1 files changed, 18 insertions, 0 deletions
diff --git a/src/utils.h b/src/utils.h
index 005e5be..77096e7 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -7,6 +7,7 @@
 #include <map>
 #include <sstream>
 #include <memory>
+#include <optional>
 #include <stdexcept>
 #include <filesystem>
 
@@ -23,6 +24,23 @@ namespace nlohmann {
             opt = std::shared_ptr<T>(T::create(j));
         }
     };
+
+    template <typename T> struct adl_serializer<std::optional<T>> {
+        static void to_json(json& j, const std::optional<T>& opt) {
+            if(opt) {
+                j = *opt;
+            } else {
+                j = nullptr;
+            }
+        }
+        static void from_json(const json& j, std::optional<T>& opt) {
+            if(j.is_null()) {
+                opt = std::optional<T>();
+            } else {
+                opt = j.get<T>();
+            }
+        }
+    };
 }
 
 namespace utils {