There's a lot of Scheme-ish things available: setters, templates (aka macros but with changeable quoting: ` ' @), continuations.

I've added a few more tricks: computed variables (like SECONDS or RANDOM which dynamically get/set a value) and reader operators (which are the heart of infix "functions" and get to rewrite source code expressions, | being the obvious one for a shell).

All available to the user -- nobody wants to be writing stuff in C! :)