Class Prelude

Namespace

Rascal

Assembly

Rascal.dll

A class containing various utility methods, a 'prelude' to the rest of the library.

public static class Prelude

Inheritance

object

Prelude

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

This class is meant to be imported statically, eg. using static Rascal.Prelude;. Recommended to be imported globally via a global using statement.

Methods

Err<T>(Error)

Creates a result containing an error.

[Pure]
public static Result<T> Err<T>(Error error)

Parameters

error Error

The error to create the result from.

Returns

Result<T>

A class containing various utility methods, a 'prelude' to the rest of the library.

Type Parameters

T

The type of an ok value in the result.

Iterate<T>(Result<T>, Func<T, Result<T>>)

Applies a transform function onto a value until the function returns an error.

[Pure]
public static IEnumerable<T> Iterate<T>(Result<T> start, Func<T, Result<T>> transform)

Parameters

start Result<T>

The starting value.

transform Func<T, Result<T>>

A function which transforms a value into either a new value or an error.

Returns

IEnumerable<T>

A sequence of successful values produced by repeatedly applying transform onto the previous value until an error is returned. Includes start if it has a value, otherwise the sequence will be empty.

Type Parameters

T

The type of the value transform.

Iterate<T>(T, Func<T, Result<T>>)

Applies a transform function onto a value until the function returns an error.

[Pure]
public static IEnumerable<T> Iterate<T>(T start, Func<T, Result<T>> transform)

Parameters

start T

The starting value.

transform Func<T, Result<T>>

A function which transforms a value into either a new value or an error.

Returns

IEnumerable<T>

A sequence of successful values produced by repeatedly applying transform onto the previous value starting with start until an error is returned. start will always be the first element.

Type Parameters

T

The type of the value transform.

Ok<T>(T)

Creates a result containing an ok value.

[Pure]
public static Result<T> Ok<T>(T value)

Parameters

value T

The ok value to create the result from.

Returns

Result<T>

A class containing various utility methods, a 'prelude' to the rest of the library.

Type Parameters

T

The type of the ok value.

TryAsync<T>(Func<Task<T>>)

Tries to execute an asynchronous function and return the result. If the function throws an exception, the exception will be returned wrapped in an ExceptionError.

[Pure]
public static Task<Result<T>> TryAsync<T>(Func<Task<T>> function)

Parameters

function Func<Task<T>>

The function to try execute.

Returns

Task<Result<T>>

A result containing the return value of the function or an ExceptionError containing the exception thrown by the function.

Type Parameters

T

The type the function returns.

Try<T>(Func<T>)

Tries to execute a function and return the result. If the function throws an exception, the exception will be returned wrapped in an ExceptionError.

[Pure]
public static Result<T> Try<T>(Func<T> function)

Parameters

function Func<T>

The function to try execute.

Returns

Result<T>

A result containing the return value of the function or an ExceptionError containing the exception thrown by the function.

Type Parameters

T

The type the function returns.