Added TransformChannel. Similar to a TransformBlock in Dataflow, but the transformation only occurs on read.

Author: Oren (electricessence)

Open.ChannelExtensions/Extensions.Transform.cs

@@ -8,20 +8,20 @@ namespace Open.ChannelExtensions
 {
 	public static partial class Extensions
 	{
-		class TransformingChannelReader<TIn, TOut> : ChannelReader<TOut>
+		class TransformingChannelReader<T, TResult> : ChannelReader<TResult>
 		{
-			public TransformingChannelReader(ChannelReader<TIn> source, Func<TIn, TOut> transform)
+			public TransformingChannelReader(ChannelReader<T> source, Func<T, TResult> transform)
 			{
 				_source = source ?? throw new ArgumentNullException(nameof(source));
 				_transform = transform ?? throw new ArgumentNullException(nameof(transform));
 				Contract.EndContractBlock();
 			}
 
-			private readonly ChannelReader<TIn> _source;
-			private readonly Func<TIn, TOut> _transform;
+			private readonly ChannelReader<T> _source;
+			private readonly Func<T, TResult> _transform;
 			public override Task Completion => _source.Completion;
 
-			public override bool TryRead(out TOut item)
+			public override bool TryRead(out TResult item)
 			{
 				if (_source.TryRead(out var e))
 				{
@@ -33,7 +33,7 @@ public override bool TryRead(out TOut item)
 				return false;
 			}
 
-			public override async ValueTask<TOut> ReadAsync(CancellationToken cancellationToken = default)
+			public override async ValueTask<TResult> ReadAsync(CancellationToken cancellationToken = default)
 				=> _transform(await _source.ReadAsync(cancellationToken));
 
 			public override ValueTask<bool> WaitToReadAsync(CancellationToken cancellationToken = default)
@@ -43,12 +43,12 @@ public override ValueTask<bool> WaitToReadAsync(CancellationToken cancellationTo
 		/// <summary>
 		/// Transforms the 
 		/// </summary>
-		/// <typeparam name="TIn">The output type of the provided source reader and input type of the transform.</typeparam>
-		/// <typeparam name="TOut">The output type of the transform.</typeparam>
+		/// <typeparam name="T">The output type of the provided source reader and input type of the transform.</typeparam>
+		/// <typeparam name="TResult">The output type of the transform.</typeparam>
 		/// <param name="source">The source channel reader.</param>
 		/// <param name="transform">The transform function.</param>
 		/// <returns>A channel reader representing the tranformed results.</returns>
-		public static ChannelReader<TOut> Transform<TIn, TOut>(this ChannelReader<TIn> source, Func<TIn, TOut> transform)
-			=> new TransformingChannelReader<TIn, TOut>(source, transform);
+		public static ChannelReader<TResult> Transform<T, TResult>(this ChannelReader<T> source, Func<T, TResult> transform)
+			=> new TransformingChannelReader<T, TResult>(source, transform);
 	}
 }

Open.ChannelExtensions/Open.ChannelExtensions.csproj

@@ -19,9 +19,9 @@ Part of the "Open" set of libraries.
     <RepositoryType>git</RepositoryType>
     <PackageTags>channels dotnet threading tasks extensions</PackageTags>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <Version>3.1.0</Version>
+    <Version>3.1.1</Version>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
-    <PackageReleaseNotes>Improved overloads and method standards.  FxCop inspection pass.  Added ChannelReader.ToListAsync().</PackageReleaseNotes>
+    <PackageReleaseNotes>Added TransformChannel class which facilitates providing a channel with different .</PackageReleaseNotes>
     <RepositoryUrl>https://github.com/electricessence/Open.ChannelExtensions</RepositoryUrl>
   </PropertyGroup>
 

Open.ChannelExtensions/TransformChannel.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Diagnostics.Contracts;
+using System.Threading.Channels;
+
+namespace Open.ChannelExtensions
+{
+	/// <summary>
+	/// A channel wrapper that takes the provided channel and transforms them on demand when being read.
+	/// </summary>
+	/// <typeparam name="TWrite">Specifies the type of data that may be written to the channel.</typeparam>
+	/// <typeparam name="TRead">Specifies the type of data that may be read from the channel.</typeparam>
+	public class TransformChannel<TWrite, TRead> : Channel<TWrite, TRead>
+	{
+		/// <summary>
+		/// Creates a channel wrapper that takes the provided channel and transforms them on demand when being read.
+		/// </summary>
+		/// <param name="source">The channel containing the source data.</param>
+		/// <param name="transform">The transform function to be applied to the results when being read.</param>
+		public TransformChannel(Channel<TWrite, TWrite> source, Func<TWrite, TRead> transform)
+		{
+			if (source is null) throw new ArgumentNullException(nameof(source));
+			if (transform is null) throw new ArgumentNullException(nameof(transform));
+			Contract.EndContractBlock();
+
+			Writer = source.Writer;
+			Reader = source.Reader.Transform(transform);
+		}
+	}
+}