.. index:: pair: class; EE::Result
.. _doxid-class_e_e_1_1_result:

template class EE::Result
=========================

.. toctree::
	:hidden:

Overview
~~~~~~~~

A synchronous success-or-error value. :ref:`More...<details-class_e_e_1_1_result>`


.. ref-code-block:: cpp
	:class: doxyrest-overview-code-block

	#include <result.hpp>
	
	template <typename T, typename E>
	class Result {
	public:
		// typedefs
	
		typedef T :target:`ValueType<doxid-class_e_e_1_1_result_1a5da371900c3cd53e9486f4b16cdb9ca6>`;
		typedef E :target:`ErrorType<doxid-class_e_e_1_1_result_1a4b78f52fccaf9305662f1a19e6e9c498>`;

		// fields
	
		T :target:`mValue<doxid-class_e_e_1_1_result_1a9ce9e60c432bf7b48a32ed2783025178>`;
		E :target:`mError<doxid-class_e_e_1_1_result_1a6d4c332ad317e12d990e4ebecb1fae2b>`;

		// construction
	
		template <typename U, std::enable_if_t<std::is_constructible_v<T, U&&>, int> = 0>
		:target:`Result<doxid-class_e_e_1_1_result_1aee7d1b6c874be359de4a4822a48072aa>`(:ref:`OkValue<doxid-struct_e_e_1_1_ok_value>`<U>&& ok);
	
		template <typename U, std::enable_if_t<std::is_constructible_v<T, const U&>, int> = 0>
		:target:`Result<doxid-class_e_e_1_1_result_1a7cc092c648c7771396b566d290df4771>`(const :ref:`OkValue<doxid-struct_e_e_1_1_ok_value>`<U>& ok);
	
		template <typename G, std::enable_if_t<std::is_constructible_v<E, G&&>, int> = 0>
		:target:`Result<doxid-class_e_e_1_1_result_1ad801e1d74ce2a40e21f2a7e7ef50cf4e>`(:ref:`ErrValue<doxid-struct_e_e_1_1_err_value>`<G>&& err);
	
		template <typename G, std::enable_if_t<std::is_constructible_v<E, const G&>, int> = 0>
		:target:`Result<doxid-class_e_e_1_1_result_1a95af44aa752b4f79f2304071751f2e46>`(const :ref:`ErrValue<doxid-struct_e_e_1_1_err_value>`<G>& err);
	
		:target:`Result<doxid-class_e_e_1_1_result_1ac6da39131406e4657bf9985d7d237d39>`(const Result& other);
		:target:`Result<doxid-class_e_e_1_1_result_1add07a7d0aff6f3ce6c57427bcf5ab3ba>`(Result&& other);
		:target:`~Result<doxid-class_e_e_1_1_result_1a0f54840c68f3a6b4fd75b8adfaf4c654>`();

		// methods
	
		Result& :target:`operator=<doxid-class_e_e_1_1_result_1a60d6ad0fe534d665cd8a62ceed9a614e>`(const Result& other);
		Result& :target:`operator=<doxid-class_e_e_1_1_result_1a4d8a1e96d526524c1f863e8039008389>`(Result&& other);
		bool :target:`hasValue<doxid-class_e_e_1_1_result_1aaa6f270df2172ae74471a9995c3b5fe8>`() const;
		bool :target:`hasError<doxid-class_e_e_1_1_result_1ad165f1f775fa88eec99738f1698e4ae4>`() const;
		:target:`operator bool<doxid-class_e_e_1_1_result_1a3270621763f52b163333defacfff2232>`() const;
		T& :target:`value<doxid-class_e_e_1_1_result_1af805d5e2d121659e660f7757d7ff6e72>`();
		const T& :target:`value<doxid-class_e_e_1_1_result_1a112df1585a3cbb8bd7698a808e7e5b2d>`() const;
		T&& :target:`value<doxid-class_e_e_1_1_result_1a45998bc22bbf04aedcf102f3162ce33c>`();
		E& :target:`error<doxid-class_e_e_1_1_result_1ac79103128419357bf68f3e71e1d2c0da>`();
		const E& :target:`error<doxid-class_e_e_1_1_result_1a687a401b22fb9ca2fe7a125895b4b211>`() const;
		E&& :target:`error<doxid-class_e_e_1_1_result_1ae932eb51a0608797505eba8a7eb47e3a>`();
		T* :target:`operator-><doxid-class_e_e_1_1_result_1a765670c33e816c5eadf7edb6bac4a4af>`();
		const T* :target:`operator-><doxid-class_e_e_1_1_result_1a62cf3d67a3fb1093798ba0ca00216503>`() const;
		T& :target:`operator*<doxid-class_e_e_1_1_result_1a73953143336969dfb84f115d49edf404>`();
		const T& :target:`operator*<doxid-class_e_e_1_1_result_1a38d749fcde87bfdf36fef1e120fc6021>`() const;
		T&& :target:`operator*<doxid-class_e_e_1_1_result_1a4361905fbc0caca30c66e96a930d4cd0>`();
	};
.. _details-class_e_e_1_1_result:

Detailed Documentation
~~~~~~~~~~~~~~~~~~~~~~

A synchronous success-or-error value.

Result<T, E> holds either a T or an E, stored inline in a union. It has no threading or async semantics. Payload construction and assignment can propagate exceptions; accessing the inactive member is a contract violation reported by a debug assertion. Move-only types are supported. Assignment requires at least one alternative to be nothrow move-constructible, so a failed cross-alternative construction preserves the destination's previous alternative and value. Assignment within one alternative follows that payload's exception guarantee.

.. ref-code-block:: cpp

	Result<VFSFileInfo, VFSError> statResult = Ok( std::move( info ) );
	if ( statResult )
	    consume( statResult.value() );
	else
	    report( statResult.error() );