Directive for Transduction Parsing (raw[])

Directive for Transduction Parsing (`raw[]`)

Description

The raw[] disregards the attribute of its subject parser, instead exposing the half-open range [first, last) pointing to the matched characters from the input stream. The raw[] directive brings back the classic Spirit transduction (un-attributed) behavior for a subject parser.

Header

// forwards to <boost/spirit/home/qi/directive/raw.hpp>
#include <boost/spirit/include/qi_raw.hpp>

Also, see Include Structure.

Namespace

Name
`boost::spirit::raw // alias: boost::spirit::qi::raw`

Model of

UnaryParser

Notation

a: A Parser.
Iter: A ForwardIterator type.

Expression Semantics

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

Expression	Semantics
`raw[a]`	Disregard the attribute of the subject parser, `a`. Expose instead the half-open range `[first, last)` pointing to the matched characters from the input stream.

Attributes

See Compound Attribute Notation.

Expression	Attribute
`raw[a]`	a: A --> raw[a]: boost::iterator_range<Iter> a: Unused --> raw[a]: Unused

Expression

Attribute

raw[a]

a: A --> raw[a]: boost::iterator_range<Iter>
a: Unused --> raw[a]: Unused

	Note
	See `boost::iterator_range`.

Complexity

The complexity is defined by the complexity of the subject parser, a

Example

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

Some using declarations:

using boost::spirit::qi::raw;
using boost::spirit::ascii::alpha;
using boost::spirit::ascii::alnum;

This parser matches and extracts C++ identifiers:

std::string id;
test_parser_attr("James007", raw[(alpha | '_') >> *(alnum | '_')], id);
std::cout << id << std::endl; // should print James007