feat: create request projects for basic CQRS

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;
+	}
+}