THE FUTURE OF C# KEVIN PILCH-BISSON MADS TORGERSEN

PROJECT ROSLYN A reimplementation of C# and VB compilers In C# and VB With rich public APIs On CodePlex

WHY ROSLYN?

ROSLYN DEMO Rich IDE experiences Custom diagnostics New language features

RICH IDE EXPERIENCES Inline Rename with conflict detection More refactorings:  Introduce local  Inline temp Lightbulbs to quickly fix up your code Small improvements throughout:  Colorization in quick info, signature help, outlining tooltips  Smarter case matching in Completion

CUSTOM DIAGNOSTICS Easily detect common coding problems Run live in the IDE Can attach “quick fixes” to them as well Run as part of command line/team builds Distribute together with a library on NuGet

LANGUAGE FEATURES Using static members using System.Console; … Write(4); Primary Constructors class Point(int x, int y) { … } Auto-property Initializers public int X { get; set; } = x; Getter-only auto-properties public int Y { get; } = y; Index initializers new JObject { ["x"] = 3, ["y"] = 4 } Declaration Expressions int.TryParse(s, out var x); Await in catch/finally try { … } catch { await … } finally { await … } Exception Filters catch (E e) if (e.Count == 0) { } Null Propagation Operator customer?.Orders?[5].Price

CALL TO ACTION Use the IDE and language features Dip your toes in custom diagnostics Consider forking the compiler source Give us feedback

ROSLYN, C# AND VB RESOURCES