From 67feef558969b9819987c6e55751075b8279c347 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Sat, 1 Jun 2019 09:35:02 -0700
Subject: [PATCH] Make enable_if_t more std-like and move to fmt namespace

---
 include/fmt/core.h       | 12 ++++++++----
 include/fmt/format-inl.h |  2 +-
 include/fmt/format.h     |  2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index a733e4ef..6e73481f 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -199,6 +199,11 @@
 #endif
 
 FMT_BEGIN_NAMESPACE
+
+// An implementation of enable_if_t for pre-C++14 systems.
+template <bool B, class T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
 namespace internal {
 
 #if defined(FMT_USE_STRING_VIEW)
@@ -210,10 +215,9 @@ using std_string_view = std::experimental::basic_string_view<Char>;
 template <typename T> struct std_string_view {};
 #endif
 
-// An enable_if helper to be used in template parameters. enable_if in template
-// parameters results in much shorter symbols: https://godbolt.org/z/sWw4vP.
-template <bool B> using enable_if_t = typename std::enable_if<B, int>::type;
-#define FMT_ENABLE_IF(...) internal::enable_if_t<__VA_ARGS__> = 0
+// An enable_if helper to be used in template parameters which results in much
+// shorter symbols: https://godbolt.org/z/sWw4vP.
+#define FMT_ENABLE_IF(...) enable_if_t<__VA_ARGS__, int> = 0
 
 #if (__cplusplus >= 201703L ||                          \
      (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)) && \
diff --git a/include/fmt/format-inl.h b/include/fmt/format-inl.h
index 24c6c77b..28027a59 100644
--- a/include/fmt/format-inl.h
+++ b/include/fmt/format-inl.h
@@ -674,7 +674,7 @@ template <int GRISU_VERSION> struct grisu_shortest_handler {
   }
 };
 
-template <typename Double, enable_if_t<sizeof(Double) == sizeof(uint64_t)>>
+template <typename Double, enable_if_t<sizeof(Double) == sizeof(uint64_t), int>>
 FMT_API bool grisu_format(Double value, buffer<char>& buf, int precision,
                           unsigned options, int& exp) {
   FMT_ASSERT(value >= 0, "value is negative");
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 7e4cf3be..42846f90 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2245,7 +2245,7 @@ FMT_CONSTEXPR bool do_check_format_string(basic_string_view<Char> s,
 }
 
 template <typename... Args, typename S,
-          internal::enable_if_t<is_compile_string<S>::value>>
+          enable_if_t<is_compile_string<S>::value, int>>
 void check_format_string(S format_str) {
   typedef typename S::char_type char_t;
   FMT_CONSTEXPR_DECL bool invalid_format =