feat: add inital in memory dispatcher

Add a simple in memory dispatcher for scalar requests and stream request.

src/request.result/Geekeey.Request.Result.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <IsPackable>true</IsPackable>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(Configuration)' == 'Debug'">
+    <InternalsVisibleTo Include="Geekeey.Request.Result.Tests" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <PackageReadmeFile>package-readme.md</PackageReadmeFile>
+    <PackageIcon>package-icon.png</PackageIcon>
+    <PackageProjectUrl>https://code.geekeey.de/geekeey/request/src/branch/main/src/request.result</PackageProjectUrl>
+    <PackageLicenseExpression>EUPL-1.2</PackageLicenseExpression>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include=".\package-icon.png" Pack="true" PackagePath="\" Visible="false" />
+    <None Include=".\package-readme.md" Pack="true" PackagePath="\" Visible="false" />
+    <None Include="..\..\LICENSE.md" Pack="true" PackagePath="\" Visible="false" />
+  </ItemGroup>
+
+</Project>

src/request.result/Prelude.cs

@@ -0,0 +1,101 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// A class containing various utility methods, a 'prelude' to the rest of the library.
+/// </summary>
+/// <remarks>
+/// This class is meant to be imported statically, e.g. <c>using static Geekeey.Extensions.Result.Prelude;</c>.
+/// Recommended to be imported globally via a global using statement.
+/// </remarks>
+public static class Prelude
+{
+	/// <summary>
+	/// Creates a result containing a success value.
+	/// </summary>
+	/// <typeparam name="T">The type of the success value.</typeparam>
+	/// <param name="value">The success value to create the result from.</param>
+	[Pure]
+	public static Result<T> Success<T>(T value)
+	{
+		return new Result<T>(value);
+	}
+
+	/// <summary>
+	/// Creates a result containing a failure value.
+	/// </summary>
+	/// <typeparam name="T">The type of success value in the result.</typeparam>
+	/// <param name="error">The failure value to create the result from.</param>
+	[Pure]
+	public static Result<T> Failure<T>(Error error)
+	{
+		return new Result<T>(error);
+	}
+
+	/// <summary>
+	/// Tries to execute a function and return the result. If the function throws an exception, the exception will be
+	/// returned wrapped in an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <typeparam name="T">The type the function returns.</typeparam>
+	/// <param name="function">The function to try to execute.</param>
+	/// <returns>A result containing the return value of the function or an <see cref="ExceptionError"/> containing the
+	/// exception thrown by the function.</returns>
+	[Pure]
+	public static Result<T> Try<T>(Func<T> function)
+	{
+		try
+		{
+			return new Result<T>(function());
+		}
+		catch (Exception exception)
+		{
+			return new Result<T>(new ExceptionError(exception));
+		}
+	}
+
+	/// <summary>
+	/// Tries to execute an asynchronous function and return the result. If the function throws an exception, the
+	/// exception will be returned wrapped in an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <typeparam name="T">The type the function returns.</typeparam>
+	/// <param name="function">The function to try to execute.</param>
+	/// <returns>A result containing the return value of the function or an <see cref="ExceptionError"/> containing the
+	/// exception thrown by the function.</returns>
+	[Pure]
+	public static async ValueTask<Result<T>> TryAsync<T>(Func<ValueTask<T>> function)
+	{
+		try
+		{
+			return new Result<T>(await function());
+		}
+		catch (Exception exception)
+		{
+			return new Result<T>(new ExceptionError(exception));
+		}
+	}
+
+	/// <summary>
+	/// Tries to execute an asynchronous function and return the result. If the function throws an exception, the
+	/// exception will be returned wrapped in an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <typeparam name="T">The type the function returns.</typeparam>
+	/// <param name="function">The function to try to execute.</param>
+	/// <returns>A result containing the return value of the function or an <see cref="ExceptionError"/> containing the
+	/// exception thrown by the function.</returns>
+	[Pure]
+	public static async Task<Result<T>> TryAsync<T>(Func<Task<T>> function)
+	{
+		try
+		{
+			return new Result<T>(await function());
+		}
+		catch (Exception exception)
+		{
+			return new Result<T>(new ExceptionError(exception));
+		}
+	}
+}

src/request.result/Result.Conversion.cs

@@ -0,0 +1,51 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Implicitly constructs a result from a success value.
+	/// </summary>
+	/// <param name="value">The value to construct the result from.</param>
+	[Pure]
+	public static implicit operator Result<T>(T value)
+	{
+		return new Result<T>(value);
+	}
+
+	/// <summary>
+	/// Implicitly constructs a result from a failure value.
+	/// </summary>
+	/// <param name="error">The error to construct the result from.</param>
+	[Pure]
+	public static implicit operator Result<T>(Error error)
+	{
+		return new Result<T>(error);
+	}
+
+	/// <summary>
+	/// Unwraps the success value of the result. Throws an <see cref="UnwrapException"/> if the result is a failure.
+	/// </summary>
+	/// <remarks>
+	/// This call is <b>unsafe</b> in the sense that it might intentionally throw an exception. Please only use this
+	/// call if the caller knows that this operation is safe, or that an exception is acceptable to be thrown.
+	/// </remarks>
+	/// <returns>The success value of the result.</returns>
+	/// <exception cref="UnwrapException">The result is not a success.</exception>
+	[Pure]
+	public T Unwrap()
+	{
+		return IsSuccess ? Value : throw new UnwrapException();
+	}
+
+	/// <inheritdoc cref="Unwrap"/>
+	[Pure]
+	public static explicit operator T(Result<T> result)
+	{
+		return result.Unwrap();
+	}
+}

src/request.result/Result.Equality.cs

@@ -0,0 +1,163 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Numerics;
+
+namespace Geekeey.Request.Result;
+
+public readonly partial struct Result<T> : IEquatable<Result<T>>, IEquatable<T>
+{
+	/// <summary>
+	/// Checks whether the result is equal to another result. Results are equal if both results are success values and
+	/// the success values are equal, or if both results are failures.
+	/// </summary>
+	/// <param name="other">The result to check for equality with the current result.</param>
+	[Pure]
+	public bool Equals(Result<T> other)
+	{
+		return Equals(this, other, EqualityComparer<T>.Default);
+	}
+
+	/// <summary>
+	/// Checks whether the result is equal to another result. Results are equal if both results are success values and
+	/// the success values are equal, or if both results are failures.
+	/// </summary>
+	/// <param name="other">The result to check for equality with the current result.</param>
+	/// <param name="comparer">The equality comparer to use for comparing values.</param>
+	[Pure]
+	public bool Equals(Result<T> other, IEqualityComparer<T> comparer)
+	{
+		return Equals(this, other, comparer);
+	}
+
+	/// <summary>
+	/// Checks whether the result is a success value and the success value is equal to another value.
+	/// </summary>
+	/// <param name="other">The value to check for equality with the success value of the result.</param>
+	[Pure]
+	public bool Equals(T? other)
+	{
+		return Equals(this, other, EqualityComparer<T>.Default);
+	}
+
+	/// <summary>
+	/// Checks whether the result is a success value and the success value is equal to another value using a specified
+	/// equality comparer.
+	/// </summary>
+	/// <param name="other">The value to check for equality with the success value of the result.</param>
+	/// <param name="comparer">The equality comparer to use for comparing values.</param>
+	[Pure]
+	public bool Equals(T? other, IEqualityComparer<T> comparer)
+	{
+		return Equals(this, other, comparer);
+	}
+
+	/// <inheritdoc/>
+	[Pure]
+	public override bool Equals(object? obj)
+	{
+		return (obj is T x && Equals(x)) || (obj is Result<T> r && Equals(r));
+	}
+
+	/// <inheritdoc/>
+	[Pure]
+	public override int GetHashCode()
+	{
+		return GetHashCode(this, EqualityComparer<T>.Default);
+	}
+
+	internal static bool Equals(Result<T> a, Result<T> b, IEqualityComparer<T> comparer)
+	{
+		if (!a.IsSuccess || !b.IsSuccess)
+		{
+			return !a.IsSuccess && !b.IsSuccess;
+		}
+
+		if (a.Value is null || b.Value is null)
+		{
+			return a.Value is null && b.Value is null;
+		}
+
+		return comparer.Equals(a.Value, b.Value);
+	}
+
+	internal static bool Equals(Result<T> a, T? b, IEqualityComparer<T> comparer)
+	{
+		if (!a.IsSuccess)
+		{
+			return false;
+		}
+
+		if (a.Value is null || b is null)
+		{
+			return a.Value is null && b is null;
+		}
+
+		return comparer.Equals(a.Value, b);
+	}
+
+	internal static int GetHashCode(Result<T> result, IEqualityComparer<T> comparer)
+	{
+		if (result is { IsSuccess: true, Value: not null })
+		{
+			return comparer.GetHashCode(result.Value);
+		}
+
+		return 0;
+	}
+}
+
+public readonly partial struct Result<T> : IEqualityOperators<Result<T>, Result<T>, bool>, IEqualityOperators<Result<T>, T, bool>
+{
+	/// <summary>
+	/// Checks whether two results are equal. Results are equal if both results are success values and the success
+	/// values are equal, or if both results are failures.
+	/// </summary>
+	/// <param name="a">The first result to compare.</param>
+	/// <param name="b">The second result to compare.</param>
+	[Pure]
+	[ExcludeFromCodeCoverage]
+	public static bool operator ==(Result<T> a, Result<T> b)
+	{
+		return Equals(a, b, EqualityComparer<T>.Default);
+	}
+
+	/// <summary>
+	/// Checks whether two results are not equal. Results are equal if both results are success values and the success
+	/// values are equal, or if both results are failures.
+	/// </summary>
+	/// <param name="a">The first result to compare.</param>
+	/// <param name="b">The second result to compare.</param>
+	[Pure]
+	[ExcludeFromCodeCoverage]
+	public static bool operator !=(Result<T> a, Result<T> b)
+	{
+		return !Equals(a, b, EqualityComparer<T>.Default);
+	}
+
+	/// <summary>
+	/// Checks whether a result is a success value and the success value is equal to another value.
+	/// </summary>
+	/// <param name="a">The result to compare.</param>
+	/// <param name="b">The value to check for equality with the success value in the result.</param>
+	[Pure]
+	[ExcludeFromCodeCoverage]
+	public static bool operator ==(Result<T> a, T? b)
+	{
+		return Equals(a, b, EqualityComparer<T>.Default);
+	}
+
+	/// <summary>
+	/// Checks whether a result either does not have a value, or the value is not equal to another value.
+	/// </summary>
+	/// <param name="a">The result to compare.</param>
+	/// <param name="b">The value to check for inequality with the success value in the result.</param>
+	[Pure]
+	[ExcludeFromCodeCoverage]
+	public static bool operator !=(Result<T> a, T? b)
+	{
+		return !Equals(a, b, EqualityComparer<T>.Default);
+	}
+}

src/request.result/Result.Matching.cs

@@ -0,0 +1,104 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Matches over the success value or failure value of the result and returns another value. Can be conceptualized
+	/// as an exhaustive <c>switch</c> expression matching all possible values of the type.
+	/// </summary>
+	/// <typeparam name="TResult">The type to return from the match.</typeparam>
+	/// <param name="success">The function to apply to the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to apply to the failure value of the result if the result is a failure.</param>
+	/// <returns>The result of applying either <paramref name="success"/> or <paramref name="failure"/> on the success
+	/// value or failure value of the result.</returns>
+	[Pure]
+	public TResult Match<TResult>(Func<T, TResult> success, Func<Error, TResult> failure)
+	{
+		return IsSuccess ? success(Value!) : failure(Error!);
+	}
+
+	/// <summary>
+	/// Matches over the success value or failure value of the result and invokes an effectful action onto the success
+	/// value or failure value. Can be conceptualized as an exhaustive <c>switch</c> statement matching all possible
+	/// values of the type.
+	/// </summary>
+	/// <param name="success">The function to call with the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to call with the failure value of the result if the result is a failure.</param>
+	public void Switch(Action<T> success, Action<Error> failure)
+	{
+		if (IsSuccess)
+		{
+			success(Value!);
+		}
+		else
+		{
+			failure(Error!);
+		}
+	}
+}
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Asynchronously matches over the success value or failure value of the result and returns another value. Can be
+	/// conceptualized as an exhaustive <c>switch</c> expression matching all possible values of the type.
+	/// </summary>
+	/// <typeparam name="TResult">The type to return from the match.</typeparam>
+	/// <param name="success">The function to apply to the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to apply to the failure value of the result if the result is a failure.</param>
+	/// <returns>A task completing with the result of applying either <paramref name="success"/> or
+	/// <paramref name="failure"/> on the success value or failure value of the result.</returns>
+	[Pure]
+	public async Task<TResult> MatchAsync<TResult>(Func<T, Task<TResult>> success, Func<Error, Task<TResult>> failure)
+	{
+		return IsSuccess ? await success(Value!) : await failure(Error!);
+	}
+
+	/// <summary>
+	/// Asynchronously matches over the success value or failure value of the result and invokes an effectful action
+	/// onto the success value or failure value. Can be conceptualized as an exhaustive <c>switch</c> statement matching
+	/// all possible values of
+	/// the type.
+	/// </summary>
+	/// <param name="success">The function to call with the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to call with the failure value of the result if the result is a failure.</param>
+	public Task SwitchAsync(Func<T, Task> success, Func<Error, Task> failure)
+	{
+		return IsSuccess ? success(Value!) : failure(Error!);
+	}
+}
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Asynchronously matches over the success value or failure value of the result and returns another value. Can be
+	/// conceptualized as an exhaustive <c>switch</c> expression matching all possible values of the type.
+	/// </summary>
+	/// <typeparam name="TResult">The type to return from the match.</typeparam>
+	/// <param name="success">The function to apply to the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to apply to the failure value of the result if the result is a failure.</param>
+	/// <returns>A task completing with the result of applying either <paramref name="success"/> or
+	/// <paramref name="failure"/> on the success value or failure value of the result.</returns>
+	[Pure]
+	public ValueTask<TResult> MatchAsync<TResult>(Func<T, ValueTask<TResult>> success, Func<Error, ValueTask<TResult>> failure)
+	{
+		return IsSuccess ? success(Value!) : failure(Error!);
+	}
+
+	/// <summary>
+	/// Asynchronously matches over the success value or failure value of the result and invokes an effectful action
+	/// onto the success value or the failure value. Can be conceptualized as an exhaustive <c>switch</c> statement
+	/// matching all possible values of the type.
+	/// </summary>
+	/// <param name="success">The function to call with the success value of the result if the result is a success.</param>
+	/// <param name="failure">The function to call with the failure value of the result if the result is a failure.</param>
+	public ValueTask SwitchAsync(Func<T, ValueTask> success, Func<Error, ValueTask> failure)
+	{
+		return IsSuccess ? success(Value!) : failure(Error!);
+	}
+}

src/request.result/Result.Transform.cs

@@ -0,0 +1,366 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Maps the success value of the result using a mapping function, or does nothing if the result is a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A new result containing either the mapped success value or the failure value of the original
+	/// result.</returns>
+	[Pure]
+	public Result<TNew> Map<TNew>(Func<T, TNew> func)
+	{
+		return IsSuccess ? new Result<TNew>(func(Value!)) : new Result<TNew>(Error!);
+	}
+
+	/// <summary>
+	/// Tries to map the success value of the result using a mapping function, or does nothing if the result is a
+	/// failure. If the mapping function throws an exception, the exception will be returned wrapped in an
+	/// <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A new result containing either the mapped value, the exception thrown by <paramref name="func"/>
+	/// wrapped in an <see cref="ExceptionError"/>, or the failure value of the original result.</returns>
+	[Pure]
+	public Result<TNew> TryMap<TNew>(Func<T, TNew> func)
+	{
+		try
+		{
+			return Map(func);
+		}
+		catch (Exception exception)
+		{
+			return new Result<TNew>(new ExceptionError(exception));
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result to a new result using a mapping function, or does nothing if the result is
+	/// a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A result which is either the mapped result or a new result containing the failure value of the original
+	/// result.</returns>
+	[Pure]
+	public Result<TNew> Then<TNew>(Func<T, Result<TNew>> func)
+	{
+		return IsSuccess ? func(Value!) : new Result<TNew>(Error!);
+	}
+
+	/// <summary>
+	/// Tries to map the success value of the result to a new result using a mapping function, or does nothing if the result
+	/// is a failure. If the mapping function throws an exception, the exception will be returned wrapped in an
+	/// <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A result which is either the mapped result, the exception thrown by <paramref name="func"/> wrapped in
+	/// an <see cref="ExceptionError"/>, or a new result containing the failure value of the original result.</returns>
+	[Pure]
+	public Result<TNew> ThenTry<TNew>(Func<T, Result<TNew>> func)
+	{
+		try
+		{
+			return Then(func);
+		}
+		catch (Exception exception)
+		{
+			return new Result<TNew>(new ExceptionError(exception));
+		}
+	}
+}
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Maps the success value of the result using an asynchronous mapping function, or does nothing if the result is
+	/// a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="Task{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result and constructing a new result containing the mapped value, or completes
+	/// synchronously by returning a new result containing the failure value of the original result.</returns>
+	[Pure]
+	public Task<Result<TNew>> MapAsync<TNew>(Func<T, Task<TNew>> func)
+	{
+		if (!IsSuccess)
+		{
+			return Task.FromResult(new Result<TNew>(Error!));
+		}
+
+		var task = func(Value!);
+		return CreateResult(task);
+
+		static async Task<Result<TNew>> CreateResult(Task<TNew> task)
+		{
+			var value = await task;
+			return new Result<TNew>(value);
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result using an asynchronous mapping function, or does nothing if the result is a
+	/// failure. If the mapping function throws an exception, the exception will be returned wrapped in an
+	/// <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="Task{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result and constructing a new result containing the mapped value, returning any exception
+	/// thrown by <paramref name="func"/> wrapped in an <see cref="ExceptionError"/> or completes synchronously by
+	/// returning a new result containing the failure value of the original result.</returns>
+	[Pure]
+	public Task<Result<TNew>> TryMapAsync<TNew>(Func<T, Task<TNew>> func)
+	{
+		if (!IsSuccess)
+		{
+			return Task.FromResult(new Result<TNew>(Error!));
+		}
+
+		try
+		{
+			var task = func(Value!);
+			return CreateResult(task);
+		}
+		catch (Exception exception)
+		{
+			return Task.FromResult(new Result<TNew>(new ExceptionError(exception)));
+		}
+
+		static async Task<Result<TNew>> CreateResult(Task<TNew> task)
+		{
+			try
+			{
+				var value = await task;
+				return new Result<TNew>(value);
+			}
+			catch (Exception exception)
+			{
+				return new Result<TNew>(new ExceptionError(exception));
+			}
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result to a new result using an asynchronous mapping function, or does nothing if
+	/// the result is a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="Task{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result, or completes synchronously by returning a new result containing the failure
+	/// value of the original result.</returns>
+	[Pure]
+	public Task<Result<TNew>> ThenAsync<TNew>(Func<T, Task<Result<TNew>>> func)
+	{
+		if (!IsSuccess)
+		{
+			return Task.FromResult(new Result<TNew>(Error!));
+		}
+
+		var task = func(Value!);
+		return CreateResult(task);
+
+		static async Task<Result<TNew>> CreateResult(Task<Result<TNew>> task)
+		{
+			var result = await task;
+			return result;
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result to a new result using an asynchronous mapping function, or does nothing if
+	/// the result is a failure. If the mapping function throws an exception, the exception will be returned wrapped in
+	/// an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="Task{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result, returning any exception thrown by <paramref name="func"/> wrapped in an
+	/// <see cref="ExceptionError"/>, or completes synchronously by returning a new result containing the failure value
+	/// of the original result.</returns>
+	[Pure]
+	public Task<Result<TNew>> ThenTryAsync<TNew>(Func<T, Task<Result<TNew>>> func)
+	{
+		if (!IsSuccess)
+		{
+			return Task.FromResult(new Result<TNew>(Error!));
+		}
+
+		try
+		{
+			var task = func(Value!);
+			return CreateResult(task);
+		}
+		catch (Exception exception)
+		{
+			return Task.FromResult(new Result<TNew>(new ExceptionError(exception)));
+		}
+
+		static async Task<Result<TNew>> CreateResult(Task<Result<TNew>> task)
+		{
+			try
+			{
+				var value = await task;
+				return value;
+			}
+			catch (Exception exception)
+			{
+				return new Result<TNew>(new ExceptionError(exception));
+			}
+		}
+	}
+}
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Maps the success value of the result using an asynchronous mapping function, or does nothing if the result is
+	/// a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="ValueTask{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result and constructing a new result containing the mapped value, or completes
+	/// synchronously by returning a new result containing the failure value of the original result.</returns>
+	[Pure]
+	public ValueTask<Result<TNew>> MapAsync<TNew>(Func<T, ValueTask<TNew>> func)
+	{
+		if (!IsSuccess)
+		{
+			return ValueTask.FromResult(new Result<TNew>(Error!));
+		}
+
+		var task = func(Value!);
+		return CreateResult(task);
+
+		static async ValueTask<Result<TNew>> CreateResult(ValueTask<TNew> task)
+		{
+			var value = await task;
+			return new Result<TNew>(value);
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result using an asynchronous mapping function, or does nothing if the result is a
+	/// failure. If the mapping function throws an exception, the exception will be returned wrapped in an
+	/// <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="ValueTask{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result and constructing a new result containing the mapped value, returning any exception
+	/// thrown by <paramref name="func"/> wrapped in an <see cref="ExceptionError"/> or completes synchronously by
+	/// returning a new result containing the failure value of the original result.</returns>
+	[Pure]
+	public ValueTask<Result<TNew>> TryMapAsync<TNew>(Func<T, ValueTask<TNew>> func)
+	{
+		if (!IsSuccess)
+		{
+			return ValueTask.FromResult(new Result<TNew>(Error!));
+		}
+
+		try
+		{
+			var task = func(Value!);
+			return CreateResult(task);
+		}
+		catch (Exception exception)
+		{
+			return ValueTask.FromResult(new Result<TNew>(new ExceptionError(exception)));
+		}
+
+		static async ValueTask<Result<TNew>> CreateResult(ValueTask<TNew> task)
+		{
+			try
+			{
+				var value = await task;
+				return new Result<TNew>(value);
+			}
+			catch (Exception exception)
+			{
+				return new Result<TNew>(new ExceptionError(exception));
+			}
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result to a new result using an asynchronous mapping function, or does nothing if
+	/// the result is a failure.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="ValueTask{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result, or completes synchronously by returning a new result containing the failure
+	/// value of the original result.</returns>
+	[Pure]
+	public ValueTask<Result<TNew>> ThenAsync<TNew>(Func<T, ValueTask<Result<TNew>>> func)
+	{
+		if (!IsSuccess)
+		{
+			return ValueTask.FromResult(new Result<TNew>(Error!));
+		}
+
+		var task = func(Value!);
+		return CreateResult(task);
+
+		static async ValueTask<Result<TNew>> CreateResult(ValueTask<Result<TNew>> task)
+		{
+			var result = await task;
+			return result;
+		}
+	}
+
+	/// <summary>
+	/// Maps the success value of the result to a new result using an asynchronous mapping function, or does nothing if
+	/// the result is a failure. If the mapping function throws an exception, the exception will be returned wrapped in
+	/// an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="func">The function used to map the success value to a new result.</param>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A <see cref="ValueTask{T}"/> which either completes asynchronously by invoking the mapping function on
+	/// the success value of the result, returning any exception thrown by <paramref name="func"/> wrapped in an
+	/// <see cref="ExceptionError"/>, or completes synchronously by returning a new result containing the failure value
+	/// of the original result.</returns>
+	[Pure]
+	public ValueTask<Result<TNew>> ThenTryAsync<TNew>(Func<T, ValueTask<Result<TNew>>> func)
+	{
+		if (!IsSuccess)
+		{
+			return ValueTask.FromResult(new Result<TNew>(Error!));
+		}
+
+		try
+		{
+			var task = func(Value!);
+			return CreateResult(task);
+		}
+		catch (Exception exception)
+		{
+			return ValueTask.FromResult(new Result<TNew>(new ExceptionError(exception)));
+		}
+
+		static async ValueTask<Result<TNew>> CreateResult(ValueTask<Result<TNew>> task)
+		{
+			try
+			{
+				var value = await task;
+				return value;
+			}
+			catch (Exception exception)
+			{
+				return new Result<TNew>(new ExceptionError(exception));
+			}
+		}
+	}
+}

src/request.result/Result.Unbox.cs

@@ -0,0 +1,66 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Tries to get the success value from the result.
+	/// </summary>
+	/// <param name="value">The success value of the result.</param>
+	/// <returns>Whether the result has success value.</returns>
+	[Pure]
+	public bool TryGetValue([MaybeNullWhen(false)] out T value)
+	{
+		value = Value;
+
+		return IsSuccess;
+	}
+
+	/// <summary>
+	/// Tries to get the success value from the result.
+	/// </summary>
+	/// <param name="value">The success value of the result.</param>
+	/// <param name="error">The failure value of the result.</param>
+	/// <returns>Whether the result has a success value.</returns>
+	[Pure]
+	public bool TryGetValue([MaybeNullWhen(false)] out T value, [MaybeNullWhen(true)] out Error error)
+	{
+		value = Value;
+		error = !IsSuccess ? Error : null;
+
+		return IsSuccess;
+	}
+
+	/// <summary>
+	/// Tries to get the failure value from the result.
+	/// </summary>
+	/// <param name="error">The failure value of the result.</param>
+	/// <returns>Whether the result has a failure value.</returns>
+	[Pure]
+	public bool TryGetValue([MaybeNullWhen(false)] out Error error)
+	{
+		error = !IsSuccess ? Error : null;
+
+		return !IsSuccess;
+	}
+
+	/// <summary>
+	/// Tries to get the failure value from the result.
+	/// </summary>
+	/// <param name="error">The failure value of the result.</param>
+	/// <param name="value">The success value of the result.</param>
+	/// <returns>Whether the result a failure value.</returns>
+	[Pure]
+	public bool TryGetValue([MaybeNullWhen(false)] out Error error, [MaybeNullWhen(true)] out T value)
+	{
+		error = !IsSuccess ? Error : null;
+		value = Value;
+
+		return !IsSuccess;
+	}
+}

src/request.result/Result.cs

@@ -0,0 +1,76 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// A type which contains either a success value or a failure value, which is represented by an <see cref="Error"/>.
+/// </summary>
+/// <typeparam name="T">The type of the success value.</typeparam>
+[DebuggerTypeProxy(typeof(Result<>.ResultDebugProxy))]
+public readonly partial struct Result<T>
+{
+	/// <summary>
+	/// Creates a new result with a success value.
+	/// </summary>
+	/// <param name="value">The success value.</param>
+	public Result(T value)
+	{
+		IsSuccess = true;
+		Value = value;
+		Error = default;
+	}
+
+	/// <summary>
+	/// Creates a new result with a failure value.
+	/// </summary>
+	/// <param name="error">The error of the result.</param>
+	public Result(Error error)
+	{
+		IsSuccess = false;
+		Value = default;
+		Error = error;
+	}
+
+	internal T? Value { get; }
+
+	internal Error? Error => IsSuccess ? null : (field ?? Error.DefaultValueError);
+
+	/// <summary>
+	/// Whether the result is a success.
+	/// </summary>
+	/// <remarks>
+	/// This is always the inverse of <see cref="IsFailure"/> but is more specific about intent.
+	/// </remarks>
+	[MemberNotNullWhen(true, nameof(Value))]
+	public bool IsSuccess { get; }
+
+	/// <summary>
+	/// Whether the result is a failure.
+	/// </summary>
+	/// <remarks>
+	/// This is always the inverse of <see cref="IsSuccess"/> but is more specific about intent.
+	/// </remarks>
+	[MemberNotNullWhen(true, nameof(Error))]
+	public bool IsFailure => !IsSuccess;
+
+	/// <summary>
+	/// Gets a string representation of the result.
+	/// </summary>
+	[Pure]
+	public override string ToString()
+	{
+		return IsSuccess ? $"Success {{ {Value} }}" : $"Failure {{ {Error} }}";
+	}
+
+	private sealed class ResultDebugProxy(Result<T> result)
+	{
+		public bool IsSuccess => result.IsSuccess;
+
+		public object? Value => result.IsSuccess ? result.Value : result.Error;
+	}
+}

src/request.result/_errors/AggregateError.cs

@@ -0,0 +1,27 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// An error which is a combination of other errors.
+/// </summary>
+public sealed class AggregateError : Error
+{
+	/// <summary>
+	/// An error which is a combination of other errors.
+	/// </summary>
+	/// <param name="errors">The errors the error consists of.</param>
+	public AggregateError(IEnumerable<Error> errors)
+	{
+		Errors = [.. errors];
+	}
+
+	/// <summary>
+	/// The errors the error consists of.
+	/// </summary>
+	public IReadOnlyCollection<Error> Errors { get; }
+
+	/// <inheritdoc/>
+	public override string Message => string.Join(Environment.NewLine, Errors.Select(error => error.Message));
+}

src/request.result/_errors/Error.cs

@@ -0,0 +1,54 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// An error containing a simple message. Makes up the other half of a <see cref="Result{T}"/> which might be an error.
+/// </summary>
+/// <remarks>
+/// An error is conceptually very similar to an exception but without the ability to be thrown, meant to be a more
+/// lightweight type meant to be wrapped in a <see cref="Result{T}"/>.
+/// An error fundamentally only contains a single string message, however other more concrete types such as
+/// <see cref="ExceptionError"/> or <see cref="AggregateError"/> may define other properties.
+/// Errors are meant to be small, specific, and descriptive, such that they are easy to match over and provide specific
+/// handling for specific kinds of errors.
+/// </remarks>
+public abstract class Error
+{
+	/// <summary>
+	/// A statically accessible default "Result has no value." error.
+	/// </summary>
+	internal static Error DefaultValueError { get; } = new StringError("The result has no value.");
+
+	/// <summary>
+	/// The message used to display the error.
+	/// </summary>
+	public abstract string Message { get; }
+
+	/// <summary>
+	/// Gets a string representation of the error. Returns <see cref="Message"/> by default.
+	/// </summary>
+	public override string ToString()
+	{
+		return Message;
+	}
+
+	/// <summary>
+	/// Implicitly converts a string into a <see cref="StringError"/>.
+	/// </summary>
+	/// <param name="message">The message of the error.</param>
+	public static implicit operator Error(string message)
+	{
+		return new StringError(message);
+	}
+
+	/// <summary>
+	/// Implicitly converts an exception into an <see cref="ExceptionError"/>.
+	/// </summary>
+	/// <param name="exception">The exception to convert.</param>
+	public static implicit operator Error(Exception exception)
+	{
+		return new ExceptionError(exception);
+	}
+}

src/request.result/_errors/ExceptionError.cs

@@ -0,0 +1,29 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// An error which is constructed from an exception.
+/// </summary>
+public sealed class ExceptionError : Error
+{
+	/// <summary>
+	/// An error which is constructed from an exception.
+	/// </summary>
+	/// <param name="exception">The exception in the error.</param>
+	public ExceptionError(Exception exception)
+	{
+		Exception = exception;
+	}
+
+	/// <summary>
+	/// The exception in the error.
+	/// </summary>
+	public Exception Exception { get; }
+
+	/// <summary>
+	/// The exception in the error.
+	/// </summary>
+	public override string Message => Exception.Message;
+}

src/request.result/_errors/StringError.cs

@@ -0,0 +1,24 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// An error which displays a simple string.
+/// </summary>
+public sealed class StringError : Error
+{
+	private readonly string _message;
+
+	/// <summary>
+	/// An error which displays a simple string.
+	/// </summary>
+	/// <param name="message">The message to display.</param>
+	public StringError(string message)
+	{
+		_message = message;
+	}
+
+	/// <inheritdoc/>
+	public override string Message => _message;
+}

src/request.result/_exceptions/UnwrapException.cs

@@ -0,0 +1,26 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// The exception is thrown when an <see cref="Result{T}"/> is attempted to be unwrapped contains only a failure value.
+/// </summary>
+public sealed class UnwrapException : Exception
+{
+	/// <summary>
+	/// Creates a new <see cref="UnwrapException"/>.
+	/// </summary>
+	public UnwrapException()
+		: base("Cannot unwrap result because it does not have a value.")
+	{
+	}
+
+	/// <summary>
+	/// Creates a new <see cref="UnwrapException"/>.
+	/// </summary>
+	/// <param name="error">An error message.</param>
+	public UnwrapException(string error) : base(error)
+	{
+	}
+}

src/request.result/_extensions/Extensions.Enumerable.cs

@@ -0,0 +1,90 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// Extensions for or relating to <see cref="Result{T}"/>.
+/// </summary>
+public static partial class Extensions
+{
+	/// <summary>
+	/// Turns a sequence of results into a single result containing the success values in the results only if all the
+	/// results have success values.
+	/// </summary>
+	/// <param name="results">The results to turn into a single sequence.</param>
+	/// <typeparam name="T">The type of the success values in the results.</typeparam>
+	/// <returns>A single result containing a sequence of all the success values from the original sequence of results,
+	/// or the first failure value encountered within the sequence.</returns>
+	/// <remarks>
+	/// This method completely enumerates the input sequence before returning and is not lazy. As a consequence of this,
+	/// the sequence within the returned result is an <see cref="IReadOnlyList{T}"/>.
+	/// </remarks>
+	public static Result<IReadOnlyList<T>> Join<T>(this IEnumerable<Result<T>> results)
+	{
+		_ = results.TryGetNonEnumeratedCount(out var count);
+		var list = new List<T>(count);
+
+		foreach (var result in results)
+		{
+			if (!result.TryGetValue(out T? value, out var error))
+			{
+				return new Result<IReadOnlyList<T>>(error);
+			}
+
+			list.Add(value);
+		}
+
+		return list;
+	}
+
+	/// <inheritdoc cref="Join{T}(IEnumerable{Result{T}})"/>
+	/// <remarks>
+	/// For parallel execution of the async tasks, one should await the <c>Task.WhenAll()</c> of the provided list
+	/// before calling this function
+	/// </remarks>
+	/// <seealso cref="Join{T}(IEnumerable{Result{T}})"/>
+	// ReSharper disable once InconsistentNaming
+	public static async ValueTask<Result<IReadOnlyList<T>>> Join<T>(this IEnumerable<ValueTask<Result<T>>> results)
+	{
+		_ = results.TryGetNonEnumeratedCount(out var count);
+		var list = new List<T>(count);
+
+		foreach (var result in results)
+		{
+			if (!(await result).TryGetValue(out T? value, out var error))
+			{
+				return new Result<IReadOnlyList<T>>(error);
+			}
+
+			list.Add(value);
+		}
+
+		return list;
+	}
+
+	/// <inheritdoc cref="Join{T}(IEnumerable{Result{T}})"/>
+	/// <remarks>
+	/// For parallel execution of the async tasks, one should await the <c>Task.WhenAll()</c> of the provided list
+	/// before calling this function
+	/// </remarks>
+	/// <seealso cref="Join{T}(IEnumerable{Result{T}})"/>
+	// ReSharper disable once InconsistentNaming
+	public static async Task<Result<IReadOnlyList<T>>> Join<T>(this IEnumerable<Task<Result<T>>> results)
+	{
+		_ = results.TryGetNonEnumeratedCount(out var count);
+		var list = new List<T>(count);
+
+		foreach (var result in results)
+		{
+			if (!(await result).TryGetValue(out T? value, out var error))
+			{
+				return new Result<IReadOnlyList<T>>(error);
+			}
+
+			list.Add(value);
+		}
+
+		return list;
+	}
+}

src/request.result/_extensions/Extensions.Task.cs

@@ -0,0 +1,100 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
+
+namespace Geekeey.Request.Result;
+
+/// <summary>
+/// Extensions for or relating to <see cref="Result{T}"/>.
+/// </summary>
+[ExcludeFromCodeCoverage]
+public static partial class Extensions
+{
+	#region Task<Result<T>>
+
+	/// <summary>
+	/// Maps the success value of the result object of the completed task using a mapping function, or does nothing if
+	/// the result object of the completed task is a failure.
+	/// </summary>
+	/// <param name="result">A task object returning a result object when completing.</param>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="T">The type of the object inside the result returned by the task.</typeparam>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A new result containing either the mapped success value or the failure value of the original
+	/// result.</returns>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	// ReSharper disable once InconsistentNaming
+	public static async Task<Result<TNew>> Map<T, TNew>(this Task<Result<T>> result, Func<T, TNew> func)
+	{
+		return (await result).Map(func);
+	}
+
+	/// <inheritdoc cref="Map{T,TNew}(Task{Result{T}},Func{T,TNew})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	public static async Task<Result<TNew>> MapAsync<T, TNew>(this Task<Result<T>> result, Func<T, ValueTask<TNew>> func)
+	{
+		return await (await result).MapAsync(func);
+	}
+
+	/// <summary>
+	/// Maps the success value of the result object of the completed task to a new result using a mapping function, or
+	/// does nothing if the result object of the completed task is a failure.
+	/// </summary>
+	/// <param name="result">A task object returning a result object when completing.</param>
+	/// <param name="func">The function used to map the success value.</param>
+	/// <typeparam name="T">The type of the object inside the result returned by the task.</typeparam>
+	/// <typeparam name="TNew">The type of the new value.</typeparam>
+	/// <returns>A new result containing either the mapped success value or the failure value of the original
+	/// result.</returns>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	// ReSharper disable once InconsistentNaming
+	public static async Task<Result<TNew>> Then<T, TNew>(this Task<Result<T>> result, Func<T, Result<TNew>> func)
+	{
+		return (await result).Then(func);
+	}
+
+	/// <inheritdoc cref="Then{T,TNew}(Task{Result{T}},Func{T,Result{TNew}})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	public static async Task<Result<TNew>> ThenAsync<T, TNew>(this Task<Result<T>> result, Func<T, ValueTask<Result<TNew>>> func)
+	{
+		return await (await result).ThenAsync(func);
+	}
+
+	#endregion
+
+	#region ValueTask<Result<T>>
+
+	/// <inheritdoc cref="Map{T,TNew}(Task{Result{T}},Func{T,TNew})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	// ReSharper disable once InconsistentNaming
+	public static async ValueTask<Result<TNew>> Map<T, TNew>(this ValueTask<Result<T>> result, Func<T, TNew> func)
+	{
+		return (await result).Map(func);
+	}
+
+	/// <inheritdoc cref="Map{T,TNew}(Task{Result{T}},Func{T,TNew})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	public static async ValueTask<Result<TNew>> MapAsync<T, TNew>(this ValueTask<Result<T>> result, Func<T, ValueTask<TNew>> func)
+	{
+		return await (await result).MapAsync(func);
+	}
+
+	/// <inheritdoc cref="Then{T,TNew}(Task{Result{T}},Func{T,Result{TNew}})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	// ReSharper disable once InconsistentNaming
+	public static async ValueTask<Result<TNew>> Then<T, TNew>(this ValueTask<Result<T>> result, Func<T, Result<TNew>> func)
+	{
+		return (await result).Then(func);
+	}
+
+	/// <inheritdoc cref="Then{T,TNew}(Task{Result{T}},Func{T,Result{TNew}})"/>
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+	public static async ValueTask<Result<TNew>> ThenAsync<T, TNew>(this ValueTask<Result<T>> result, Func<T, ValueTask<Result<TNew>>> func)
+	{
+		return await (await result).ThenAsync(func);
+	}
+
+	#endregion
+}

src/request.result/package-readme.md

@@ -0,0 +1,62 @@
+Result is a simple yet powerful [result type](https://doc.rust-lang.org/std/result/) implementation for C#, containing a
+variety of utilities and standard functions for working with result types and integrating them into the rest of C#.
+
+## Features
+
+- **Success and Failure States:** Represent successful outcomes with a value (`Prelude.Success()`) or failures with an
+  error (`Prelude.Failure()`).
+- **Immutability:** `Result<T>` objects are immutable, ensuring thread safety and preventing accidental modification.
+- **Chaining Operations:** Methods like `Map` and `Then` allow for chaining operations on successful results, promoting
+  a functional programming style.
+
+## Getting Started
+
+### Install the NuGet package:
+
+```
+dotnet add package Geekeey.Extensions.Result
+```
+
+You may need to add our NuGet Feed to your `nuget.config` this can be done by adding the following lines
+
+```xml
+<packageSources>
+	<add key="geekeey" value="https://git.geekeey.de/api/packages/geekeey/nuget/index.json" />
+</packageSources>
+```
+
+### Usage
+
+```csharp
+public Result<int> Divide(int dividend, int divisor)
+{
+  if (divisor == 0)
+  {
+    return Prelude.Failure<int>("Division by zero");
+  }
+
+  return Prelude.Success(dividend / divisor);
+}
+
+if (result.IsSuccess)
+{
+  Console.WriteLine("Result: " + result.Value);
+}
+else
+{
+  Console.WriteLine("Error: " + result.Error);
+}
+```
+
+```csharp
+_ = await Prelude.Try(() => File.ReadAllLines("i_do_not_exist.txt"))
+  ThenAsync(static async Task<Result<IReadOnlyList<int>>> (list) =>
+  {
+      using var client = new HttpClient();
+      Task<Result<int>> DoSomeThing(string line)
+          => Prelude.TryAsync(() => client.GetAsync(line))
+              .Map(static async response => int.Parse(await response.Content.ReadAsStringAsync()));
+      var results = await Task.WhenAll(list.Select(DoSomeThing).ToArray());
+      return results.Join();
+  });
+```