...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
The plus operator,
is a unary operator that matches its operand one or more times.
// forwards to <boost/spirit/home/qi/operator/plus.hpp> #include <boost/spirit/include/qi_plus.hpp>
Also, see Include Structure.
Semantics of an expression is defined only where it differs from, or
is not defined in
See Compound Attribute Notation.
a: A --> +a: vector<A> a: Unused --> +a: Unused
The overall complexity of the Plus is defined by the complexity of its subject,
a, multiplied by the number of repetitions. The complexity of the Plus itself is O(N), where N is the number successful repetitions.
The test harness for the example(s) below is presented in the Basics Examples section.
Some using declarations:
using boost::spirit::ascii::alpha; using boost::spirit::qi::lexeme;
Parse one or more strings containing one or more alphabetic characters and put them in a vector:
std::vector<std::string> attr; test_phrase_parser_attr("yaba daba doo", +lexeme[+alpha], attr); std::cout << attr << ',' << attr << ',' << attr << std::endl;