Synopsis

template <class P>
struct repeated1;

This is a parser combinator.

Description

It applies P on the input string repeatedly as long as the parser accepts the input. The result of parsing is a sequence of the results of the individual applications of P.

When P rejects the input for the first time, repeated1 rejects it as well. At least one successful application of P is required for repeated1 to accept the input.

Header

#include <boost/metaparse/repeated1.hpp>

Expression semantics

For any p parser the following are equivalent:

repeated1<p>

last_of<look_ahead<p>, repeated<p>>

Example

#include <boost/metaparse/repeated1.hpp>
#include <boost/metaparse/digit_val.hpp>
#include <boost/metaparse/start.hpp>
#include <boost/metaparse/string.hpp>
#include <boost/metaparse/get_result.hpp>
#include <boost/metaparse/is_error.hpp>

#include <boost/mpl/equal.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/int.hpp>

using namespace boost::metaparse;

using digits = repeated1<digit_val>;

static_assert(
  boost::mpl::equal<
    get_result<digits::apply<BOOST_METAPARSE_STRING("1234"), start>>::type,
    boost::mpl::vector<
      boost::mpl::int_<1>,
      boost::mpl::int_<2>,
      boost::mpl::int_<3>,
      boost::mpl::int_<4>
    >
  >::type::value,
  "the result of parsing should be the list of digit values"
);

static_assert(
  is_error<digits::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
  "repeated1 should reject the input when it can't parse anything with digit_val"
);