Add enchantum as an enum reflection backend (#441)

---------

Co-authored-by: Dr. Patrick Urbanke <[email protected]>

Author: ZXShady

README.md

@@ -584,3 +584,5 @@ reflect-cpp is released under the MIT License. Refer to the LICENSE file for det
 reflect-cpp includes [YYJSON](https://github.com/ibireme/yyjson), the fastest JSON library currently in existence. YYJSON is written by YaoYuan and also released under the MIT License.
 
 reflect-cpp includes [compile-time-regular-expressions](https://github.com/hanickadot/compile-time-regular-expressions). CTRE is written by Hana Dusíková and released under the Apache-2.0 License with LLVM exceptions.
+
+reflect-cpp includes [enchantum](https://github.com/ZXShady/enchantum/tree/main). enchantum is written by ZXShady and also released under the MIT License.

docs/enums.md

@@ -1,6 +1,6 @@
 # Enums
 
-reflect-cpp supports scoped enumerations. They can either come in the form of normal enumerations or flag enums.
+reflect-cpp supports both scoped and unscoped enumerations as long as they are named. They can either come in the form of normal enumerations or flag enums.
 
 ## Normal enumerations
 
@@ -27,21 +27,24 @@ This results in the following JSON string:
 
 However, some limitations apply:
 
-1. They must be scoped enumerations.
+1. They cannot be unnamed enumerations.
 
     ```cpp
-    /// OK - scoped enumeration
+    // OK - scoped enumeration
     enum class Color1 { red, green, blue, yellow };
 
-    /// OK - scoped enumeration
+    // OK - scoped enumeration
     enum struct Color2 { red, green, blue, yellow };
 
-    /// unsupported - unscoped enumerations
+    // OK - unscoped enumeration
     enum Color3 { red, green, blue, yellow };
+
+    /// Unsupported: Anonymous enumeration
+    enum { red, green, blue, yellow };
     ```
 
 2. Enum values must be in the range `[RFL_ENUM_RANGE_MIN, RFL_ENUM_RANGE_MAX]`. If the range is not specified, the
-   default range is `[0, 127]`.
+   default range is `[-256, 256]`.
 
     - You can specify a custom range for the all enum values by defining `RFL_ENUM_RANGE_MIN` and `RFL_ENUM_RANGE_MAX`
       before including the reflect-cpp header:

include/rfl/config.hpp

@@ -0,0 +1,19 @@
+#ifndef RFL_CONFIG_HPP_
+#define RFL_CONFIG_HPP_
+
+namespace rfl::config {
+
+// To specify a different range for a particular enum type, specialize the
+// enum_range template for that enum type.
+template <typename T>
+struct enum_range {
+  // In your template specialization, uncomment these two lines and replace them
+  // with the values of your choice.
+  // static constexpr int min = ...;
+  // static constexpr int max = ...;
+};
+
+}  // namespace rfl::config
+
+#endif
+

include/rfl/enums.hpp

@@ -4,69 +4,113 @@
 #include <string>
 
 #include "Result.hpp"
-#include "internal/enums/StringConverter.hpp"
 #include "internal/enums/get_enum_names.hpp"
-#include "internal/enums/is_flag_enum.hpp"
-#include "internal/enums/is_scoped_enum.hpp"
+#include "internal/strings/strings.hpp"
+#include "thirdparty/enchantum/enchantum.hpp"
+#include "thirdparty/enchantum/bitflags.hpp"
 
 namespace rfl {
 
-// Converts an enum value to a string.
-template <internal::enums::is_scoped_enum EnumType>
-std::string enum_to_string(EnumType _enum) {
-  return rfl::internal::enums::StringConverter<EnumType>::enum_to_string(_enum);
+template <enchantum::Enum EnumType>
+std::string enum_to_string(const EnumType _enum) {
+  const auto to_string_or_number = [](const EnumType e) {
+    const auto s = enchantum::to_string(e);
+    return s.empty() ? std::to_string(
+                           static_cast<std::underlying_type_t<EnumType>>(e))
+                     : std::string(s);
+  };
+
+  if constexpr (enchantum::is_bitflag<EnumType>) {
+    // Iterates through the enum bit by bit and matches it against the flags.
+    using T = std::underlying_type_t<EnumType>;
+    auto val = static_cast<T>(_enum);
+    int i = 0;
+    std::vector<std::string> flags;
+    while (val != 0) {
+      const auto bit = val & static_cast<T>(1);
+      if (bit == 1) {
+        auto str =
+            to_string_or_number(static_cast<EnumType>(static_cast<T>(1) << i));
+        flags.emplace_back(std::move(str));
+      }
+      ++i;
+      val >>= 1;
+    }
+    return internal::strings::join("|", flags);
+  } else {
+    return to_string_or_number(_enum);
+  }
 }
 
 // Converts a string to a value of the given enum type.
-template <internal::enums::is_scoped_enum EnumType>
-rfl::Result<EnumType> string_to_enum(const std::string& _str) {
-  return rfl::internal::enums::StringConverter<EnumType>::string_to_enum(_str);
+template <enchantum::Enum EnumType>
+Result<EnumType> string_to_enum(const std::string& _str) {
+  const auto cast_numbers_or_names =
+      [](const std::string& name) -> Result<EnumType> {
+    const auto r = enchantum::cast<EnumType>(name);
+    if (r) return *r;
+    try {
+      return static_cast<EnumType>(std::stoi(name));
+    } catch (std::exception& exp) {
+      return error(exp.what());
+    }
+  };
+
+  if constexpr (enchantum::is_bitflag<EnumType>) {
+    using T = std::underlying_type_t<EnumType>;
+    const auto split = internal::strings::split(_str, "|");
+    auto res = static_cast<T>(0);
+    for (const auto& s : split) {
+      const auto r = cast_numbers_or_names(s);
+      if (r) {
+        res |= static_cast<T>(*r);
+      } else {
+        return r;
+      }
+    }
+    return static_cast<EnumType>(res);
+  } else {
+    return cast_numbers_or_names(_str);
+  }
 }
 
 // Returns a named tuple mapping names of enumerators of the given enum type to
 // their values.
-template <internal::enums::is_scoped_enum EnumType>
+template <enchantum::Enum EnumType>
 auto get_enumerators() {
-  constexpr auto names = internal::enums::get_enum_names<
-      EnumType, internal::enums::is_flag_enum<EnumType>>();
-  return internal::enums::names_to_enumerator_named_tuple(names);
+  return internal::enums::names_to_enumerator_named_tuple(
+      internal::enums::get_enum_names<EnumType>());
 }
 
 // Returns a named tuple mapping names of enumerators of the given enum type to
 // their underlying values.
-template <internal::enums::is_scoped_enum EnumType>
+template <enchantum::Enum EnumType>
 auto get_underlying_enumerators() {
-  constexpr auto names = internal::enums::get_enum_names<
-      EnumType, internal::enums::is_flag_enum<EnumType>>();
-  return internal::enums::names_to_underlying_enumerator_named_tuple(names);
+  return internal::enums::names_to_underlying_enumerator_named_tuple(
+      internal::enums::get_enum_names<EnumType>());
 }
 
 // Returns an std::array containing pairs of enumerator names (as
 // std::string_view) and values.
-template <internal::enums::is_scoped_enum EnumType>
+template <enchantum::Enum EnumType>
 constexpr auto get_enumerator_array() {
-  constexpr auto names = internal::enums::get_enum_names<
-      EnumType, internal::enums::is_flag_enum<EnumType>>();
-  return internal::enums::names_to_enumerator_array(names);
+  return internal::enums::names_to_enumerator_array(
+      internal::enums::get_enum_names<EnumType>());
 }
 
 // Returns an std::array containing pairs of enumerator names (as
 // std::string_view) and underlying values.
-template <internal::enums::is_scoped_enum EnumType>
+template <enchantum::Enum EnumType>
 constexpr auto get_underlying_enumerator_array() {
-  constexpr auto names = internal::enums::get_enum_names<
-      EnumType, internal::enums::is_flag_enum<EnumType>>();
-  return internal::enums::names_to_underlying_enumerator_array(names);
+  return internal::enums::names_to_underlying_enumerator_array(
+      internal::enums::get_enum_names<EnumType>());
 }
 
 // Returns the range of the given enum type as a pair of the minimum and maximum
-template <internal::enums::is_scoped_enum EnumType>
+template <enchantum::Enum EnumType>
 constexpr auto get_enum_range() {
-  return std::make_pair(
-      internal::enums::get_range_min<EnumType,
-                                     internal::enums::is_flag_enum<EnumType>>(),
-      internal::enums::get_range_max<
-          EnumType, internal::enums::is_flag_enum<EnumType>>());
+  return std::make_pair(enchantum::enum_traits<EnumType>::min,
+                        enchantum::enum_traits<EnumType>::max);
 }
 
 }  // namespace rfl

include/rfl/internal/enums/Names.hpp

@@ -9,94 +9,27 @@
 #include <utility>
 
 #include "../../Literal.hpp"
+#include "../../config.hpp"
 #include "../../define_literal.hpp"
 #include "../../make_named_tuple.hpp"
+#include "../../thirdparty/enchantum/enchantum.hpp"
 #include "../StringLiteral.hpp"
 
-namespace rfl {
-
-// Enum values must be greater than or equal to RFL_ENUM_RANGE_MIN.
-// By default, RFL_ENUM_RANGE_MIN is set to 0.
-// To change the default minimum range for all enum types, redefine the macro
-// RFL_ENUM_RANGE_MIN.
-#if !defined(RFL_ENUM_RANGE_MIN)
-#define RFL_ENUM_RANGE_MIN 0
-#endif
-
-// Enum values must be less than or equal to RFL_ENUM_RANGE_MAX.
-// By default, RFL_ENUM_RANGE_MAX is set to 127.
-// To change the default maximum range for all enum types, redefine the macro
-// RFL_ENUM_RANGE_MAX.
-#if !defined(RFL_ENUM_RANGE_MAX)
-#define RFL_ENUM_RANGE_MAX 127
-#endif
-
-namespace config {
-
-// To specify a different range for a particular enum type, specialize the
-// enum_range template for that enum type.
-template <typename T>
-struct enum_range {
-  static constexpr int min = RFL_ENUM_RANGE_MIN;
-  static constexpr int max = RFL_ENUM_RANGE_MAX;
-};
-}  // namespace config
-
-namespace internal {
-namespace enums {
-
-static_assert(RFL_ENUM_RANGE_MAX > RFL_ENUM_RANGE_MIN,
-              "RFL_ENUM_RANGE_MAX must be greater than RFL_ENUM_RANGE_MIN.");
-
-template <typename T, typename = void>
-struct range_min : std::integral_constant<int, RFL_ENUM_RANGE_MIN> {};
-
-template <typename T>
-struct range_min<T, std::void_t<decltype(config::enum_range<T>::min)>>
-    : std::integral_constant<decltype(config::enum_range<T>::min),
-                             config::enum_range<T>::min> {};
-
-template <typename T, typename = void>
-struct range_max : std::integral_constant<int, RFL_ENUM_RANGE_MAX> {};
-
-template <typename T>
-struct range_max<T, std::void_t<decltype(config::enum_range<T>::max)>>
-    : std::integral_constant<decltype(config::enum_range<T>::max),
-                             config::enum_range<T>::max> {};
+namespace rfl::internal::enums {
 
 template <class EnumType, class LiteralType, size_t N, bool _is_flag,
-          auto... _enums>struct Names {
+          auto... _enums>
+struct Names {
   /// Contains a collection of enums as compile-time strings.
   using Literal = LiteralType;
 
   /// The number of possible values
   constexpr static size_t size = N;
 
   /// A list of all the possible enums
-  constexpr static std::array<EnumType, N> enums_ =
-      std::array<EnumType, N>{_enums...};
-
-  static_assert(N == 0 || LiteralType::size() == N,
-                "Size of literal and enum do not match.");
-
-  template <class NewLiteral, auto _new_enum>
-  using AddOneType = std::conditional_t<
-      N == 0, Names<EnumType, NewLiteral, 1, _is_flag, _new_enum>,
-      Names<EnumType, define_literal_t<LiteralType, NewLiteral>, N + 1,
-            _is_flag, _enums..., _new_enum>>;
+  constexpr static auto enums_ = std::array<EnumType, N>{_enums...};
 };
 
-
-template <class EnumType, class LiteralType1, size_t N1, bool _is_flag1,
-          auto... _enums1, class LiteralType2, size_t N2, auto... _enums2>
-consteval auto operator|(
-    Names<EnumType, LiteralType1, N1, _is_flag1, _enums1...>,
-    Names<EnumType, LiteralType2, N2, _is_flag1, _enums2...>) {
-  using CombinedLiteral = define_literal_t<LiteralType1, LiteralType2>;
-  return Names<EnumType, CombinedLiteral, N1 + N2, _is_flag1,
-              _enums1..., _enums2...>{};
-}
-
 template <class EnumType, size_t N, bool _is_flag, StringLiteral... _names,
           auto... _enums>
 auto names_to_enumerator_named_tuple(
@@ -132,8 +65,7 @@ names_to_underlying_enumerator_array(
                      static_cast<std::underlying_type_t<EnumType>>(_enums))...};
 }
 
-}  // namespace enums
-}  // namespace internal
-}  // namespace rfl
+}  // namespace rfl::internal::enums
 
 #endif
+