Struct Result<TValue, TError>

Namespace

Badeend

Assembly

Badeend.Result.dll

Represents the result of a fallible operation.

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

[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 TError are, which we can't know at compile time. Don't want to promote the comparable stuff too much.")]
public readonly struct Result<TValue, TError> : IEquatable<Result<TValue, TError>>, IComparable<Result<TValue, TError>>, IComparable

Type Parameters

TValue

Type of the result when the operation succeeds.

TError

Type of the result when the operation fails.

Implements

IEquatable<Result<TValue, TError>>

IComparable<Result<TValue, TError>>

IComparable

Inherited Members

ValueType.Equals(object)

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Remarks

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.

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

Properties

Error

Get the error value.

public ref readonly TError Error { get; }

Property Value

TError

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, TError>)

Compare two results.

Successful results precede Error results.

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

Parameters

other Result<TValue, TError>

Returns

int

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

Exceptions

ArgumentException

TValue or TError does not implement IComparable.

Equals(Result<TValue, TError>)

Check for equality.

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

Parameters

other Result<TValue, TError>

Returns

bool

GetErrorOrDefault()

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

[Pure]
public TError? GetErrorOrDefault()

Returns

TError

GetErrorOrDefault(TError)

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

[Pure]
public TError GetErrorOrDefault(TError defaultValue)

Parameters

defaultValue TError

Returns

TError

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 TError)

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

public bool TryGetError(out TError error)

Parameters

error TError

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 TError)

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 TError error)

Parameters

value TValue

error TError

Returns

bool

Operators

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

Check for equality.

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

Parameters

left Result<TValue, TError>

right Result<TValue, TError>

Returns

bool

implicit operator Result<TValue, TError>(TValue)

Create a successful result.

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

Parameters

value TValue

Returns

Result<TValue, TError>

implicit operator Result<TValue, TError>(TError)

Create a error result.

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

Parameters

error TError

Returns

Result<TValue, TError>

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

Check for inequality.

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

Parameters

left Result<TValue, TError>

right Result<TValue, TError>

Returns

bool