visual C++ 2003. I appreciate any help. mmoges __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Regex: awk
by Metasebia Moges 15 Apr '07

15 Apr '07

Hi All, I am introduced to Boost Regex recently and I have tried a few examples and it seems quite powerful. My question: I would like to do what I could with "awk" using regex in Visual C++. For instance, to parse a line containing space as a separator. I think it is designed for adding such capabilities to C++ and I hope there exists an easy way to do so. I appreciate any useful information. Best regards, mmoges. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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[gil] new io for bmp and pnm files for gil 2.0
by Christian Henning 15 Apr '07

15 Apr '07

Hi there, the io for bmp and pnm files have been updated to compile with gil 2.0. For some reasons I was treading the whole process of updating. But I can happily report that migration was easier than I thought. Files are available at: https://gil-contributions.googlecode.com/svn/trunk/gil_2 Any comments are welcome. Christian

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Re: [Boost-users] Spirit2 cookbook example suggestions welcome
by Joel de Guzman 14 Apr '07

14 Apr '07

ebo(a)sandien.com wrote: > Joel de Guzman <joel(a)boost-consulting.com> said: > >> ebo(a)sandien.com wrote: >> >> EBo! So nice to see you every now and then. > > Joel! You always make me feel so welcome ;-) > >>> Something I was playing around with a couple of years ago and never took the >>> project to full production was a user extensible machine-tool parser which >>> kept the rules and the grammar in persistent dynamically loadable objects. I >>> was able to load new commands on the fly, or actually change the grammar rules >>> themselves... >>> ... >>> Would something like that be interesting? >> Yeah, that's cool! I'm not sure it fits the criteria I outlined though. > > I'll review the criteria tomorrow... > >> Seems to be too complex for the cookbook? > > How many lines/pages of code and description is reasonable? The entire > framework for the above is something like 1,750 lines of code, but that > includes the dynamic parser and 28 RS-274 M and G codes. Stripped down for a > minimal example could be a fraction of that. Anyway, maybe we can come up > with something appropriate. I'm thinking more in the tune of a few lines of grammar here and there -- small enough to digest in a few minutes. Something like... if you want to do something like this, you write something like this. Example: "I want to parse pascal style strings where the first byte is the length (N) of the string, followed by N characters. How do you do it?" Of course that's a very simple example. We have more elaborate examples like "How do you write a C-like language and a virtual machine?". We have that. Now, I want some more in-betweens. Regards, -- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net

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[boost::statechart] some questions
by Jeffrey Holle 14 Apr '07

14 Apr '07

I'm using boost CVS version gotten on Fri Apr 6 11:48:58 EDT 2007. I'm starting to use boost::statechart for the first time. Scanning the available documentation has produced some questions. I found the following text in a C++ comment within the tutorial: context<>() is used to gain access to the direct or indirect context of a state. This can either be a direct or indirect outer state or the state machine itself. 1, What does "direct" "indirect" context mean? It is documented a number of places that the possible types of reactions are: 1. custom-reaction 2. in-state-reaction 3. deferral 4. transition 2. What is the syntax for using an "in-state-reaction", which I assume is a self transition? 3. What is a custom-reaction? 4. What is a deferral?

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