Struct Result<TValue>

Namespace

Badeend

Assembly

Badeend.Result.dll

Represents the result of a fallible operation. This type is a shorthand for: Result<TValue, Badeend.Error>.

[SuppressMessage("Naming", "CA1708:Identifiers should differ by more than case", Justification = "Internal")]
[SuppressMessage("Design", "CA1036:Override methods on comparable types", Justification = "Result is only comparable if TValue and Error are, which we can't know at compile time. Don't want to promote the comparable stuff too much.")]
public readonly struct Result<TValue> : IEquatable<Result<TValue>>, IComparable<Result<TValue>>, IComparable

Type Parameters

TValue

Type of the result when the operation succeeds.

Implements

IEquatable<Result<TValue>>

IComparable<Result<TValue>>

IComparable

Inherited Members

ValueType.Equals(object)

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Extension Methods

ResultExtensions.AsGenericResult<TValue>(Result<TValue>)

Remarks

A Result can be in one of two states: Success or Error. Both states have an associated payload of type TValue or Error respectively.

Because of the implicit conversion operators you typically don't have to manually construct Results. If you do want or need to, you can use Result.Success() or Result.Error() instead.

You can examine a result like this:

_ = myResult.State switch
{
  ResultState.Success => $"Something successful: {myResult.Value}",
  ResultState.Error => $"Something failed: {myResult.Error}",
};

Or alternatively using IsSuccess, IsError, TryGetValue, TryGetError, GetValueOrDefault or GetErrorOrDefault.

Note that you should generally not attempt to derive any semantic meaning from the Error's content. This type (or its longhand form Result<T, Badeend.Error>) is semantically the same as Result<T, void> in that: all that the domain logic should care about is whether the operation succeeded or failed. The Error data is just a way to carry additional developer-oriented context.

A Result's default value is equivalent to Result.Error(default!).

Properties

Error

Get the error value.

public ref readonly Error Error { get; }

Property Value

Error

Exceptions

InvalidOperationException

The operation did not fail.

IsError

Check whether the operation failed.

[Pure]
public bool IsError { get; }

Property Value

bool

IsSuccess

Check whether the operation succeeded.

[Pure]
public bool IsSuccess { get; }

Property Value

bool

State

Get the state of the result (Success or Error).

[Pure]
public ResultState State { get; }

Property Value

ResultState

Value

Get the success value.

public ref readonly TValue Value { get; }

Property Value

TValue

Exceptions

InvalidOperationException

The operation was not successful.

Methods

CompareTo(Result<TValue>)

Compare two results.

Successful results precede Error results.

[Pure]
public int CompareTo(Result<TValue> other)

Parameters

other Result<TValue>

Returns

int

See IComparable<T>.CompareTo(T) for more information.

Exceptions

ArgumentException

TValue or TError does not implement IComparable.

Equals(Result<TValue>)

Check for equality.

[Pure]
public bool Equals(Result<TValue> other)

Parameters

other Result<TValue>

Returns

bool

GetErrorOrDefault()

Attempt to get the operation's error value. Returns default when the operation succeeded.

[Pure]
public Error GetErrorOrDefault()

Returns

Error

GetErrorOrDefault(Error)

Attempt to get the operation's error value. Returns defaultValue when the operation succeeded.

[Pure]
public Error GetErrorOrDefault(Error defaultValue)

Parameters

defaultValue Error

Returns

Error

GetHashCode()

[Pure]
public override int GetHashCode()

Returns

int

GetValueOrDefault()

Attempt to get the operation's success value. Returns default when the operation failed.

[Pure]
public TValue? GetValueOrDefault()

Returns

TValue

GetValueOrDefault(TValue)

Attempt to get the operation's success value. Returns defaultValue when the operation failed.

[Pure]
public TValue GetValueOrDefault(TValue defaultValue)

Parameters

defaultValue TValue

Returns

TValue

ToString()

Get a string representation of the result for debugging purposes. The format is not stable and may change without prior notice.

[Pure]
public override string ToString()

Returns

string

TryGetError(out Error)

Attempt to store the operation's error in error. Returns false when the operation succeeded.

public bool TryGetError(out Error error)

Parameters

error Error

Returns

bool

TryGetValue(out TValue)

Attempt to store the operation's success value in value. Returns false when the operation failed.

public bool TryGetValue(out TValue value)

Parameters

value TValue

Returns

bool

TryGetValue(out TValue, out Error)

Attempt to store the operation's success value in value. If the operation failed, this method returns false and the error is stored in error.

public bool TryGetValue(out TValue value, out Error error)

Parameters

value TValue

error Error

Returns

bool

Operators

operator ==(Result<TValue>, Result<TValue>)

Check for equality.

[Pure]
public static bool operator ==(Result<TValue> left, Result<TValue> right)

Parameters

left Result<TValue>

right Result<TValue>

Returns

bool

implicit operator Result<TValue>(Error)

Create a error result.

[Pure]
public static implicit operator Result<TValue>(Error error)

Parameters

error Error

Returns

Result<TValue>

implicit operator Result<TValue>(Result<TValue, Error>)

Convert from a Result with an explicit error type to a Result with an implicit error type.

[Pure]
[SuppressMessage("Usage", "CA2225:Operator overloads have named alternates", Justification = "Exists as extension method.")]
public static implicit operator Result<TValue>(Result<TValue, Error> result)

Parameters

result Result<TValue, Error>

Returns

Result<TValue>

implicit operator Result<TValue, Error>(Result<TValue>)

Convert from a Result with an implicit error type to a Result with an explicit error type.

[Pure]
[SuppressMessage("Usage", "CA2225:Operator overloads have named alternates", Justification = "Exists as extension method.")]
public static implicit operator Result<TValue, Error>(Result<TValue> result)

Parameters

result Result<TValue>

Returns

Result<TValue, Error>

implicit operator Result<TValue>(TValue)

Create a successful result.

[Pure]
public static implicit operator Result<TValue>(TValue value)

Parameters

value TValue

Returns

Result<TValue>

operator !=(Result<TValue>, Result<TValue>)

Check for inequality.

[Pure]
public static bool operator !=(Result<TValue> left, Result<TValue> right)

Parameters

left Result<TValue>

right Result<TValue>

Returns

bool