EQ2EMu/EQ2/source/depends/boost_1_72_0/libs/metaparse/doc/repeated_reject_incomplete.qbk

[#repeated_reject_incomplete]
[section repeated_reject_incomplete]

[h1 Synopsis]

  template <class P>
  struct repeated_reject_incomplete;

This is a [link parser_combinator parser combinator].

[table Arguments
  [[Name] [Type]]
  [[`P`]  [[link parser parser]]]
]

[h1 Description]

The same as [link repeated `repeated`], but once `P` rejects the input,
`repeated_reject_incomplete` checks if `P` consumes any characters before
rejecting the input. If so, `repeated_reject_incomplete` rejects the input with
the same error message this last application of `P` returned. Otherwise
`repeated_reject_incomplete` accepts the input and gives the same result as
[link repeated `repeated`].

Here is a diagram showing how `repeated_reject_incomplete` works by example:

  using int_token = token<int_>;
  using plus_token = token<lit_c<'+'>>;
  using plus_int = last_of<plus_token, int_token>;
  using sum_op = mpl::lambda<mpl::plus<mpl::_1, mpl::_2>>::type;

[$images/metaparse/repeated_reject_incomplete_diag1.png [width 70%]]

[h1 Header]

  #include <boost/metaparse/repeated_reject_incomplete.hpp>

[h1 Expression semantics]

For any `p` parser, `s` compile-time string and `pos` source position

  repeated_reject_incomplete<p>::apply<s, pos>

is equivalent to

  first_of<repeated<p>, fail_at_first_char_expected<p> >::apply<s, pos>

[h1 Example]

  #include <boost/metaparse/repeated_reject_incomplete.hpp>
  #include <boost/metaparse/lit_c.hpp>
  #include <boost/metaparse/last_of.hpp>
  #include <boost/metaparse/token.hpp>
  #include <boost/metaparse/int_.hpp>
  #include <boost/metaparse/string.hpp>
  #include <boost/metaparse/start.hpp>
  #include <boost/metaparse/get_result.hpp>
  #include <boost/metaparse/is_error.hpp>
  
  #include <boost/mpl/equal.hpp>
  #include <boost/mpl/vector_c.hpp>
  
  using namespace boost::metaparse;
  
  using int_token = token<int_>;
  using plus_token = token<lit_c<'+'>>;
  using plus_int = last_of<plus_token, int_token>;
  
  using ints = repeated_reject_incomplete<plus_int>;
  
  static_assert(
    boost::mpl::equal<
      boost::mpl::vector_c<int, 13, 3, 21>,
      get_result<
        ints::apply<BOOST_METAPARSE_STRING("+ 13 + 3 + 21"), start>
      >::type
    >::type::value,
    "ints should parse the numbers"
  );
  
  static_assert(
    is_error<
      ints::apply<BOOST_METAPARSE_STRING("+ 13 + 3 +"), start>
    >::type::value,
    "when the last number is missing, it should be an error"
  );

[endsect]