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August 6, 2017 03:22
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Putzing with monads
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public class Class1 | |
{ | |
[Fact] | |
public void applesauce() | |
{ | |
Result<int> result = | |
new Success<int>(32) | |
.Bind(i => new Success<int>(i + 1)); | |
result.OnSuccess(Console.WriteLine); | |
Result<int> fail = new Failure<int>("boom!") | |
.Bind(i => new Success<int>(i + 22)); | |
fail.OnSuccess(_ => Console.WriteLine("Shouldn't run.")); | |
fail.OnFailure(Console.WriteLine); | |
} | |
} | |
public static class ResultExtensions | |
{ | |
public static Result<T> Bind<T>(this Result<T> result, Func<T, Result<T>> f) | |
{ | |
switch (result) | |
{ | |
case Failure<T> failure: | |
return new Failure<T>(failure.Message); | |
case Success<T> success: | |
return f(success.Value); | |
default: | |
throw new ArgumentException("Wat?"); | |
} | |
} | |
public static void OnSuccess<T>(this Result<T> result, Action<Success<T>> f) | |
{ | |
if (result is Success<T> success) | |
{ | |
f(success); | |
} | |
} | |
public static void OnFailure<T>(this Result<T> result, Action<Failure<T>> f) | |
{ | |
if (result is Failure<T> failure) | |
{ | |
f(failure); | |
} | |
} | |
} | |
public interface Result<T> | |
{ | |
} | |
public class Success<T> : Result<T> | |
{ | |
public T Value { get; } | |
public Success(T value) | |
{ | |
Value = value; | |
} | |
public override string ToString() | |
{ | |
return $"Success[{Value}]"; | |
} | |
} | |
public class Failure<T> : Result<T> | |
{ | |
public string Message { get; } | |
public Failure(string message) | |
{ | |
Message = message; | |
} | |
public override string ToString() | |
{ | |
return $"Failure[{Message}]"; | |
} | |
} |
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