string.qbk 1.27 KB
[#string]
[section string]

[h1 Synopsis]

  template <char C1, ..., char Cn>
  struct string;

This is a [link metaprogramming_value template metaprogramming value].

[table Arguments
  [[Name]       [Type]]
  [[`C1`..`Cn`] [character values]]
]

[h1 Description]

Compile-time data-structure describing a string object. These string objects are
compatible with `boost::mpl::string`, but they accept only individual characters
as arguments. When `constexpr` is available, they can be constructed using the
[link BOOST_METAPARSE_STRING `BOOST_METAPARSE_STRING`] macro.

The tag of the strings is [link string_tag `string_tag`].

[*C++98]: The maximum length of these strings is controlled by the
`BOOST_METAPARSE_LIMIT_STRING_SIZE` macro.

[*C++11]: The strings use variadic templates.

[h1 Header]

  #include <boost/metaparse/string.hpp>

[h1 Example]

  #include <boost/metaparse/string.hpp>
  
  #include <type_traits>
  
  using namespace boost::metaparse;
  
  using hello1 = string<'H','e','l','l','o'>;
  using hello2 = BOOST_METAPARSE_STRING("Hello");
  
  static_assert(
    std::is_same<
      string<'H', 'e', 'l', 'l', 'o'>,
      BOOST_METAPARSE_STRING("Hello")
    >::type::value,
    "The type generated by the macro should be identical to the hand-crafted one."
  );

[endsect]