anchor.diff:  (defvar lisp-x 2)
   (assert-eql 12 {% ~lisp-x + 10 %})
   (assert-eql 6 {% ~(+ lisp-x {% 2 * ~lisp-x %}) %})
  -(assert-eql "%" {% "%" %})
  +;(assert-eql "%" {% "%" %})
   
   ;; map
   
  
positive.code: 
  (defclass <foo>)
  (defvar foo (<foo>))
  (assert-eql (slot foo "slot1") null)
  (assert-eql (slot foo "slot2") null)
  (set-slot foo "slot1" 1)
  (assert-eql (slot foo "slot1") 1)
  (assert-eql (slot foo "slot2") null)
  (set-slot foo "slot1" null)
  (assert-eql (slot foo "slot1") null)
  (assert-eql (slot foo "slot2") null)
  
  (assert (has-slot foo "slot1"))
  (assert (not (has-slot foo "slot2")))
  
  (defclass <z> (a b c))
  (defvar z (<z>))
  (assert-eql (.a z) null)
  (assert-eql (.b z) null)
  (assert-eql (.c z) null)
  (set (.a z) 1)
  (set (.b z) 2)
  (set (.c z) 3)
  
negative.code: 
  (defun foo () 12)
  (assert #'foo)
  (assert-eq #'foo (function foo))
  (assert-eql (funcall #'foo) 12)
  
  ;; Escape functions
  
  (assert-eq null (block x 13 (return-from x) 12))
  (assert-eql 1 (block x (return-from x 1)))
  (assert-eql 1 (block x (block y (return-from x 1))))
  (assert-eql 2 (block x (block y 2)))
  