Results that can hold success (with optional success value) or an error. More...

Classes
struct	mtcore::Error< Underlying >
	A struct representing an error Auto convertible to a Result of any type. More...

struct	mtcore::Result< T, ErrType >
	Represents a Result that may have an error (error code) or a success value A type of "void" means there is no Result value, but there may be a failure. More...

struct	mtcore::Result< void, ErrType >
	Represents a Result that may have an error (error code) or a success (without a value) More...

struct	mtcore::Success< T >
	Represents a success result (auto castable to Result) More...

struct	mtcore::Success< void >
	Represents a success value. More...

Functions
template<typename T>
Success< T >	mtcore::success (const T &v)
	Creates a successful Result.

Success< void >	mtcore::success ()
	Creates a successful void Result object.

template<typename Underlying>
Error< Underlying >	mtcore::error (Underlying err)
	Creates an error.

template<typename Success, typename Acc, typename F, Iterable I, typename Err = typename decltype(std::declval<F>()( std::declval<std::remove_const_t<typename decltype(std::declval<I>().iter())::IterElem>>()))::Err>
Result< Success, Err >	mtcore::results::accumulate (Success initial, const Acc &acc, const F &func, const I &iterable)
	Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

template<typename F, Iterable I, typename Err = typename decltype(std::declval<F>()( std::declval<std::remove_const_t<typename decltype(std::declval<I>().iter())::IterElem>>()))::Err>
Result< void, Err >	mtcore::results::foreach (const F &func, const I &iterable)
	Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

template<typename F, typename... Args, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>
Result< void, Err >	mtcore::results::chain (const F &func, const Args &...args)
	Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

template<typename Success, typename Acc, typename F, typename... Args, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>
Result< Success, Err >	mtcore::results::reduce (Success initVal, const Acc &acc, const F &func, const Args &...args)
	Reduces arguments with errorable function If an error is encountered, execution will stop and immediately return The accumulated Result will be what's returned on success Useful for reduction/mapping.

template<typename F, typename... Args, typename Out = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Value, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>
auto	mtcore::results::map (const F &func, const Args &...args)
	Maps values with function that may error.

Detailed Description

Results that can hold success (with optional success value) or an error.

Meant to replace exception throwing

Function Documentation

◆ accumulate()

template<typename Success, typename Acc, typename F, Iterable I, typename Err = typename decltype(std::declval<F>()( std::declval<std::remove_const_t<typename decltype(std::declval<I>().iter())::IterElem>>()))::Err>

Result< Success, Err > mtcore::results::accumulate	(	Success	initial,
		const Acc &	acc,
		const F &	func,
		const I &	iterable )

Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

Template Parameters

F	Type of function to execute
I	Type Iterable to operate on
Err	Type of Result Error

Parameters

func	Function to execute
iterable	Iterable to execute function on

Returns: Result of success or error

Definition at line 453 of file result.hpp.

                                                                                                     {
    auto iter  = iterable.iter();
    using Elem = std::remove_cv_t<typename decltype(iter)::IterElem>;
    Elem cur;
    while (iter.next().move_if_present(cur)) {
      auto res = func(cur);
      if (res.is_error()) {
        return res.error();
      }
      initial = acc(initial, res.value());
    }
    return success(initial);
  }

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◆ chain()

template<typename F, typename... Args, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>

Result< void, Err > mtcore::results::chain	(	const F &	func,
		const Args &...	args )

Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

Template Parameters

F	Type of function to execute
Args	Type of variadic arguments
Err	Type of Result Error

Parameters

func	Function to execute
args	Arguments to execute function on

Returns: Result of success or error

Definition at line 539 of file result.hpp.

                                                              {
    return impl::Chain<Err, F, Args...>::run(func, args...);
  }

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◆ error()

template<typename Underlying>

Error< Underlying > mtcore::error ( Underlying err )

Creates an error.

Template Parameters

Underlying Error underlying type

Parameters

err	Error data

Returns: An error

Definition at line 425 of file result.hpp.

                                          {
    return Error<Underlying>{err};
  }

◆ foreach()

template<typename F, Iterable I, typename Err = typename decltype(std::declval<F>()( std::declval<std::remove_const_t<typename decltype(std::declval<I>().iter())::IterElem>>()))::Err>

Result< void, Err > mtcore::results::foreach	(	const F &	func,
		const I &	iterable )

Chains together the execution of an errorable function on a list of arguments If an error is encountered, execution will stop and immediately return No Result value is returned Useful for performing side effects.

Template Parameters

F	Type of function to execute
I	Type Iterable to operate on
Err	Type of Result Error

Parameters

func	Function to execute
iterable	Iterable to execute function on

Returns: Result of success or error

Definition at line 483 of file result.hpp.

                                                               {
    auto iter  = iterable.iter();
    using Elem = std::remove_cv_t<typename decltype(iter)::IterElem>;
    Elem cur;
    while (iter.next().move_if_present(cur)) {
      auto res = func(cur);
      if (res.is_error()) {
        return res.error();
      }
    }
    return success();
  }

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◆ map()

template<typename F, typename... Args, typename Out = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Value, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>

auto mtcore::results::map	(	const F &	func,
		const Args &...	args )

Maps values with function that may error.

Results are put into a tuple If an error is encountered, execution will stop and immediately return

Template Parameters

F	Function to map with
Args	Arguments to map
Out	Type of success output
Err	Type of error in Result

Parameters

func	Function to use to map objects
args	Arguments to map

Returns: Tuple of mapped success values on success, or error on failure

Definition at line 585 of file result.hpp.

                                               {
    return impl::Map<Out, Err, F, Args...>::run(func, args...);
  }

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◆ reduce()

template<typename Success, typename Acc, typename F, typename... Args, typename Err = typename decltype(std::declval<F>()(std::declval<typename impl::FirstVariadic<Args...>::Type>()))::Err>

Result< Success, Err > mtcore::results::reduce	(	Success	initVal,
		const Acc &	acc,
		const F &	func,
		const Args &...	args )

Reduces arguments with errorable function If an error is encountered, execution will stop and immediately return The accumulated Result will be what's returned on success Useful for reduction/mapping.

Template Parameters

Success	Final Result type on success
F	Errorable function to map each element through
Acc	Accumulator which takes current accumulated value and success Result from F (only success value, not full Result object)
Args	Arguments to reduce over
Err	Result error type (auto inferred)

Parameters

initVal	Initial value to start accumulation with
acc	Function to accumulate with
func	Function that may err
args	Arguments to reduce over

Returns: Final Result

Definition at line 564 of file result.hpp.

                                                                                                   {
    return impl::Reduce<F, Acc, Args...>::template run<Success, Err>(initVal, func, acc, args...);
  }

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◆ success() [1/2]

Success< void > mtcore::success ( )

inline

Creates a successful void Result object.

Returns: Result

Definition at line 398 of file result.hpp.

398{ return {}; }

◆ success() [2/2]

template<typename T>

Success< T > mtcore::success ( const T & v )

Creates a successful Result.

Template Parameters

T	Type of successful Result (inferrable)

Parameters

v	Successful value

Returns: Result

Definition at line 389 of file result.hpp.

                                 {
    return Success<T>{v};
  }

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Classes

Functions

Detailed Description

Function Documentation

◆ accumulate()

◆ chain()

◆ error()

◆ foreach()

◆ map()

◆ reduce()

◆ success() [1/2]

◆ success() [2/2]