Add monadic mapping function to coral::optional

source/coral.cpp

@@ -2,6 +2,7 @@ module;
 
 #include <cstdint>
 #include <cstddef>
+#include <type_traits>
 
 export module coral;
 
@@ -296,6 +297,17 @@ export namespace coral {
 			return this->buffer[sizeof(element)] == 1;
 		}
 
+		/**
+		 * Attempts to call `apply` on the contained value, returning a new [optional] of whatever type `apply` returns.
+		 *
+		 * If the optional is empty, an empty optional will always be returned.
+		 */
+		template<typename functor> std::invoke_result_t<functor, element> map(functor const & apply) const {
+			if (this->has_value()) return apply(this->value());
+
+			return {};
+		}
+
 		/**
 		 * Returns the contained value or `fallback` if the optional is empty.
 		 */