Added result type and stacktrace capabilities.

source/mijin/types/result.hpp

@@ -0,0 +1,75 @@
+
+#pragma once
+
+#if !defined(MIJIN_TYPES_RESULT_HPP_INCLUDED)
+#define MIJIN_TYPES_RESULT_HPP_INCLUDED 1
+
+#include <string>
+#include <variant>
+
+namespace mijin
+{
+
+//
+// public defines
+//
+
+//
+// public constants
+//
+
+//
+// public types
+//
+
+template<typename TSuccess, typename TError>
+class ResultBase
+{
+private:
+    struct Empty {};
+
+    std::variant<Empty, TSuccess, TError> state_;
+public:
+    ResultBase() = default;
+    ResultBase(const ResultBase&) = default;
+    ResultBase(ResultBase&&) = default;
+    ResultBase(TSuccess successValue) noexcept : state_(std::move(successValue)) {}
+    ResultBase(TError errorValue) noexcept : state_(std::move(errorValue)) {}
+
+    ResultBase& operator=(const ResultBase&) = default;
+    ResultBase& operator=(ResultBase&&) = default;
+
+    bool operator==(const ResultBase& other) const noexcept { return state_ == other.state_; }
+    bool operator!=(const ResultBase& other) const noexcept { return state_ != other.state_; }
+    operator bool() const noexcept { return isSuccess(); }
+    bool operator!() const noexcept { return !isSuccess(); }
+    TSuccess& operator*() noexcept { return getValue(); }
+    const TSuccess& operator*() const noexcept { return getValue(); }
+    TSuccess* operator->() noexcept { return &getValue(); }
+    const TSuccess* operator->() const noexcept { return &getValue(); }
+
+    [[nodiscard]] bool isEmpty() const noexcept { return std::holds_alternative<Empty>(state_); }
+    [[nodiscard]] bool isSuccess() const noexcept { return std::holds_alternative<TSuccess>(state_); }
+    [[nodiscard]] bool isError() const noexcept { return std::holds_alternative<TError>(state_); }
+
+    [[nodiscard]] TSuccess& getValue() noexcept { return std::get<TSuccess>(state_); }
+    [[nodiscard]] TError& getError() noexcept { return std::get<TError>(state_); }
+    [[nodiscard]] const TSuccess& getValue() const noexcept { return std::get<TSuccess>(state_); }
+    [[nodiscard]] const TError& getError() const noexcept { return std::get<TError>(state_); }
+};
+
+struct ResultError
+{
+    std::string message;
+};
+
+template<typename TSuccess>
+using Result = ResultBase<TSuccess, ResultError>;
+
+//
+// public functions
+//
+
+} // namespace mijin
+
+#endif // !defined(MIJIN_TYPES_RESULT_HPP_INCLUDED)