libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   3 // See https://llvm.org/LICENSE.txt for license information.
   4 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   5 //
   6 //===----------------------------------------------------------------------===//
   7
   8 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
   9
  10 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
  11
  12 // [container.adaptors.format]
  13 // For each of queue, priority_queue, and stack, the library provides the
  14 // following formatter specialization where adaptor-type is the name of the
  15 // template:
  16 //
  17 // template<class charT, class T, formattable<charT> Container, class... U>
  18 //   struct formatter<adaptor-type<T, Container, U...>, charT>
  19
  20 // template<class ParseContext>
  21 //   constexpr typename ParseContext::iterator
  22 //     parse(ParseContext& ctx);
  23
  24 // Note this tests the basics of this function. It's tested in more detail in
  25 // the format functions test.
  26
  27 #include <cassert>
  28 #include <concepts>
  29 #include <format>
  30 #include <queue>
  31 #include <stack>
  32
  33 #include "test_format_context.h"
  34 #include "test_macros.h"
  35 #include "make_string.h"
  36
  37 #define SV(S) MAKE_STRING_VIEW(CharT, S)
  38
  39 template <class Arg, class StringViewT>
  40 constexpr void test_parse(StringViewT fmt, std::size_t offset) {
  41   using CharT    = typename StringViewT::value_type;
  42   auto parse_ctx = std::basic_format_parse_context<CharT>(fmt);
  43   std::formatter<Arg, CharT> formatter;
  44   static_assert(std::semiregular<decltype(formatter)>);
  45
  46   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
  47   assert(it == fmt.end() - offset);
  48 }
  49
  50 template <class StringViewT>
  51 constexpr void test_parse(StringViewT fmt, std::size_t offset) {
  52   test_parse<std::queue<int>>(fmt, offset);
  53   test_parse<std::priority_queue<int>>(fmt, offset);
  54   test_parse<std::stack<int>>(fmt, offset);
  55 }
  56
  57 template <class CharT>
  58 constexpr void test_fmt() {
  59   test_parse(SV(""), 0);
  60   test_parse(SV(":d"), 0);
  61
  62   test_parse(SV("}"), 1);
  63   test_parse(SV(":d}"), 1);
  64 }
  65
  66 constexpr bool test() {
  67   test_fmt<char>();
  68 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  69   test_fmt<wchar_t>();
  70 #endif
  71
  72   return true;
  73 }
  74
  75 int main(int, char**) {
  76   test();
  77   static_assert(test());
  78
  79   return 0;
  80 }