Adding syntax to the CPython interpreter

If only there was a language that let you modify the interpreter on the fly so you could do this as part of normal execution...

Python can actually do this using "# coding:", albeit less elegantly than lisp.

I would say it's a good thing, I don't want to see a hundred of half baked, badly tested and vaguely document DSL with no decent tooling support.

Can you provide some more info / links regarding the “# coding:” feature? I wasn’t able to find anything.