Run Code
|
API
|
Code Wall
|
Misc
|
Feedback
|
Login
|
Theme
|
Privacy
|
Patreon
Spirit Lex combining token_id's with semantic actions
#include <iostream> #include <string> #include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/lex_lexertl.hpp> #include <boost/spirit/include/phoenix.hpp> using namespace boost::spirit; namespace phx = boost::phoenix; enum token_id //ADDED { ID_ELLIPSES = lex::min_token_id + 1, ID_NUMBER }; /////////////////////////////////////////////////////////////////////////////// // Token definition /////////////////////////////////////////////////////////////////////////////// template <typename Lexer> struct example3_tokens : lex::lexer<Lexer> { example3_tokens() { // define the tokens to match ellipses = "\\.\\.\\."; number = lex::token_def<>("[0-9]+", ID_NUMBER); //CHANGED ellipses.id(ID_ELLIPSES); //CHANGED // associate the tokens and the token set with the lexer this->self = ellipses[phx::ref(std::cout) << "Found ellipses.\n"] | '(' | ')' | number[phx::ref(std::cout) << "Found: " << phx::construct<std::string>(lex::_start, lex::_end) << '\n']; //CHANGED // define the whitespace to ignore (spaces, tabs, newlines and C-style // comments) this->self("WS") = lex::token_def<>("[ \\t\\n]+") // whitespace | "\\/\\*[^*]*\\*+([^/*][^*]*\\*+)*\\/" // C style comments ; } // these tokens expose the iterator_range of the matched input sequence lex::token_def<> ellipses, identifier, number; }; /////////////////////////////////////////////////////////////////////////////// // Grammar definition /////////////////////////////////////////////////////////////////////////////// template <typename Iterator, typename Lexer> struct example3_grammar : qi::grammar<Iterator, qi::in_state_skipper<Lexer> > { template <typename TokenDef> example3_grammar(TokenDef const& tok) : example3_grammar::base_type(start) { start = +(couplet | qi::token(ID_ELLIPSES)) //CHANGED ; // A couplet matches nested left and right parenthesis. // For example: // (1) (1 2) (1 2 3) ... // ((1)) ((1 2)(3 4)) (((1) (2 3) (1 2 (3) 4))) ... // (((1))) ... couplet = qi::token(ID_NUMBER) //CHANGED | '(' >> +couplet >> ')' ; BOOST_SPIRIT_DEBUG_NODE(start); BOOST_SPIRIT_DEBUG_NODE(couplet); } qi::rule<Iterator, qi::in_state_skipper<Lexer> > start, couplet; }; /////////////////////////////////////////////////////////////////////////////// int main() { // iterator type used to expose the underlying input stream typedef std::string::iterator base_iterator_type; // This is the token type to return from the lexer iterator typedef lex::lexertl::token<base_iterator_type> token_type; // This is the lexer type to use to tokenize the input. // Here we use the lexertl based lexer engine. typedef lex::lexertl::actor_lexer<token_type> lexer_type; //CHANGED // This is the token definition type (derived from the given lexer type). typedef example3_tokens<lexer_type> example3_tokens; // this is the iterator type exposed by the lexer typedef example3_tokens::iterator_type iterator_type; // this is the type of the grammar to parse typedef example3_grammar<iterator_type, example3_tokens::lexer_def> example3_grammar; // now we use the types defined above to create the lexer and grammar // object instances needed to invoke the parsing process example3_tokens tokens; // Our lexer example3_grammar calc(tokens); // Our parser std::string str ="(1) (1 2) (1 2 3) ... ((1)) ((1 2)(3 4)) (((1) (2 3) (1 2 (3) 4))) ... (((1))) ..."; //CHANGED // At this point we generate the iterator pair used to expose the // tokenized input stream. std::string::iterator it = str.begin(); iterator_type iter = tokens.begin(it, str.end()); iterator_type end = tokens.end(); // Parsing is done based on the token stream, not the character // stream read from the input. // Note how we use the lexer defined above as the skip parser. bool r = qi::phrase_parse(iter, end, calc, qi::in_state("WS")[tokens.self]); if (r && iter == end) { std::cout << "-------------------------\n"; std::cout << "Parsing succeeded\n"; std::cout << "-------------------------\n"; } else { std::cout << "-------------------------\n"; std::cout << "Parsing failed\n"; std::cout << "-------------------------\n"; } std::cout << "Bye... :-) \n\n"; return 0; }
run
|
edit
|
history
|
help
0
solution_problem4
Waiting for Multiple Objects
ntohl
WinAPI not accessible
no-thread
hex manip
typeid VC++
hyy
Default constructor - none defined
DCapSurfaceDesc