Initial implementation

.editorconfig

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+root = true
+
+[*.{cs,md}]
+indent_style=spaces
+indent_size=2
+encoding=utf-8

.github/workflows/publish-release.yml

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+name: Publish Release
+
+on:
+  push:
+    branches:
+      - main
+      - master
+
+jobs:
+  publish-release:
+    # ubuntu-latest provides many dependencies.
+    # See: https://github.com/actions/virtual-environments/blob/master/images/linux/Ubuntu1804-README.md
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout latest commit
+        uses: actions/checkout@v2
+      - name: Install CICEE
+        run: dotnet tool install -g cicee || dotnet tool update -g cicee
+      - name: Execute publish script - Publish project artifacts
+        run: cicee exec -c ci/bin/publish.sh
+        env:
+          NUGET_API_KEY: ${{secrets.NUGET_API_KEY}}
+          NUGET_SOURCE: ${{secrets.NUGET_SOURCE}}
+          RELEASE_ENVIRONMENT: true

.github/workflows/validate-project.yml

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+name: Validate Project
+
+on: [pull_request]
+
+jobs:
+  validate-project:
+    # ubuntu-latest provides many dependencies.
+    # See: https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-README.md
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout latest commit
+        uses: actions/checkout@v2
+      - name: Install CICEE
+        run: dotnet tool install -g cicee || dotnet tool update -g cicee
+      - name: Execute verification script - Validate source
+        run: cicee exec -c ci/bin/validate.sh
+        env:
+          NUGET_API_KEY: ${{secrets.NUGET_API_KEY}}
+          NUGET_SOURCE: ${{secrets.NUGET_SOURCE}}
+          RELEASE_ENVIRONMENT: false
+      - name: Execute compose script - Perform dry-run composition
+        run: cicee exec -c ci/bin/compose.sh
+        env:
+          NUGET_API_KEY: ${{secrets.NUGET_API_KEY}}
+          NUGET_SOURCE: ${{secrets.NUGET_SOURCE}}
+          RELEASE_ENVIRONMENT: false

.gitignore

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+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+
+# User-specific files
+*.suo
+*.user
+*.sln.docstates
+.vs/
+
+# Build results
+
+[Dd]ebug/
+[Rr]elease/
+x64/
+[Bb]in/
+[Oo]bj/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+*_i.c
+*_p.c
+*_i.h
+*.ilk
+*.meta
+*.obj
+*.pch
+*.pdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*.log
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.log
+*.svclog
+*.scc
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opensdf
+*.sdf
+*.cachefile
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.Publish.xml
+*.pubxml
+*.azurePubxml
+
+# NuGet Packages Directory
+## TODO: If you have NuGet Package Restore enabled, uncomment the next line
+packages/
+## TODO: If the tool you use requires repositories.config, also uncomment the next line
+!packages/repositories.config
+
+# Windows Azure Build Output
+csx/
+*.build.csdef
+
+# Windows Store app package directory
+AppPackages/
+
+# Others
+sql/
+*.Cache
+ClientBin/
+[Ss]tyle[Cc]op.*
+![Ss]tyle[Cc]op.targets
+~$*
+*~
+*.dbmdl
+*.[Pp]ublish.xml
+
+*.publishsettings
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file to a newer
+# Visual Studio version. Backup files are not needed, because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+
+# SQL Server files
+App_Data/*.mdf
+App_Data/*.ldf
+
+# =========================
+# Windows detritus
+# =========================
+
+# Windows image file caches
+Thumbs.db
+ehthumbs.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Mac desktop service store files
+.DS_Store
+
+_NCrunch*
+
+!ci/bin/

README.md

@@ -1,2 +1,119 @@
-# task-chaining
-Monadic-style chaining for C# Tasks
+# RLC.TaskChaining
+
+Monadic-style chaining for C# Tasks.
+
+## Rationale
+
+Asynchronous code (particularly in C#) typically relies on using the `async`/`await` feature introduced in C# 5.0.  This has a lot of benefits, but it unfortunately tends to push code into an imperative style.  This library aims to make writing asychronous functional code easier, cleaner, and less error-prone using extensions to `System.Threading.Tasks`.
+
+## Installation
+
+Install RLC.TaskChaining as a NuGet package via an IDE package manager or using the command-line instructions at [nuget.org][].
+
+## API
+
+### Chaining
+
+#### Then
+
+Once a `Task<T>` has been created, successive operations can be chained using the `Then` method.
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Task.FromResult("https://www.google.com")  // Task<string>
+  .Then(client.GetAsync)                   // Task<HttpResponseMessage>
+  .Then(response => response.StatusCode);  // Task<System.Net.HttpStatusCode>
+```
+
+#### Catch
+
+When a `Task<T>` enters a faulted state, the `Catch` method can be used to return the `Task<T>` to a non-faulted state.
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Task.FromResult("not-a-url")              // Task<string>
+  .Then(client.GetAsync)                  // Task<HttpResponseMessage> but FAULTED
+  .Catch(exception => exception.Message)  // Task<string> and NOT FAULTED
+  .Then(message => message.Length)        // Task<int>
+```
+
+Note that it's entirely possible for a `Catch` method to cause the `Task<T>` to remain in a faulted state, e.g. if you only wanted to recover into a non-faulted state if a particular exception type occurred.
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Task.FromResult("not-a-url")          // Task<string>
+  .Then(client.GetAsync)              // Task<HttpResponseMessage> but FAULTED
+  .Catch(exception => exception is NullReferenceException
+    ? exception.Message
+    : Task.FromException(exception))  // Task<string> but STILL FAULTED if anything other than NullReferenceException occurred
+  .Then(message => message.Length)    // Task<int>
+```
+
+#### IfFulfilled/IfRejected/Tap
+
+The `IfFulfilled` and `IfRejected` methods can be used to perform side effects such as logging when the `Promise<T>` is in the fulfilled or faulted state, respectively.
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Promise<string>.Resolve("https://www.google.com/")
+  .Then(client.GetAsync)
+  .IfFulfilled(response => _logger.LogDebug("Got response {Response}", response)
+  .Then(response => response.StatusCode);
+```
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Promise<string>.Resolve("not-a-url")
+  .Then(client.GetAsync)
+  .IfRejected(exception => _logger.LogException(exception, "Failed to get URL")
+  .Catch(exception => exception.Message)
+  .Then(message => message.Length);
+```
+
+The `Tap` method takes both an `onFulfilled` and `onRejected` `Action` in the event that you want to perform some side effect on both sides of the `Promise` at a single time.
+
+```c#
+HttpClient client;  // Assuming this is coming from an HttpClientFactory or injected or whatever
+
+Promise<string>.Resolve(someExternalUrl)
+  .Then(client.GetAsync)
+  .Tap(
+    response => _logger.LogDebug("Got response {Response}", response),
+    exception => _logger.LogException(exception, "Failed to get URL")
+  )
+```
+
+### Static Methods
+
+There are some convenience methods on `TaskExtras` that are useful when transitioning between the fulfilled and faulted states.
+
+#### RejectIf
+
+`RejectIf` can be used to transition into a faulted state based on some `Predicate<T>`.
+
+```c#
+Task.FromResult(1)
+  .Then(TaskExtras.RejectIf(
+    value => value % 2 == 0,
+    value => new Exception($"{nameof(value)} was not even")
+  ));
+```
+
+#### ResolveIf
+
+`ResolveIf` can be used to transition from a faulted state to a fulfilled state based on some `Predicate<Exception>`.
+
+```c#
+Task.FromException<int>(new ArgumentException())
+  .Catch(TaskExtras.ResolveIf(
+    exception => exception is ArgumentException,
+    exception => exception.Message.Length
+  ))
+```
+
+[nuget.org]: https://www.nuget.org/packages/RLC.TaskChaining/

TaskChaining.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30114.105
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaskChaining", "src\TaskChaining.csproj", "{68ECCC63-041F-4224-9FF7-CDA13C547DCB}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaskChainingTests", "tests\unit\TaskChainingTests.csproj", "{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{68ECCC63-041F-4224-9FF7-CDA13C547DCB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{68ECCC63-041F-4224-9FF7-CDA13C547DCB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{68ECCC63-041F-4224-9FF7-CDA13C547DCB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{68ECCC63-041F-4224-9FF7-CDA13C547DCB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(NestedProjects) = preSolution
+		{0F9F7E48-C6A5-4558-A5F5-8F9E5B4690B1} = {26E4FD11-2DB7-4E0D-841C-5ADC5760A46C}
+	EndGlobalSection
+EndGlobal

ci/Dockerfile

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+# Universal, base image
+#   See: https://registry.hub.docker.com/_/microsoft-vscode-devcontainers?tab=description
+#   See: https://github.com/microsoft/vscode-dev-containers/tree/master/containers/codespaces-linux
+FROM mcr.microsoft.com/vscode/devcontainers/universal:linux AS build-environment
+
+USER root
+
+# Install CICEE and make sure .NET global tools are added to path
+RUN dotnet tool install -g cicee
+ENV PATH="${PATH}:/root/.dotnet/tools"