.NET Programming Language PragmaticsAndrew PetersMindscape

DEV321

AgendaThe .NET Language EcosystemLanguage Design SpectrumsA Tour of Language FeaturesInteroperabilityDriving the Future

.NET Language EcosystemCLR Refresher

Common Type system

Class Loader, GC, JIT, Execution Support

Security

Base Class Libraries

Common Language Runtime

C# VB.NET …

.NET Language EcosystemStandards based

ECMA/ISO StandardizedCLR + Parts of the BCL + C# languageUp to the 4th edition

Common Type SystemContract for types and interoperabilityRules for wide reachObject-oriented in flavourFunctional + Dynamic possible

.NET Language EcosystemMulti-language

Version 1.x (2000-03)Focused on statically typed OO languages (C#, VB.NET, Eiffel, C++)

Version 2.0 (2005) Better support for Functional languages (Generics, faster and relaxed delegates)Enabled support for Dynamic Languages (LCG, better delegate support)

Version 3.x (2008)Dynamic languages (DLR)Flexible type systems

Language Spectrums Design Pressures

ProductivityLine for line: developer productivity

Application paradigm shifts“Cloud” programmingWeb/Rich Client/User ExperienceUnstructured data

Hardware changesConcurrency and Parallelism

Developer happiness

Language Spectrums Safe vs. Useful

Unsafe Safe

Useful

Not Useful

C#, C++, … V.Next#

Haskell

Language Spectrums Static to Dynamic

Static (C#, Java)

Dynamic (Python)

Functional (F#,

Haskell)

Language Feature TourStatic OO Languages

Statically TypedType system is strictly enforced at compile timeTypically strongly typed (adds runtime checks)

Encapsulation and ReuseVisibilityPolymorphismContracts

Problems & MisconceptionsType safety == safe programComplicated program typesContracts must be known at compile timeCan be verbose

Language Feature TourFunctional Languages

Generally more “safe”Less (or no) side effects

Mathematical roots Interesting Language Features

Higher-order & first-class functionsLazy evaluationConcurrent

Problems & MisconceptionsPoor AdoptionHard – requires mindset shift

F#

demo

Language Feature TourDynamic Languages

Flexible type systemsDynamically typedIndispensable for apps with dynamic behavior

Rapid application developmentREPL (Read Evaluate Print Loop)Focus on domain problem, not code

Adapts well to unstructured dataGreat for the “cloud”

Great extensibility experienceAllow scripting of your apps

Language Feature TourDynamic Languages

Interesting language featuresFunctions as objectsAd-hoc relationships (mixin’s)Duck typingMeta-programming

Problems & MisconceptionsDelays type checking to runtimeeval() is a poor substituteJury is out on “less bugs” argument

IronPythonIronRuby

demo

.NET Language EcosystemCLR Refresher

Common Type system

Class Loader, GC, JIT, Execution Support

Security

Base Class Libraries

Common Language Runtime

C# VB.NET …

.NET Language EcosystemCLR Refresher

Common Type system

Class Loader, GC, JIT, Execution Support

Security

Base Class Libraries

Common Language Runtime

C# VB.NET IronPython

DLR Runtime

Language Spectrums Static to Dynamic: Hybrid languages

Static

DynamicFunctional

Language Spectrums Safe vs. Useful

Unsafe Safe

Useful

Not Useful

C#, C++, …

Haskell

STMLINQ

Driving the FutureVB.NET 9 and C# 3.0

Leverages features from both Dynamic and Functional languages

The Erik Meijer mantra: “Static typing where possible, dynamic typing when needed”“Looks a lot like”: integrating dynamic features in to a static language like C#Great for three-tier

STM (Software Transactional Memory)LINQ: Don’t consolidate, comprehend!

VB 9

demo

VB X

Joel Pobar

demo

ConclusionWe’re seeing a convergence of dynamic and static approaches.Choose the right tool for the jobLearning different languages makes us better

Call to action: Learn a dynamic language

Resourceshttp://research.microsoft.com/~emeijer/http://www.iunknown.com/http://blogs.msdn.com/joelpob/http://research.microsoft.com/fsharp/fsharp.aspxhttp://www.ironpython.com/

Evaluation Forms

Questions?

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