Hello, I'm please to announce that I will be giving a 90 minutes session at the next ACCU conference, in Oxford. The abstract is given below: Meta-circularity... and vice-versa As complexity increases, one often feels limited by the use of a single language, and incorporates new technology in order to express the original problem more abstractly, more precisely, and design solutions more efficiently. Using better-suited languages also has the advantage of letting you think about your problem in new and different ways, perhaps ways that you had not thought of before. It is thus no surprise to see the profusion of new languages that we face today, notably scripting and domain-specific ones. But then, why the need for all this new and different technology? Wouldn't it be better if your primary language could evolve the way you want it to? And why is it not generally possible? Perhaps, because your primary language is not really extensible... Meta-linguistic abstraction, that is, the art of language design plays a capital role in computer science because we have the ability to actually implement the languages we design, for instance by creating interperters for them. A fundamental idea in this context is that an interpreter is just another program (by extension, one could argue that any program is an interpreter for a particular language). In this session, we will revive a historical moment in computer science: the birth of meta-circularity. When, in 1958, John McCarthy invented Lisp, he hadn't foreseen that given the core 7 operators of the language, it was possible to write Lisp in itself, by way of an interpreter. The practical implication of meta-circularity is that a meta-circular language gives you direct control over the semantics of the language itself, and as a consequence, means to modify or extend it. No wonder, then, why lispers never felt the need for external DSLs, scripting languages, XML or whatever. The reason is that Lisp, being extensible, can do all that by itself. Lisp is, by essence, the "programmable programming language". -- Resistance is futile. You will be jazzimilated. El Didou