Using Boost.Spirit, when I group nodes with a leaf_node_d directive and call parse_ast, it looks like I get a node whose value includes some characters that are supposed to be skipped.

My questions: am I missing anything? Is this intended? If yes, what am I missing (again)? Is there a way to work around this?

Here is a simple example program (it should compile and demonstrate what I mean, with boost 1.39 and 1.40)

The implementation of AST's in Spirit.Classic is known to be slow and buggy at times. That's one of the reasons why we developed Spirit 2 (now released with Boost 1.41, but usable with any Boost >= V1.37). You should consider switching to the new version! Regards Hartmut ------------------- Meet me at BoostCon http://boostcon.com

// BEGIN OF THE PROGRAM #include <iostream>

#include <boost/spirit/include/classic_core.hpp> #include <boost/spirit/include/classic_lists.hpp> #include <boost/spirit/include/classic_ast.hpp> #include <boost/spirit/include/classic_tree_to_xml.hpp>

namespace bs = boost::spirit::classic;

template< typename IteratorT > class OkGrammar : public bs::grammar< OkGrammar< IteratorT > > { public:     template< typename ScannerT >     struct definition {         bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 1 > >         start() { return startRule; }

        definition( const OkGrammar& ) {             startRule = bs::list_p( identifier, bs::ch_p( ',' ) );

            identifier = +bs::alpha_p;         }

        bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 1 > > startRule;         bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 2 > > identifier;     }; };

...

{

template< typename IteratorT > class StrangeGrammar : public bs::grammar< StrangeGrammar< IteratorT > public:     template< typename ScannerT >     struct definition {         bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 1 > >         start() { return startRule; }

        definition( const StrangeGrammar& ) {             startRule = bs::list_p( identifier, bs::ch_p( ',' ) );

            identifier = bs::leaf_node_d[ +bs::alpha_p ];         }

        bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 1 > > startRule;         bs::rule< ScannerT, bs::parser_context<>, bs::parser_tag< 2 > > identifier;     }; };

int main( int argc, char *argv[] ) {     std::string input = "     Hello    ,    wor  ,  ld    ";

    std::map< bs::parser_id, std::string > ruleNames;     ruleNames[ 1 ] = "startRule";     ruleNames[ 2 ] = "identifier";

    typedef std::string::const_iterator iterator;     iterator first = input.begin();     iterator last = input.end();

    bs::tree_parse_info< iterator > info = bs::ast_parse(         first,         last,         OkGrammar< iterator >(),         +bs::space_p );     bs::tree_to_xml( std::cout, info.trees, input, ruleNames );

    std::cout << std::endl;

    info = bs::ast_parse(         first,         last,         StrangeGrammar< iterator >(),         +bs::space_p );     bs::tree_to_xml( std::cout, info.trees, input, ruleNames ); } // END OF THE PROGRAM

Here is the output: <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE parsetree SYSTEM "parsetree.dtd"> <!--      Hello    ,    wor  ,  ld     --> <parsetree version="1.0">     <parsenode rule="startRule">         <parsenode rule="identifier">             <parsenode>                 <value>H</value>             </parsenode>             <parsenode>                 <value>e</value>             </parsenode>             <parsenode>                 <value>l</value>             </parsenode>             <parsenode>                 <value>l</value>             </parsenode>             <parsenode>                 <value>o</value>             </parsenode>         </parsenode>         <parsenode>             <value>,</value>         </parsenode>         <parsenode rule="identifier">             <parsenode>                 <value>w</value>             </parsenode>             <parsenode>                 <value>o</value>             </parsenode>             <parsenode>                 <value>r</value>             </parsenode>         </parsenode>         <parsenode>             <value>,</value>         </parsenode>         <parsenode rule="identifier">             <parsenode>                 <value>l</value>             </parsenode>             <parsenode>                 <value>d</value>             </parsenode>         </parsenode>     </parsenode> </parsetree>

<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE parsetree SYSTEM "parsetree.dtd"> <!--      Hello    ,    wor  ,  ld     --> <parsetree version="1.0">     <parsenode rule="startRule">         <parsenode rule="identifier">             <value>Hello</value>         </parsenode>         <parsenode>             <value>,</value>         </parsenode>         <parsenode rule="identifier">             <value>    wor</value>         </parsenode>         <parsenode>             <value>,</value>         </parsenode>         <parsenode rule="identifier">             <value>  ld</value>         </parsenode>     </parsenode> </parsetree>

In the first xml tree, there are no node with spaces, while in the second, the identifiers do have spaces.

Thank you for your help, -- Vincent Jacques

"S'il n'y a pas de solution, c'est qu'il n'y a pas de problème"            Devise Shadock