metaparse/doc/before_5_2_2.qbk

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[#before_5_2_2]
['Definitions before section 5.2.2.]
#include <boost/metaparse/string.hpp>
#include <boost/metaparse/int_.hpp>
#include <boost/metaparse/build_parser.hpp>
using namespace boost::metaparse;
using exp_parser1 = build_parser<int_>;
#include <boost/metaparse/entire_input.hpp>
using exp_parser2 = build_parser<entire_input<int_>>;
#include <boost/metaparse/token.hpp>
using exp_parser3 = build_parser<entire_input<token<int_>>>;
#include <boost/metaparse/lit_c.hpp>
#include <boost/metaparse/sequence.hpp>
using exp_parser4 = build_parser<sequence<token<int_>, token<lit_c<'+'>>, token<int_>>>;
#include <metashell/formatter.hpp>
using int_token = token<int_>;
using plus_token = token<lit_c<'+'>>;
using exp_parser5 = build_parser<sequence<int_token, plus_token, int_token>>;
#include <boost/metaparse/transform.hpp>
#include <boost/mpl/plus.hpp>
#include <boost/mpl/at.hpp>
template <class Vector>
struct eval_plus :
boost::mpl::plus<
typename boost::mpl::at_c<Vector, 0>::type,
typename boost::mpl::at_c<Vector, 2>::type
> {};
#include <boost/mpl/quote.hpp>
using exp_parser6 =
build_parser<
transform<
sequence<int_token, plus_token, int_token>,
boost::mpl::quote1<eval_plus>
>
>;
#include <boost/metaparse/any.hpp>
using exp_parser7 =
build_parser<
sequence<
int_token, /* The first <number> */
repeated<sequence<plus_token, int_token>> /* The "+ <number>" elements */
>
>;
using temp_result = exp_parser7::apply<BOOST_METAPARSE_STRING("1 + 2 + 3 + 4")>::type;
#include <boost/mpl/fold.hpp>
using vector_of_numbers =
boost::mpl::vector<
boost::mpl::int_<2>,
boost::mpl::int_<5>,
boost::mpl::int_<6>
>;
template <class Vector>
struct sum_vector :
boost::mpl::fold<
Vector,
boost::mpl::int_<0>,
boost::mpl::lambda<
boost::mpl::plus<boost::mpl::_1, boost::mpl::_2>
>::type
>
{};
template <class Sum, class Item>
struct sum_items :
boost::mpl::plus<
Sum,
typename boost::mpl::at_c<Item, 1>::type
>
{};