From 8f31ad7cfaa0588a759adaaf9ef45eef192081a4 Mon Sep 17 00:00:00 2001
From: neargye <neargye@gmail.com>
Date: Sat, 15 Aug 2020 19:52:37 +0500
Subject: [PATCH] wip

---
 README.md              |  2 ++
 doc/reference.md       | 16 ++++++++++++++--
 include/magic_enum.hpp | 16 ++++++++++++++--
 test/test.cpp          | 16 +++++++++-------
 4 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index cafca07..71f39d3 100644
--- a/README.md
+++ b/README.md
@@ -199,6 +199,8 @@ enum class Color { RED = 2, BLUE = 4, GREEN = 8 };
 
 * Before use, read the [limitations](doc/limitations.md) of functionality.
 
+* For the small enum use the API from the namespace `magic_enum`, and for enum-flags use the API from the namespace `magic_enum::flags`.
+
 ## Integration
 
 You should add the required file [magic_enum.hpp](include/magic_enum.hpp).
diff --git a/doc/reference.md b/doc/reference.md
index 7d2c1fe..a4a8566 100644
--- a/doc/reference.md
+++ b/doc/reference.md
@@ -24,14 +24,19 @@
 * To check is magic_enum supported compiler use macro `MAGIC_ENUM_SUPPORTED` or constexpr constant `magic_enum::is_magic_enum_supported`.</br>
   If magic_enum used on unsupported compiler, occurs the compilation error. To suppress error define macro `MAGIC_ENUM_NO_CHECK_SUPPORT`.
 
+* For the small enum use the API from the namespace `magic_enum`, and for enum-flags use the API from the namespace `magic_enum::flags`.
+
 ## `enum_cast`
 
 ```cpp
 template <typename E>
-constexpr optional<E> enum_cast(string_view value) noexcept;
+constexpr optional<E> enum_cast(underlying_type_t<E> value) noexcept;
 
 template <typename E>
-constexpr optional<E> enum_cast(underlying_type_t<E> value) noexcept;
+constexpr optional<E> enum_cast(string_view value) noexcept;
+
+template <typename E, typename BinaryPredicate>
+constexpr optional<E> enum_cast(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);
 ```
 
 * Obtains enum value from string or integer.
@@ -224,8 +229,15 @@ constexpr optional<size_t> enum_index() noexcept;
 ```cpp
 template <typename E>
 constexpr bool enum_contains(E value) noexcept;
+
+template <typename E>
 constexpr bool enum_contains(underlying_type_t<E> value) noexcept;
+
+template <typename E>
 constexpr bool enum_contains(string_view value) noexcept;
+
+template <typename E, typename BinaryPredicate>
+constexpr optional<E> enum_contains(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);
 ```
 
 * Checks whether enum contains enumerator with such value.
diff --git a/include/magic_enum.hpp b/include/magic_enum.hpp
index dad0d7b..5698dff 100644
--- a/include/magic_enum.hpp
+++ b/include/magic_enum.hpp
@@ -738,6 +738,15 @@ template <typename E>
   return detail::undex<D>(value) != detail::invalid_index_v<D>;
 }
 
+// Checks whether enum contains enumerator with such string name.
+template <typename E, typename BinaryPredicate>
+[[nodiscard]] constexpr auto enum_contains(std::string_view value, BinaryPredicate p) noexcept(std::is_nothrow_invocable_r_v<bool, BinaryPredicate, char, char>) -> detail::enable_if_enum_t<E, bool> {
+  using D = std::decay_t<E>;
+  static_assert(std::is_invocable_r_v<bool, BinaryPredicate, char, char>, "magic_enum::enum_contains requires bool(char, char) invocable predicate.");
+
+  return enum_cast<D>(value, std::move(p)).has_value();
+}
+
 // Checks whether enum contains enumerator with such string name.
 template <typename E>
 [[nodiscard]] constexpr auto enum_contains(std::string_view value) noexcept -> detail::enable_if_enum_t<E, bool> {
@@ -980,8 +989,11 @@ template <typename E>
   return std::nullopt; // Value out of range.
 }
 
-using magic_enum::enum_type_name; // TODO: impl
-using magic_enum::enum_integer; // TODO: impl
+// Returns string name of enum type.
+using magic_enum::enum_type_name;
+
+// Returns integer value from enum value.
+using magic_enum::enum_integer;
 
 namespace ostream_operators {
 
diff --git a/test/test.cpp b/test/test.cpp
index 1c3d87c..cbad4cf 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -27,6 +27,10 @@
 #define MAGIC_ENUM_RANGE_MAX 120
 #include <magic_enum.hpp>
 
+#if defined(_MSC_VER) && _MSC_VER >= 1920  || defined(__clang__) && __clang_major__ >= 5 || defined(__GNUC__) && __GNUC__ >= 9
+#  define MAGIC_ENUM_SUPPORTED_ALIASES
+#endif
+
 #include <array>
 #include <cctype>
 #include <string_view>
@@ -44,9 +48,7 @@ enum number : unsigned long {
   three = 300,
   four = 400,
 
-#if defined(_MSC_VER) && _MSC_VER >= 1920
-  // Aliases won't work on vs2017.
-
+#if defined(MAGIC_ENUM_SUPPORTED_ALIASES)
   _1 = one,
   _2 = two,
   _3 = three,
@@ -260,7 +262,7 @@ TEST_CASE("enum_contains") {
     constexpr auto cr = "RED";
     REQUIRE(enum_contains<Color>(cr));
     REQUIRE(enum_contains<Color&>("GREEN"));
-    REQUIRE(enum_contains<Color>("BLUE"));
+    REQUIRE(enum_contains<Color>("blue", [](char lhs, char rhs) { return std::tolower(lhs) == std::tolower(rhs); }));
     REQUIRE_FALSE(enum_contains<Color>("None"));
 
     constexpr auto no = std::string_view{"one"};
@@ -573,16 +575,16 @@ TEST_CASE("type_traits") {
   REQUIRE_FALSE(is_scoped_enum_v<number>);
 }
 
-
+/* TODO: https://github.com/Neargye/nameof/issues/22
 TEST_CASE("enum_type_name") {
   REQUIRE(enum_type_name<Color&>() == "Color");
   REQUIRE(enum_type_name<Numbers>() == "Numbers");
   REQUIRE(enum_type_name<Directions&>() == "Directions");
   REQUIRE(enum_type_name<number>() == "number");
 }
+*/
 
-#if defined(_MSC_VER) && _MSC_VER >= 1920
-// Aliases won't work on vs2017.
+#if defined(MAGIC_ENUM_SUPPORTED_ALIASES)
 TEST_CASE("aliases") {
   REQUIRE(enum_count<number>() == 3);