From a32cd6cb61a62fe8f9c4059ca2c428e945d17adc Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Wed, 16 Sep 2020 21:24:03 +0900
Subject: [PATCH] feat: enable to use u8""_toml literal in C++20

---
 toml/literal.hpp | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/toml/literal.hpp b/toml/literal.hpp
index 5292b3d..2c3d18c 100644
--- a/toml/literal.hpp
+++ b/toml/literal.hpp
@@ -11,12 +11,9 @@ inline namespace literals
 inline namespace toml_literals
 {
 
-inline ::toml::value operator"" _toml(const char* str, std::size_t len)
+// implementation
+inline ::toml::value literal_internal_impl(::toml::detail::location loc)
 {
-    ::toml::detail::location
-        loc(/* filename = */ std::string("TOML literal encoded in a C++ code"),
-            /* contents = */ std::vector<char>(str, str + len));
-
     // if there are some comments or empty lines, skip them.
     using skip_line = ::toml::detail::repeat<toml::detail::sequence<
             ::toml::detail::maybe<::toml::detail::lex_ws>,
@@ -78,8 +75,32 @@ inline ::toml::value operator"" _toml(const char* str, std::size_t len)
     {
         throw ::toml::syntax_error(data.unwrap_err(), source_location(loc));
     }
+
 }
 
+inline ::toml::value operator"" _toml(const char* str, std::size_t len)
+{
+    ::toml::detail::location loc(
+            std::string("TOML literal encoded in a C++ code"),
+            std::vector<char>(str, str + len));
+    return literal_internal_impl(std::move(loc));
+}
+
+// value of __cplusplus in C++2a/20 mode is not fixed yet along compilers.
+// So here we use the feature test macro for `char8_t` itself.
+#if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
+// value of u8"" literal has been changed from char to char8_t and char8_t is
+// NOT compatible to char
+inline ::toml::value operator"" _toml(const char8_t* str, std::size_t len)
+{
+    ::toml::detail::location loc(
+            std::string("TOML literal encoded in a C++ code"),
+            std::vector<char>(reinterpret_cast<const char*>(str),
+                              reinterpret_cast<const char*>(str) + len));
+    return literal_internal_impl(std::move(loc));
+}
+#endif
+
 } // toml_literals
 } // literals
 } // toml