/prog/'s own esoteric language

Fun idea. Let's make our own programming language.
Conditions:
Must be somewhat useful like ABC.
Not limited to characters only. Can include words.
1 function per post.

(import math)

(class Example (object)
  (def (__init__ x y)
    (multiple-def (self.x self.y) (x y)))
  (def angle (property (lambda (self) (math.atan (/ self.y self.x)))))
  (def radius (property (lambda (self) (** (+ (* self.x self.x) (* self.y self.y)) .5) )))
  (def (repr self)
    (% '(Example %s %s)' (repr self.x) (repr self.y)))
)

(print (map (lambda (x) (x.upper)) 'This is the language of my dreams; the forcibly Lisped language Lython... Lisp syntax, Python semantics, object system and library.'))