List (a % b) - 1.44.0

List (`a % b`)

Description

The list operator, a % b, is a binary operator that matches a list of one or more repetitions of a separated by occurrences of b. This is equivalent to a >> *(b >> a).

Header

// forwards to <boost/spirit/home/qi/operator/list.hpp>
#include <boost/spirit/include/qi_list.hpp>

Also, see Include Structure.

Model of

BinaryParser

Notation

a, b: A Parser

Expression Semantics

Semantics of an expression is defined only where it differs from, or is not defined in BinaryParser.

Expression	Semantics
`a % b`	Match a list of one or more repetitions of `a` separated by occurrences of `b`. This is equivalent to `a >> *(b >> a)`.

Attributes

See Compound Attribute Notation.

Expression	Attribute
`a % b`	a: A, b: B --> (a % b): vector<A> a: Unused, b: B --> (a % b): Unused

Expression

Attribute

a % b

a: A, b: B --> (a % b): vector<A>
a: Unused, b: B --> (a % b): Unused

Complexity

The overall complexity of the List is defined by the complexity of its subject, a, multiplied by the number of repetitions. The complexity of the List itself is O(N), where N is the number successful repetitions.

Example

	Note
	The test harness for the example(s) below is presented in the Basics Examples section.

Some using declarations:

using boost::spirit::qi::int_;

Parse a comma separated list of numbers and put them in a vector:

std::vector<int> attr;
test_phrase_parser_attr(
    "111, 222, 333, 444, 555", int_ % ',', attr);
std::cout 
    << attr[0] << ',' << attr[1] << ',' << attr[2] << ',' 
    << attr[3] << ',' << attr[4] 
    << std::endl;