Lambda the Ultimate

One of the future additions to C# announced by Anders Hejlsberg in this entertaining video from 2008 is Compiler as a Service. By that he means the ability to eval code strings (and I'm guessing that this will also be integrated with C#'s built-in AST objects).

He shows this off at around minute 59, to great effect and great excitement by the audience. It feels like an inflection point. There probably won't be another REPL-less language from now on.

I predict that after that, they'll add hygienic macros and quasisyntax.