Background

A programming ecosystem is only as strong and healthy, as its open source community.

The difficult stuff

• static/semantic code analysis
• C# development without Visual Studio
• building Visual Studio extensions
• emitting code dynamically
• automation with C#

Low entry barriers

Move Class to File

Roslyn based community OSS projects

Omnisharp

• Intellisense and language services
• Navigation (go to definition, go to implementation, find usages and so on)
• Code Lens ($13k feature)
• Code Issues and refactorings
• Formatting

scriptcs

• One of the most popular community C#/.NET OSS projects in recent years
• Enables rich experience around C# scripting
• contains a C# REPL
• http://scriptcs.net

Script

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void PrintText(string txt) 
{
    Console.WriteLine(txt);
}

class Item 
{
    public int Quantity {get; set;}
}

var test = new Item();
test.Quantity = 100;

PrintText("I have " + test.Quantity + " items".);

REPL

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C:> scriptcs.exe
scriptcs (ctrl-c or blank to exit)

> var message = "Hello, world!";
> Console.WriteLine(message);
Hello, world!
> 

Stylecop Analyzers

• An implementation of StyleCop rules using Roslyn
• https://github.com/DotNetAnalyzers/StyleCopAnalyzers

Refactoring Essentials

• A set of analyzers and refactorings that originated from the NRefactory project
• http://vsrefactoringessentials.com
• https://github.com/icsharpcode/refactoringessentials

Code Cracker

• An analyzer library for C# and VB that uses Roslyn to produce refactorings, code analysis, and other cool things
• https://github.com/code-cracker/code-cracker

C# based build tools / task runners

• Cake - runs on Roslyn
• bau - runs on scriptcs
• https://github.com/bau-build/bau
• https://github.com/cake-build/cake

Cake sample (csx file)

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Task("Run-Unit-Tests")
    .IsDependentOn("Build")
    .Does(() =>
{
    NUnit("./src/**/bin/" + configuration + "/*.Tests.dll");
});

Bau sample (csx file)

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var bau = Require<Bau>();
bau.MSBuild("build").Do(msb =>
{
    msb.MSBuildVersion = "net45";
    msb.MSBuildArchitecture = ProcessorArchitecture.X86;
    msb.Solution = solution;
    msb.Targets = new[] { "Clean", "Build", };
    msb.Properties = new { Configuration = "Release" };
});

Rocks

• A mocking library based on Roslyn
• Much easier process than using System.Reflection.Emit
• Able to pregenerate mocks (instead of creating them during test runtime)
• https://github.com/JasonBock/Rocks

Rocks sample

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public interface IFoo
{
    int Bar();
}

var rock = Rock.Create<IFoo>();
rock.Handle(_ => _.Bar()).Returns(5);
var mockedFoo = rock.Make();

mockedFoo.Bar().ShouldEqual(5);
rock.Verify();

ConfigR

• allows you to use CSX files (C# scripts) to write your project’s configuration
• configuration can be strongly typed
• configuration is no longer purely static (configuration can be an app itself)
• https://github.com/config-r/config-r

CSX config

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Add("Count", 10);

Application

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void Main(string[] args)
{ 
    var count = Config.Global.Get<int>("Count");
}

LINQPad.CodeAnalysis

• Roslyn syntax tree visualization for LINQPad
• https://github.com/daveaglick/LINQPad.CodeAnalysis

Compilify

• A platform allowing you to execute C# code in the browser
• Any errors/diagnostics will be displayed as you type
• Each snippet can be saved and shared with others via a unique URL
• https://github.com/jrusbatch/compilify

Sky's the limit