C# has come a long way since it emerged from Microsoft's mythical "Project Cool" back in 2000. It is the primary language of Microsoft .NET, and has pulled ahead of Visual Basic among professional Windows programmers.
At last week's Tech-Ed conference in Barcelona, C#'s lead architect Anders Hejlsberg drew large audiences for his sessions on the future of the language.
Why LINQ? "It's effectively to remove the impedance mismatch between a programming language and databases," Hejlsberg said. "The whole concept of query and set transformations is one that really has been missing from general purpose programming languages for no good reason. Why is it that I can query data when it sits in a database but the minute I fetch it into memory I can't query it at all? I can write primitive for loops and if statements, but I have nothing that even approaches the declarative query power that you see in SQL or XQuery?"
LINQ is built on lower-level language features including lambda expressions and expression trees (which allow lambda expressions to be represented as data). Hejlsberg said much of this is borrowed from functional programming. "In C# 3.0 we are looking at a lot of research that has occurred in functional programming languages. Lisp is the classical grandfather of a lot of functional programming, but also Haskell and ML."
When C# first appeared, it looked in some respects uncannily similar to Java. Since then, Java's designers seem to have returned the compliment, with features such as autoboxing (treating simple types as objects) and liberal use of annotations seeming to echo similar features in C#. Are the two languages becoming one and the same?
"If I look at where the innovation is occurring, I would venture to say that we're being a bit more innovative these days than is the case in the Java world," he said. "Java has generics, but they chose to do it in a different way where it's really just compile time sugar that goes away, and they don't in my mind realise all the full benefits of not just a generic language but a generic type system in the runtime. I think we're pulling ahead a bit now by pulling all these functional concepts into C#, and language integrated query is an innovation that is only in C#."
Java on the other hand is cross-platform and is being open sourced. Then again, there is Mono, an open-source implementation of C# and the .NET framework sponsored by Novell. Does Microsoft support or oppose this competition?
"I welcome other implementations, and the Mono guys have participated in the standardisation process in ECMA. We remain committed to the standardisation process with .NET and C#, wherever that may take us."
The trouble is, while this welcome may be true of the language and core runtime, Microsoft's attitude to the non-standardised parts of its Framework, including the popular ASP.NET web platform, is less clear. The recently announced agreement with Novell gives little real comfort, other than to a narrow range of Novell customers, and may even increase the suspicion that Microsoft may one day cause legal problems for Mono. Otherwise, why is there need for a patent agreement? Microsoft needs to do more before cross-platform C# can reach the mainstream. ®