1. The Evolution of Modern Computer Languages C#, Java, Ruby and the Rise of DSLs by Daniel Leuck

2. What are Some of the Trends in Computer Languages? • Many things that used to handled with libraries are now being handled at the language level. • The line between statically typed systems languages and scripting languages is getting blurred. • Heavier use of declarative programming, both embedded within and used alongside general purpose imperative/OO, is on the rise. • Complex querying capabilities, once the exclusive domain of SQL, are moving into general purpose languages. • Many languages are becoming more malleable by allowing embedded DSLs or supporting dialects. • Testing capabilities are moving into the languages.

3. Key C# Language Features Introduced in C# 3.0 • LINQThe ability to write terse, perspicuous and statically typed queries directly within C#int[] nums= { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };varlowNums = from n in nums where n < 5 select n; • Type Inference (see above) • Object InitializersEnable declarative construction of object graphs • Extender Methods“Inject” methods from a static class into other classes. • Lots of other syntactic sugar

4. Declarative UIs with C# This has long been supported by languages with named parameters such as Python and Ruby. varlightBorderColor = Color.FromArgb(102, 102, 200); vardarkBorderColor = Color.FromArgb(60, 60, 255); button.Painter = new Painter { GradientFill = new GradientFill { ColorA = Color.FromArgb(192, 192, 255), ColorB = Color.Navy }, MultiBorder = new MultiBorder { OuterBorderSize = new Padding(1), TopOuterColor = lightBorderColor, LeftOuterColor = lightBorderColor, BottomOuterColor = darkBorderColor, RightOuterColor = darkBorderColor }, ForeColor = Color.FromArgb(255, 255, 230) };

5. C# 4 • Recent posts on MSDN indicate that the DLR will become part of the standard library, and the generalized DLR AST will be accessible from within the C# language. • This means C# 4 will likely support some really cool meta programming features. Possibilities include dialects, language specific methods, dynamic code blocks. The imagination runs wild 

6. Java 5, 6 and 7 • Although Java 5 introduced some nice new language features it lags behind C# in terms of language innovation. It does do some things better such as enums, which are actually special classes versus dressed up scalars • Java 6 didn’t introduce any language improvement.  • The current Java 7 proposal includes many language improvements • Closures • Native XML support similar to ActionScript • Superpackages and modules • Runtime generics • Type annotations (e.g. NotNull) • C# like support for properties and events at the language levelex. name = person->name; • Try / catch enhancements • Many others (applicability of operators to many class types, static method extension, etc.)

7. Ruby • One of today’s most popular scripting languages, especially for Web Development (Ruby on Rails) • 100% OO – Everything is an object, and everything is highly malleable • Borrows from Python and Perl – Simple examples:puts "Hello World"-199.abs # 199"ruby is cool".length # 12"Dan".index("a") # 1"Nice Day Isn't It?".downcase.split(//).sort.uniq.join # " '?acdeinsty” • Supports some meta-programming capabilities • Features coming in Ruby 1.9 include new variable scopes, more advanced argument pattern matching (multiple splats, mixing mixed optional and mandatory arguments, etc.) and improved exception handling • Matz is very tight lipped about Ruby 2. It may support optional typing. It will likely be a clean up release rather than a radical, backwards capability breaking release like Perl 6.

8. New Language: Cobra • A modern Python / Ruby like language with contracts, language level support for unit testing and optional typing def act(ctx as Context) require # Requirements can speak to… .isActive # the state of the current object ctx.isActive # the state of the arguments ensure # Can refer to 'old’ values in 'ensure’ .actionCount == old .actionCount + 1 body _actionCount += 1

9. DSLs • Domain Specific Languages are languages specific to a problem domain, a particular problem representation or a particular solution technique. • They are often embedded in strings, but some languages now support their use in embedded blocks which are verified by the interpreter or compiler. • Some tools such as JetBrains MPS are emerging to assist in the design of DSLs

10. Summary • General purpose programming languages are getting easier to use as terser, more natural representations of common constructs are added • Most recent enhancements to popular programming languages such as C# and Java are syntactic sugar, but are still very helpful • Languages are getting larger as more functionality that used to be the domain of libraries are getting pulled into the language itself. • More and more programming is becoming declarative. • In many areas unit testing and contracts are in, while static typing is out