wanda: restructure source layoutHEADdevelop

1 files changed, 65 insertions, 0 deletions

diff --git a/source/lib/include/wanda/std_ext/optional.hpp b/source/lib/include/wanda/std_ext/optional.hpp
new file mode 100644
index 0000000..763e8ac
--- /dev/null
+++ b/source/lib/include/wanda/std_ext/optional.hpp
@@ -0,0 +1,65 @@
+/**
+ * @file   optional.hpp
+ * @author Felix Morgner (felix.morgner@gmail.com)
+ * @since  1.0.0
+ */
+
+#ifndef WANDA_STD_EXT_OPTIONAL_HPP
+#define WANDA_STD_EXT_OPTIONAL_HPP
+
+#include <optional>
+
+namespace wanda::std_ext
+{
+  /**
+   * @brief A type to represent a computation that could fail
+   */
+  struct failable
+  {
+    /**
+     * @brief A factory to create a successful computation
+     */
+    constexpr static auto success() { return failable{false}; }
+
+    /**
+     * @brief A factory to create a failed computation
+     */
+    constexpr static auto failure() { return failable{true}; }
+
+    /**
+     * @brief Execute the given handler if the computation failed
+     */
+    template<typename Handler>
+    constexpr void operator||(Handler handler) const
+    {
+      if (m_failed)
+      {
+        handler();
+      }
+    }
+
+  private:
+    constexpr explicit failable(bool failed)
+        : m_failed{failed} {};
+    bool const m_failed;
+  };
+
+  /**
+   * @brief Unwrap the given optional object, if present, and pass it to the handler
+   *
+   * @return A successful computation iff. the object was present, a failed computation otherwise.
+   */
+  template<typename ObjectType, typename HandlerType>
+  auto with(std::optional<ObjectType> && object, HandlerType handler)
+  {
+    if (object)
+    {
+      handler(object.value());
+      return failable::success();
+    }
+    return failable::failure();
+  }
+
+}  // namespace wanda::std_ext
+
+#endif
\ No newline at end of file