OMeta# a .NET meta language
What's nice is that a couple of posts later I noticed a link by Harry Pierson to an attempt by Jeff Moser to port OMeta to the .NET world and to enable the very "meta object protocol" Reginald mentions. Here are the opening bits from Jeff's post (go read the rest):
The bottom line: Languages like Java give you an object protocol: There is one way to do things with objects and classes and interfaces, period. Anything else, like adding generics or annotations, must be done outside of the language, it must be done by the creators of the language.
Languages like Common Lisp and Smalltalk give you a meta object protocol: You can decide for yourself how to do things with objects, classes, interfaces, generic functions, whatever you want. You don’t need to wait for a committee to try something different.
Also check out the code Jeff posted so far (on CodePlex)
What if programming language implementations were object-oriented? What if you wanted to change one itty-bitty part of your favorite language? Say you wanted to add an exponentiation operator (^^). How hard would it be?
Wouldn't it be nice if you could "subclass" a language like C# and then add 5 lines of code to make it work and then use it? What if you could add Ruby-like method_missing support in 20 lines?
What if you could conceive of a new language and start experimenting with it in production code in an hour? What if it leveraged your knowledge of existing frameworks like .NET?