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

[#get_message]
[section get_message]

[h1 Synopsis]

  template <class E>
  struct get_message;

This is a [link lazy_metafunction lazy template metafunction].

[table Arguments
  [[Name] [Type]]
  [[`E`]  [[link reject reject] value]]
]

[h1 Description]

Returns the error message of a parsing failure.

[h1 Header]

  #include <boost/metaparse/get_message.hpp>

[h1 Example]

  #include <boost/metaparse/get_message.hpp>
  #include <boost/metaparse/start.hpp>
  #include <boost/metaparse/reject.hpp>
  #include <boost/metaparse/define_error.hpp>
  
  #include <type_traits>
  
  using namespace boost::metaparse;
  
  BOOST_METAPARSE_DEFINE_ERROR(sample_error, "Sample error message");
  
  struct returns_reject
  {
    using type = reject<sample_error, start>;
  };
  
  static_assert(
    std::is_same<
      sample_error,
      get_message<reject<sample_error, start>>::type
    >::type::value,
    "It should return the message"
  );
  
  static_assert(
    std::is_same<sample_error, get_message<returns_reject>::type>::type::value,
    "It should support lazy evaluation"
  );

[endsect]