Class ResultExtensions

Namespace

Rascal

Assembly

Rascal.dll

Extensions for or relating to Result<T>.

public static class ResultExtensions

Inheritance

object

ResultExtensions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Methods

CatchCancellation<T>(Task<T>, Func<Error>?)

Catches the cancellation of a task and wraps the returned value or thrown exception in a result.

public static Task<Result<T>> CatchCancellation<T>(this Task<T> task, Func<Error>? error = null)

Parameters

task Task<T>

The task to catch.

error Func<Error>

A function which produces an error in case of a cancellation.

Returns

Task<Result<T>>

A result which contains either the value returned by awaiting task, or an error in case the task is cancelled.

Type Parameters

T

The type returned by the task.

GetValueOrNull<T>(Result<T>)

Gets the ok value of the result, or null if the result is an error.

[Pure]
public static T? GetValueOrNull<T>(this Result<T> result) where T : struct

Parameters

result Result<T>

The result to get the ok value of.

Returns

T?

The ok value of result, or null if result is an error.

Type Parameters

T

The type of the ok value of the result.

Remarks

This method differs from GetValueOrDefault() in that it specifically targets value types and returns null as opposed to the default value for the type in case the result is an error. Can also be understood as mapping the value to T? and calling GetValueOrDefault() on the returned result.

Index<T>(IReadOnlyList<T>, int, Error?)

Gets a result containing the element at the specified index in the list, or an error if the index is out of range of the list.

public static Result<T> Index<T>(this IReadOnlyList<T> list, int index, Error? error = null)

Parameters

list IReadOnlyList<T>

The list to index.

index int

The zero-based index of the element to get.

error Error

The error to return if the index is out of range.

Returns

Result<T>

A result containing the value at index in the list, or an error if the index is out of range of the list.

Type Parameters

T

The type of the elements in the list.

NotNull<T>(T?, Error?)

Turns a nullable value into a result containing a non-null ok value or an error if the value is null.

[Pure]
public static Result<T> NotNull<T>(this T? x, Error? error = null) where T : struct

Parameters

x T?

The value to turn into a result.

error Error

The error to return if the value is null.

Returns

Result<T>

A result containing x if it is not null, or otherwise error.

Type Parameters

T

The type of the value.

Remarks

Note that this method has two variants: one for reference types and one for nullable value types.

NotNull<T>(T?, Error?)

Turns a nullable value into a result containing a non-null ok value or an error if the value is null.

[Pure]
public static Result<T> NotNull<T>(this T? x, Error? error = null) where T : class

Parameters

x T

The value to turn into a result.

error Error

The error to return if the value is null.

Returns

Result<T>

A result containing x if it is not null, or otherwise error.

Type Parameters

T

The type of the value.

Remarks

Note that this method has two variants: one for reference types and one for nullable value types.

Sequence<T>(IEnumerable<Result<T>>)

Turns a sequence of results into a single result containing the ok values in the results only if all the results are ok. Can also been seen as turning an IEnumerable<Result<T>> "inside out".

public static Result<IReadOnlyList<T>> Sequence<T>(this IEnumerable<Result<T>> results)

Parameters

results IEnumerable<Result<T>>

The results to turn into a single sequence.

Returns

Result<IReadOnlyList<T>>

A single result containing a sequence of all the ok values from the original sequence of results, or the first error encountered within the sequence.

Type Parameters

T

The type of the ok values in the results.

Remarks

This method completely enumerates the input sequence before returning and is not lazy. As a consequence of this, the sequence within the returned result is an IReadOnlyList<T>.

ToString<T>(Result<T>, IFormatProvider)

Returns a string representation of the result using a specified IFormatProvider to format an ok value.

public static string ToString<T>(this Result<T> result, IFormatProvider formatProvider) where T : IFormattable

Parameters

result Result<T>

The result to return a string representation of.

formatProvider IFormatProvider

The provider to use to format the ok value.

Returns

string

Extensions for or relating to .

Type Parameters

T

The type of the ok value in the result.

ToString<T>(Result<T>, string)

Returns a string representation of the result using a specified format to format an ok value.

public static string ToString<T>(this Result<T> result, string format) where T : IFormattable

Parameters

result Result<T>

The result to return a string representation of.

format string

The format to use.

Returns

string

Extensions for or relating to .

Type Parameters

T

The type of the ok value in the result.

ToString<T>(Result<T>, string?, IFormatProvider?)

Returns a string representation of the result using a specified format and IFormatProvider to format an ok value.

public static string ToString<T>(this Result<T> result, string? format, IFormatProvider? formatProvider) where T : IFormattable

Parameters

result Result<T>

The result to return a string representation of.

format string

The format to use.

formatProvider IFormatProvider

The provider to use to format the ok value.

Returns

string

Extensions for or relating to .

Type Parameters

T

The type of the ok value in the result.

TryGetValueR<TKey, TValue>(IReadOnlyDictionary<TKey, TValue>, TKey, Error?)

Gets a result containing the value that is associated with the specified key in a dictionary, or an error if the key is not present.

public static Result<TValue> TryGetValueR<TKey, TValue>(this IReadOnlyDictionary<TKey, TValue> dict, TKey key, Error? error = null)

Parameters

dict IReadOnlyDictionary<TKey, TValue>

The dictionary to try locate the key in.

key TKey

The key to locate.

error Error

The error to return if the key is not present.

Returns

Result<TValue>

A result containing the value associated with key in the dictionary, or an error if the key is not present.

Type Parameters

TKey

The type of keys in the dictionary.

TValue

The type of values in the dictionary.

Unnest<T>(Result<Result<T>>)

Takes a result containing another result and un-nests the inner result.

[Pure]
public static Result<T> Unnest<T>(this Result<Result<T>> result)

Parameters

result Result<Result<T>>

The result to un-nest.

Returns

Result<T>

Extensions for or relating to .

Type Parameters

T

The type of the ok value in the result.

Remarks

This operation is the same as applying Then<TNew>(Func<T, Result<TNew>>) with the identity function, eg. r.Then(x => x).