Struct Result

Namespace

Trellis

Assembly

Trellis.Results.dll

Static Combine methods for combining multiple independent Result values without chaining.

public readonly struct Result

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Extension Methods

MaybeExtensions.ToResult<TValue>(TValue)

Remarks

Use Result.Combine(r1, r2, r3) when you already have individual Result variables and want to combine them before error checking. This is syntactic sugar over chaining:

// These are equivalent:
Result.Combine(r1, r2, r3)
r1.Combine(r2).Combine(r3)

Methods

Combine<T1, T2>(Result<T1>, Result<T2>)

Combines two independent Result<TValue> instances into a single tuple result.

public static Result<(T1, T2)> Combine<T1, T2>(Result<T1> r1, Result<T2> r2)

Parameters

r1 Result<T1>

First result.

r2 Result<T2>

Second result.

Returns

Result<(T1, T2)>

A success result with a 2-element tuple if both succeed; otherwise a failure with combined errors.

Type Parameters

T1

Type of the first result value.

T2

Type of the second result value.

Examples

var emailResult = EmailAddress.TryCreate(dto.Email);
var nameResult = FirstName.TryCreate(dto.Name);

var result = Result.Combine(emailResult, nameResult)
    .Bind((email, name) => User.Create(email, name));

Failure(Error)

Creates a failed unit result with the specified error.

public static Result<Unit> Failure(Error error)

Parameters

error Error

Error describing the failure.

Returns

Result<Unit>

A failed Result<TValue> of Unit.

FailureIfAsync<TValue>(Func<Task<bool>>, TValue, Error)

Asynchronously determines failure/success using failurePredicate (inverse semantics of SuccessIfAsync<TValue>(Func<Task<bool>>, TValue, Error)).

public static Task<Result<TValue>> FailureIfAsync<TValue>(Func<Task<bool>> failurePredicate, TValue value, Error error)

Parameters

failurePredicate Func<Task<bool>>

Async predicate producing true for failure.

value TValue

Success value if predicate is false.

error Error

Error if predicate is true.

Returns

Task<Result<TValue>>

A task producing a success or failure Result<TValue>.

Type Parameters

TValue

Type of the value.

FailureIf<TValue>(bool, TValue, Error)

Returns failure if isFailure is true; otherwise success with value.

public static Result<TValue> FailureIf<TValue>(bool isFailure, TValue value, Error error)

Parameters

isFailure bool

If true produce a failure result.

value TValue

Success value when not failing.

error Error

Error when failing.

Returns

Result<TValue>

A success or failure Result<TValue>.

Type Parameters

TValue

Type of the value.

FailureIf<TValue>(Func<bool>, in TValue, Error)

Returns failure if the provided predicate returns true; otherwise success with value.

public static Result<TValue> FailureIf<TValue>(Func<bool> failurePredicate, in TValue value, Error error)

Parameters

failurePredicate Func<bool>

Predicate indicating a failure condition.

value TValue

Success value when predicate is false.

error Error

Error when predicate is true.

Returns

Result<TValue>

A success or failure Result<TValue>.

Type Parameters

TValue

Type of the value.

Failure<TValue>(Func<Error>)

Creates a failed result using a deferred error factory.

public static Result<TValue> Failure<TValue>(Func<Error> error)

Parameters

error Func<Error>

Factory function producing an Error.

Returns

Result<TValue>

A failed Result<TValue>.

Type Parameters

TValue

Type of the (missing) success value.

Failure<TValue>(Error)

Creates a failed result with the specified error.

public static Result<TValue> Failure<TValue>(Error error)

Parameters

error Error

Error describing the failure.

Returns

Result<TValue>

A failed Result<TValue>.

Type Parameters

TValue

Type of the (missing) success value.

FromException(Exception, Func<Exception, Error>?)

Converts an exception to a failed unit result using the optional mapper (default Unexpected).

public static Result<Unit> FromException(Exception ex, Func<Exception, Error>? map = null)

Parameters

ex Exception

Exception to convert.

map Func<Exception, Error>

Optional exception-to-error mapper.

Returns

Result<Unit>

A failed unit result.

FromException<T>(Exception, Func<Exception, Error>?)

Converts an exception to a failed result of type T using the optional mapper (default Unexpected).

public static Result<T> FromException<T>(Exception ex, Func<Exception, Error>? map = null)

Parameters

ex Exception

Exception to convert.

map Func<Exception, Error>

Optional exception-to-error mapper.

Returns

Result<T>

A failed result.

Type Parameters

T

Type parameter of the target result.

Success()

Creates a successful unit result (no payload).

public static Result<Unit> Success()

Returns

Result<Unit>

A successful Result<TValue> of Unit.

SuccessIfAsync<TValue>(Func<Task<bool>>, TValue, Error)

Asynchronously determines success/failure using predicate.

public static Task<Result<TValue>> SuccessIfAsync<TValue>(Func<Task<bool>> predicate, TValue value, Error error)

Parameters

predicate Func<Task<bool>>

Async predicate producing true for success.

value TValue

Success value if predicate is true.

error Error

Error if predicate is false.

Returns

Task<Result<TValue>>

A task producing a success or failure Result<TValue>.

Type Parameters

TValue

Type of the success value.

SuccessIf<TValue>(bool, in TValue, Error)

Returns a success or failure result based on isSuccess.

public static Result<TValue> SuccessIf<TValue>(bool isSuccess, in TValue value, Error error)

Parameters

isSuccess bool

If true returns success; otherwise failure.

value TValue

Value for the success case.

error Error

Error for the failure case.

Returns

Result<TValue>

A success or failure Result<TValue>.

Type Parameters

TValue

Type of the success value.

SuccessIf<T1, T2>(bool, in T1, in T2, Error)

Returns a success (tuple) or failure result based on isSuccess.

public static Result<(T1, T2)> SuccessIf<T1, T2>(bool isSuccess, in T1 t1, in T2 t2, Error error)

Parameters

isSuccess bool

If true returns success; otherwise failure.

t1 T1

First value for the success case.

t2 T2

Second value for the success case.

error Error

Error for the failure case.

Returns

Result<(T1, T2)>

A success or failure Result<TValue> with a tuple payload.

Type Parameters

T1

Type of first value.

T2

Type of second value.

Success<TValue>(Func<TValue>)

Creates a successful result by invoking the supplied factory function.

public static Result<TValue> Success<TValue>(Func<TValue> funcOk)

Parameters

funcOk Func<TValue>

Factory function producing the value. Must not be null.

Returns

Result<TValue>

A successful Result<TValue> containing the produced value.

Type Parameters

TValue

Type of the success value.

Exceptions

ArgumentNullException

Thrown if funcOk is null.

Success<TValue>(TValue)

Creates a successful result wrapping the provided value.

public static Result<TValue> Success<TValue>(TValue value)

Parameters

value TValue

Value to wrap in a successful result (may be null for reference types).

Returns

Result<TValue>

A successful Result<TValue> containing value.

Type Parameters

TValue

Type of the success value.

TryAsync<T>(Func<Task<T>>, Func<Exception, Error>?)

Executes the asynchronous function and converts exceptions to a failed result using the optional mapper (default maps to Unexpected).

public static Task<Result<T>> TryAsync<T>(Func<Task<T>> func, Func<Exception, Error>? map = null)

Parameters

func Func<Task<T>>

Asynchronous function to execute.

map Func<Exception, Error>

Optional exception-to-error mapper. If null, a default Unexpected error is used.

Returns

Task<Result<T>>

A task producing either a success or failure result.

Type Parameters

T

Type of the produced value.

Try<T>(Func<T>, Func<Exception, Error>?)

Executes the function and converts exceptions to a failed result using the optional mapper (default maps to Unexpected(string, string, string?)).

public static Result<T> Try<T>(Func<T> func, Func<Exception, Error>? map = null)

Parameters

func Func<T>

Function to execute.

map Func<Exception, Error>

Optional exception-to-error mapper. If null, a default Unexpected error is used.

Returns

Result<T>

A success result with the value or a failure result if an exception was thrown.

Type Parameters

T

Type of the produced value.