From 330935c1d679d45060df6e71d557561f18260cc6 Mon Sep 17 00:00:00 2001
From: jaskij <jaskij@gmail.com>
Date: Sat, 10 Feb 2024 17:49:05 +0100
Subject: [PATCH] better_enum::optional: add conversion operator to
 std::optional

---
 enum.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/enum.h b/enum.h
index c89804b..b533744 100644
--- a/enum.h
+++ b/enum.h
@@ -14,6 +14,10 @@
 #include <iosfwd>
 #include <stdexcept>
 
+#if __cplusplus >= 201703L
+#include <optional>
+#endif
+
 
 // in-line, non-#pragma warning handling
 // not supported in very old compilers (namely gcc 4.4 or less)
@@ -344,6 +348,13 @@ struct optional {
 
     BETTER_ENUMS_CONSTEXPR_ const T& value() const { return _value; }
 
+    #if defined(__cpp_lib_optional) && (__cpp_lib_optional >= 201606L)
+    BETTER_ENUMS_CONSTEXPR_ operator std::optional<T>() const {
+        if(has_value()) {return {_value};}
+        return std::nullopt;
+    }
+    #endif
+
   private:
     bool    _valid;
     T       _value;