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            The plus operator, +a,
            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.
Notation
a
                  A Parser
                
            Semantics of an expression is defined only where it differs from, or
            is not defined in UnaryParser.
          
| Expression | Semantics | 
|---|---|
| 
                       | 
                      Match  | 
See Compound Attribute Notation.
| Expression | Attribute | 
|---|---|
| 
                       | 
 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.
| ![[Note]](../../../../images/note.png) | Note | 
|---|---|
| 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[0] << ',' << attr[1] << ',' << attr[2] << std::endl;