Synopsis

struct int_;

This is a parser.

Description

It accepts a non-empty sequence of characters in the range 0-9. The result of the parser is the decimal value represented by the accepted character sequence.

Header

#include <boost/metaparse/int_.hpp>

Expression semantics

The following are equivalent:

int_

foldl1<
  digit_val,
  boost::mpl::int_<0>,
  boost::mpl::lambda<
    boost::mpl::plus<
      boost::mpl::times<boost::mpl::_2, boost::mpl::int_<10>>,
      boost::mpl::_1
    >
  >::type
>

Example

#include <boost/metaparse/int_.hpp>
#include <boost/metaparse/string.hpp>
#include <boost/metaparse/start.hpp>
#include <boost/metaparse/is_error.hpp>
#include <boost/metaparse/get_result.hpp>

using namespace boost::metaparse;

static_assert(
  get_result<
    int_::apply<BOOST_METAPARSE_STRING("13"), start>
  >::type::value == 13,
  "It should parse an integer value"
);

static_assert(
  is_error<int_::apply<BOOST_METAPARSE_STRING("six"), start>>::type::value,
  "It should reject the input if it is not a number"
);