Class MaybeExtensions

Namespace

Vonage.Common.Monads

Assembly

Vonage.dll

Exposes a set of extensions for Maybe, including async operations on Task of Maybe.

public static class MaybeExtensions

Inheritance

object

MaybeExtensions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Methods

BindAsync<TSource, TDestination>(Task<Maybe<TSource>>, Func<TSource, Task<Maybe<TDestination>>>)

Monadic bind operation with an asynchronous bind function.

public static Task<Maybe<TDestination>> BindAsync<TSource, TDestination>(this Task<Maybe<TSource>> task, Func<TSource, Task<Maybe<TDestination>>> bind)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

bind Func<TSource, Task<Maybe<TDestination>>>

Asynchronous bind operation.

Returns

Task<Maybe<TDestination>>

Bound functor.

Type Parameters

TSource

Source type.

TDestination

Return type.

Examples

Task<Maybe<int>> asyncUserId = GetUserIdAsync();
Maybe<User> user = await asyncUserId.BindAsync(id => FetchUserAsync(id));

Bind<TSource, TDestination>(Task<Maybe<TSource>>, Func<TSource, Maybe<TDestination>>)

Monadic bind operation on an asynchronous Maybe.

public static Task<Maybe<TDestination>> Bind<TSource, TDestination>(this Task<Maybe<TSource>> task, Func<TSource, Maybe<TDestination>> bind)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

bind Func<TSource, Maybe<TDestination>>

Bind operation.

Returns

Task<Maybe<TDestination>>

Bound functor.

Type Parameters

TSource

Source type.

TDestination

Return type.

Examples

Task<Maybe<string>> asyncValue = GetValueAsync();
Maybe<int> result = await asyncValue.Bind(value => ParseInt(value));

DoWhenNone<TSource>(Task<Maybe<TSource>>, Action)

Executes an operation if the asynchronous Maybe is in None state.

public static Task<Maybe<TSource>> DoWhenNone<TSource>(this Task<Maybe<TSource>> task, Action noneOperation)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

noneOperation Action

None operation.

Returns

Task<Maybe<TSource>>

The original Maybe.

Type Parameters

TSource

Source type.

Examples

Task<Maybe<string>> asyncName = GetNameAsync();
await asyncName.DoWhenNone(() => Console.WriteLine("No value found"));

DoWhenSome<TSource>(Task<Maybe<TSource>>, Action<TSource>)

Executes an operation if the asynchronous Maybe is in Some state.

public static Task<Maybe<TSource>> DoWhenSome<TSource>(this Task<Maybe<TSource>> task, Action<TSource> someOperation)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

someOperation Action<TSource>

Some operation.

Returns

Task<Maybe<TSource>>

The original Maybe.

Type Parameters

TSource

Source type.

Examples

Task<Maybe<string>> asyncName = GetNameAsync();
await asyncName.DoWhenSome(name => Console.WriteLine($"Hello, {name}!"));

Do<TSource>(Task<Maybe<TSource>>, Action<TSource>, Action)

Executes operations depending on the current state of an asynchronous Maybe.

public static Task<Maybe<TSource>> Do<TSource>(this Task<Maybe<TSource>> task, Action<TSource> someOperation, Action noneOperation)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

someOperation Action<TSource>

Some operation.

noneOperation Action

None operation.

Returns

Task<Maybe<TSource>>

The original Maybe.

Type Parameters

TSource

Source type.

Examples

Task<Maybe<string>> asyncName = GetNameAsync();
await asyncName.Do(
    someOperation: name => Console.WriteLine($"Found: {name}"),
    noneOperation: () => Console.WriteLine("Not found")
);

FromNonEmptyString(string)

Creates a Maybe from a string value.

public static Maybe<string> FromNonEmptyString(string value)

Parameters

value string

The string value.

Returns

Maybe<string>

A None state if the value is null or whitespace. A Some state otherwise.

Examples

Maybe<string> name = MaybeExtensions.FromNonEmptyString("Alice"); // Some("Alice")
Maybe<string> empty = MaybeExtensions.FromNonEmptyString(""); // None
Maybe<string> whitespace = MaybeExtensions.FromNonEmptyString("   "); // None

IfNone<TSource>(Task<Maybe<TSource>>, TSource)

Returns the specified value if the asynchronous Maybe is in the None state, the Some value otherwise.

public static Task<TSource> IfNone<TSource>(this Task<Maybe<TSource>> task, TSource noneValue)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

noneValue TSource

The value to return if in None state.

Returns

Task<TSource>

A value.

Type Parameters

TSource

Source type.

Examples

Task<Maybe<int>> asyncCount = GetCountAsync();
int count = await asyncCount.IfNone(0); // Returns 0 if None

MapAsync<TSource, TDestination>(Task<Maybe<TSource>>, Func<TSource, Task<TDestination>>)

Projects from one value to another using an asynchronous projection function.

public static Task<Maybe<TDestination>> MapAsync<TSource, TDestination>(this Task<Maybe<TSource>> task, Func<TSource, Task<TDestination>> map)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

map Func<TSource, Task<TDestination>>

Asynchronous projection function.

Returns

Task<Maybe<TDestination>>

Mapped functor.

Type Parameters

TSource

Source type.

TDestination

Resulting functor value type.

Examples

Task<Maybe<int>> asyncId = GetIdAsync();
Maybe<string> name = await asyncId.MapAsync(id => FetchNameAsync(id));

Map<TSource, TDestination>(Task<Maybe<TSource>>, Func<TSource, TDestination>)

Projects from one value to another on an asynchronous Maybe.

public static Task<Maybe<TDestination>> Map<TSource, TDestination>(this Task<Maybe<TSource>> task, Func<TSource, TDestination> map)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

map Func<TSource, TDestination>

Projection function.

Returns

Task<Maybe<TDestination>>

Mapped functor.

Type Parameters

TSource

Source type.

TDestination

Resulting functor value type.

Examples

Task<Maybe<string>> asyncName = GetNameAsync();
Maybe<int> length = await asyncName.Map(name => name.Length);

Match<TSource, TDestination>(Task<Maybe<TSource>>, Func<TSource, TDestination>, Func<TDestination>)

Match the two states of an asynchronous Maybe and return a non-null TDestination.

public static Task<TDestination> Match<TSource, TDestination>(this Task<Maybe<TSource>> task, Func<TSource, TDestination> some, Func<TDestination> none)

Parameters

task Task<Maybe<TSource>>

Asynchronous Maybe.

some Func<TSource, TDestination>

Some match operation.

none Func<TDestination>

None match operation.

Returns

Task<TDestination>

A non-null TDestination.

Type Parameters

TSource

Source type.

TDestination

Return type.

Examples

Task<Maybe<string>> asyncName = GetNameAsync();
string greeting = await asyncName.Match(
    some: name => $"Hello, {name}!",
    none: () => "Hello, stranger!"
);