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Diffstat (limited to 'source/include/wanda/optional.hpp')
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1 files changed, 65 insertions, 0 deletions
diff --git a/source/include/wanda/optional.hpp b/source/include/wanda/optional.hpp new file mode 100644 index 0000000..da3774c --- /dev/null +++ b/source/include/wanda/optional.hpp @@ -0,0 +1,65 @@ +/** + * @file optional.hpp + * @author Felix Morgner (felix.morgner@gmail.com) + * @since 1.0.0 + */ + +#ifndef WANDA_OPTIONAL_HPP +#define WANDA_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
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