From 5d20c9325ba0e9c732e041ccbab3b0929c30f22a Mon Sep 17 00:00:00 2001
From: Jim Porter <itsjimporter@gmail.com>
Date: Mon, 22 Jul 2024 18:43:21 -0700
Subject: [PATCH] Add support for `char8_t`

---
 CHANGES.md                             |  1 +
 doc/about/changes.md                   |  1 +
 include/mettle/output/string.hpp       |  8 ++++++++
 include/mettle/output/to_printable.hpp |  6 ++++++
 include/mettle/output/traits.hpp       |  3 +++
 test/output/test_string_output.cpp     | 12 ++++++++++--
 test/output/test_to_printable.cpp      | 26 ++++++++++++++++++++++++++
 7 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index a8fe374..48c285b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,6 +9,7 @@
   matchers which need access to non-const objects (e.g. to call a non-const
   member function)
 - New matchers `in_interval` and `exception_what`
+- Add support for `char8_t`
 
 ### Bug fixes
 - Test failures across multiple runs are now correctly grouped in the summary
diff --git a/doc/about/changes.md b/doc/about/changes.md
index cdb3df3..c2f295b 100644
--- a/doc/about/changes.md
+++ b/doc/about/changes.md
@@ -11,6 +11,7 @@ in progress
   matchers which need access to non-const objects (e.g. to call a non-const
   member function)
 - New matchers `in_interval` and `exception_what`
+- Add support for `char8_t`
 
 ### Bug fixes
 - Test failures across multiple runs are now correctly grouped in the summary
diff --git a/include/mettle/output/string.hpp b/include/mettle/output/string.hpp
index 8ce3e73..aedf909 100644
--- a/include/mettle/output/string.hpp
+++ b/include/mettle/output/string.hpp
@@ -50,6 +50,14 @@ namespace mettle {
     return s;
   }
 
+#if __cpp_char8_t
+  inline std::string_view
+  convert_string(const std::u8string_view &s) {
+    return std::string_view(reinterpret_cast<const char *>(s.begin()),
+                            reinterpret_cast<const char *>(s.end()));
+  }
+#endif
+
 // Ignore warnings about deprecated <codecvt>.
 #if defined(_MSC_VER) && !defined(__clang__)
 #  pragma warning(push)
diff --git a/include/mettle/output/to_printable.hpp b/include/mettle/output/to_printable.hpp
index a91cdb1..bdac668 100644
--- a/include/mettle/output/to_printable.hpp
+++ b/include/mettle/output/to_printable.hpp
@@ -49,6 +49,12 @@ namespace mettle {
     return represent_string(std::wstring(1, c), '\'');
   }
 
+#if __cpp_char8_t
+  inline std::string to_printable(char8_t c) {
+    return represent_string(std::u8string(1, c), '\'');
+  }
+#endif
+
   inline std::string to_printable(char16_t c) {
     return represent_string(std::u16string(1, c), '\'');
   }
diff --git a/include/mettle/output/traits.hpp b/include/mettle/output/traits.hpp
index 439e961..dd2f106 100644
--- a/include/mettle/output/traits.hpp
+++ b/include/mettle/output/traits.hpp
@@ -14,6 +14,9 @@ namespace mettle {
 
   template<> struct is_any_char<char> : std::true_type {};
   template<> struct is_any_char<wchar_t> : std::true_type {};
+#if __cpp_char8_t
+  template<> struct is_any_char<char8_t> : std::true_type {};
+#endif
   template<> struct is_any_char<char16_t> : std::true_type {};
   template<> struct is_any_char<char32_t> : std::true_type {};
 
diff --git a/test/output/test_string_output.cpp b/test/output/test_string_output.cpp
index a532897..ac1b59d 100644
--- a/test/output/test_string_output.cpp
+++ b/test/output/test_string_output.cpp
@@ -44,7 +44,11 @@ suite<> test_string_output("string output", [](auto &_) {
   });
 
   subsuite<
-    char, wchar_t, char16_t, char32_t
+    char,
+#if __cpp_char8_t
+    char8_t,
+#endif
+    wchar_t, char16_t, char32_t
   >(_, "convert_string()", type_only, [](auto &_) {
     using C = fixture_type_t<decltype(_)>;
     auto T = &make_string<C>;
@@ -69,7 +73,11 @@ suite<> test_string_output("string output", [](auto &_) {
   });
 
   subsuite<
-    char, wchar_t, char16_t, char32_t
+    char,
+#if __cpp_char8_t
+    char8_t,
+#endif
+    wchar_t, char16_t, char32_t
   >(_, "represent_string()", type_only, [](auto &_) {
     using C = fixture_type_t<decltype(_)>;
     auto T = &make_string<C>;
diff --git a/test/output/test_to_printable.cpp b/test/output/test_to_printable.cpp
index eec57f7..06fe999 100644
--- a/test/output/test_to_printable.cpp
+++ b/test/output/test_to_printable.cpp
@@ -291,6 +291,32 @@ suite<> test_to_printable("to_printable()", [](auto &_) {
       expect(ns, stringified("nullptr"));
     });
 
+#if __cpp_char8_t
+    _.test("char8_t", []() {
+      expect(u8'x', stringified("'x'"));
+      expect(u8'\n', stringified("'\\n'"));
+      expect(u8'\0', stringified("'\\0'"));
+      expect(u8'\x1f', stringified("'\\x1f'"));
+
+      expect(u8"text", stringified("\"text\""));
+      expect(u8"text\nmore", stringified("\"text\\nmore\""));
+      expect(std::u8string(u8"text"), stringified("\"text\""));
+      expect(std::u8string_view(u8"text"), stringified("\"text\""));
+      expect(std::u8string{u8'a', u8'\0', u8'b'}, stringified("\"a\\0b\""));
+
+      char8_t s[] = u8"text";
+      expect(s, stringified("\"text\""));
+      expect(static_cast<char8_t*>(s), stringified("\"text\""));
+
+      const char8_t cs[] = u8"text";
+      expect(cs, stringified("\"text\""));
+      expect(static_cast<const char8_t*>(cs), stringified("\"text\""));
+
+      char8_t *ns = nullptr;
+      expect(ns, stringified("nullptr"));
+    });
+#endif
+
     _.test("char16_t", []() {
       expect(u'x', stringified("'x'"));
       expect(u'\n', stringified("'\\n'"));