Allow iterating over enum keys/values

include/cpptypesafeenum.h

@@ -13,6 +13,7 @@
 #define DECLARE_TYPESAFE_ENUM_HELPER1(name) name,
 #define DECLARE_TYPESAFE_ENUM_HELPER2(name) case TheEnum::name: return #name;
 #define DECLARE_TYPESAFE_ENUM_HELPER3(name) else if (str == CPP_STRINGIFY(name)) return TheEnum::name;
+#define DECLARE_TYPESAFE_ENUM_HELPER4(name) cb(TheEnum::name, CPP_STRINGIFY(name));
 
 #define DECLARE_TYPESAFE_ENUM(Name, Derivation, Values) \
     enum class Name Derivation \
@@ -20,7 +21,13 @@
         Values(DECLARE_TYPESAFE_ENUM_HELPER1) \
     }; \
     std::string toString(Name value); \
-    std::optional<Name> parse##Name(std::string_view str);
+    std::optional<Name> parse##Name(std::string_view str); \
+    template<typename T> \
+    void iterate##Name(T &&cb) \
+    { \
+        using TheEnum = Name; \
+        Values(DECLARE_TYPESAFE_ENUM_HELPER4) \
+    }
 
 #define IMPLEMENT_TYPESAFE_ENUM(Name, Derivation, Values) \
     std::string toString(Name value) \