add csharp-es sample

2026-04-27 23:09:38 +01:00
parent cb06d80d6a
commit d785852c1c
8 changed files with 509 additions and 0 deletions
@@ -0,0 +1,138 @@
+namespace CsharpEs.Library;
+
+public readonly record struct Result<T, E>
+{
+    private readonly T _value;
+
+    private readonly E _error;
+
+    public bool IsSuccess { get; }
+
+    public bool IsFailure => !IsSuccess;
+
+    public T Value =>
+        IsSuccess
+            ? _value
+            : throw new InvalidOperationException("No value present for failed result.");
+
+    public E Error =>
+        IsFailure
+            ? _error
+            : throw new InvalidOperationException("No error present for successful result.");
+
+    private Result(T value)
+    {
+        _value = value;
+        _error = default!;
+        IsSuccess = true;
+    }
+
+    private Result(E error)
+    {
+        _value = default!;
+        _error = error;
+        IsSuccess = false;
+    }
+
+    public static Result<T, E> Ok(T value) => new(value);
+
+    public static Result<T, E> Fail(E error) => new(error);
+
+    public TResult Match<TResult>(Func<T, TResult> onSuccess, Func<E, TResult> onFailure) =>
+        IsSuccess ? onSuccess(_value) : onFailure(_error);
+
+    public void Switch(Action<T> onSuccess, Action<E> onFailure)
+    {
+        if (IsSuccess)
+            onSuccess(_value);
+        else
+            onFailure(_error);
+    }
+
+    public static Result<T, E> Catch(Func<T> f, Func<Exception, E> exceptionMapper)
+    {
+        try
+        {
+            var result = f();
+            return Result<T, E>.Ok(result);
+        }
+        catch (Exception e)
+        {
+            return Result<T, E>.Fail(exceptionMapper(e));
+        }
+    }
+
+    public static Result<T, E> Catch(Func<Result<T, E>> f, Func<Exception, E> exceptionMapper)
+    {
+        try
+        {
+            return f();
+        }
+        catch (Exception e)
+        {
+            return Result<T, E>.Fail(exceptionMapper(e));
+        }
+    }
+}
+
+public static class ResultExtensions
+{
+    public static Result<TOut, E> Bind<TIn, TOut, E>(
+        this Result<TIn, E> result,
+        Func<TIn, Result<TOut, E>> binder
+    ) => result.IsSuccess ? binder(result.Value) : Result<TOut, E>.Fail(result.Error);
+
+    public static Result<TOut, E> Map<TIn, TOut, E>(
+        this Result<TIn, E> result,
+        Func<TIn, TOut> mapper
+    ) =>
+        result.IsSuccess
+            ? Result<TOut, E>.Ok(mapper(result.Value))
+            : Result<TOut, E>.Fail(result.Error);
+
+    public static Result<T, E> Tap<T, E>(this Result<T, E> result, Action<T> action)
+    {
+        if (result.IsSuccess)
+            action(result.Value);
+
+        return result;
+    }
+
+    public static Result<T, E> TapError<T, E>(this Result<T, E> result, Action<E> action)
+    {
+        if (result.IsFailure)
+            action(result.Error);
+
+        return result;
+    }
+
+    public static Result<T, EOut> MapError<T, EIn, EOut>(
+        this Result<T, EIn> result,
+        Func<EIn, EOut> map
+    ) =>
+        result.IsSuccess
+            ? Result<T, EOut>.Ok(result.Value)
+            : Result<T, EOut>.Fail(map(result.Error));
+
+    public static Result<T, E> Log<T, E>(this Result<T, E> result, string src, string msg) =>
+        Tap(result, Logging.OutputDelegate<T>(src, msg)).TapError(m => Logging.OutputError(src, m));
+
+    public static Result<T, E> Log<T, E>(
+        this Result<T, E> result,
+        string src,
+        Func<T, string> renderText
+    ) =>
+        Tap(result, x => Logging.OutputDelegate<T>(src, renderText(x))(x))
+            .TapError(m => Logging.OutputError(src, m));
+
+    public static Result<TOut, E> Select<TIn, TOut, E>(
+        this Result<TIn, E> result,
+        Func<TIn, TOut> mapper
+    ) => result.Map(mapper);
+
+    public static Result<TOut, E> SelectMany<TIn, TIntermediate, TOut, E>(
+        this Result<TIn, E> result,
+        Func<TIn, Result<TIntermediate, E>> binder,
+        Func<TIn, TIntermediate, TOut> projector
+    ) => result.Bind(x => binder(x).Map(y => projector(x, y)));
+}