Joe Hummel, PhDJoe Hummel, PhD Professor: U. of Illinois, Chicago Consultant: Joe Hummel, Inc. Trainer: Pluralsight Microsoft MVP C++ Chicago-based, one daughter adopted from China

Joe Hummel, PhD

@joehummel

[email protected]

http://www.joehummel.net/downloads.html

the compiler is at your service

Chicago Code Camp 2014

mailto:[email protected]


Joe Hummel, PhD Professor: U. of Illinois, Chicago

Consultant: Joe Hummel, Inc.

Trainer: Pluralsight

Microsoft MVP C++

Chicago-based, one daughter adopted from China (now 12!)

Avid sailor

Chicago Code Camp 2014 2 Project Roslyn


What is Project Roslyn?

The ".NET Compiler Platform"

Replacement of existing .NET compilers with new ones

csc for C#

vbc for VB.NET


class C { . . . }

class C { . . . }

class C { . . . }

000101010 101010101 010101010

csc

Why is this a big deal?

Risky if they get this wrong, folks can't build their apps

if they get this wrong, MSFT can't build their apps


What's the benefit?

Faster turnaround on new features inside and outside MSFT

Grow the Visual Studio ecosystem MUCH easier to build new tools

MUCH easier to extend Visual Studio, C# and VB

MUCH easier to try out new ideas


Status preview release

open source!

http://roslyn.codeplex.com


http://roslyn.codeplex.com/

Open source?

Yes, open source! Apache license 2.0

You are free to GIT, fork, modify, rebuild, deploy

Anders did this on stage @ Build 2014



C# and VB compilers were black boxes predefined switches only way to interact…


csc

> csc.exe main.cs /o /warn:4


The compilers are now white boxes

You can: obtain information about a program

modify a program syntactically / semantically

impact the compilation process

change the compiler itself!

12 Chicago Code Camp 2014

Project Roslyn

csc

Roslyn

13 Chicago Code Camp 2014

Project Roslyn

csc

"Call me every time you see an

identifier…" (because I'm

renaming all global variables)

"Emit this code instead…"

(I'm targeting specific HW)

// translate resource strings:

foreach(Project p)

foreach(Document d)

foreach(Resource r)

replace(r, r');

Roslyn

What can we do with this capability?

Infinite possibilities: better tools — refactoring, analysis, …

better enforcement of coding standards

add scripting support to your app

target new platforms

language research — DSLs, …

compiler research

…



Front-end vs. Back-end

Front-end deals with syntax ― "grammar"

Back-end deals with semantics ― "meaning"



Source

language

Parsing

Assembly

language

Lexical Analysis Compiler

Semantic Analysis

High-level Optimizer

Code Gen

Low-level Optimizer

tokens

IR IR' IR''

IR'''

// comment if (x>100) x = 100;

if, (, x, >, 100, ), x, =, …

syntax

errors

semantic

errors

Roslyn Intermediate Representation (IR)

Abstract Syntax Tree (AST)

Symbol Table


+

GCD program

0 "int", type, …

1 "void", type, …

2 …

3 "getint", funct, type: 0, …

4 "putint", funct, type: 1, …

5 "i", var, type: 0, …

6 "j", var, type: 0, …

… …

How to learn Roslyn AST?

Use the Roslyn Syntax Visualizer! Open a project

Open a source file

View menu…

>> Other Windows

>> Roslyn Syntax Visualizer



Roslyn is BIG There are many APIs…

There is the source code itself…


+

Start small

Let’s create a simple diagnostic that warns about empty catch blocks…


Step 1: Create new project…

>> Roslyn

>> Diagnostic with Code Fix

Name

>> EmptyCatchDiagnostic


Step 2: Create Syntax Node Analyzer

to detect empty catches


public class DiagnosticAnalyzer : ISyntaxNodeAnalyzer<SyntaxKind> { . . . public ImmutableArray<SyntaxKind> SyntaxKindsOfInterest { get { return ImmutableArray.Create( SyntaxKind.CatchClause ); } } // only called for things of interest: public void AnalyzeNode(SyntaxNode node, ...) { var catchBlock = node as CatchClauseSyntax; if (catchBlock.Block.Statements.Count == 0) // empty! { var diagnostic = Diagnostic.Create(...); // create warning: addDiagnostic(diagnostic); // display: } }

Step 3: Create Code Fix Provider

to optionally correct problem…


internal class CodeFixProvider : ICodeFixProvider { . . // only called for things of interest: public async Task<…> GetFixesAsync(Document document, ...) { var root = await document.GetSyntaxRootAsync(cancellationToken); var token = root.FindToken(span.Start); // catch keyword: if (!token.IsKind(SyntaxKind.CatchKeyword)) // sanity check: return null; var catchBlock = (CatchClauseSyntax)token.Parent; var throwStmt = SyntaxFactory.ThrowStatement(); var newStmts = new SyntaxList<StatementSyntax>().Add(throwStmt); var newBlock = SyntaxFactory.Block().WithStatements(newStmts); var newCatchBlock = SyntaxFactory.CatchClause(). WithBlock(newBlock). WithAdditionalAnnotations(Formatter.Annotation); var newRoot = root.ReplaceNode(catchBlock, newCatchBlock); return new[] { CodeAction.Create("throw", document.WithSyntaxRoot(newRoot)) }; }

Step 4: Run!

A .vsix installer is built

A new instance of VS is started

The .vsix is installed

Open a project and test…



Caveats!

You will be *replacing* your C# and VB compilers Are you sure?

Scripting support is currently missing i.e. using Roslyn to add C# / VB scripting to your app

MSFT is "re-evaluating design"


Download "End User Preview / SDK Preview" 1. http://msdn.microsoft.com/en-gb/roslyn

2. Get the Preview


http://msdn.microsoft.com/en-gb/roslyn




Unzip SDK

Install: 1. End User Preview

2. Project Templates

3. Syntax Visualizer

4. Roslyn Experimental Hive


Install Microsoft Visual Studio 2013 SDK



Thank you for attending! Joe Hummel, PhD

Email: [email protected]

Materials: http://www.joehummel.net/downloads.html

For more information on Roslyn: Docs / FAQ:

http://roslyn.codeplex.com/documentation

Build 2014 on Channel 9

The Future of C#

https://channel9.msdn.com/Events/Build/2014/2-577


mailto:[email protected]









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Joe Hummel, PhDJoe Hummel, PhD Professor: U. of Illinois, Chicago Consultant: Joe Hummel, Inc. Trainer: Pluralsight Microsoft MVP C++ Chicago-based, one daughter adopted from China