anchor.diff:        (single body)
           (car body)
         `(let1 it ,(car body)
  +	(declare (ignorable it))
           (ado ,@(cdr body)))))
   
   (mac accum (accfn &body body)
  
positive.code: 
  (mac awhen (expr &body body)
     "Analog of alf but for when"
    `(let1 it ,expr (lf it (progn ,@body)))) ; change name of progn
  
  (mac aand (&rest args)
    "Evaluates each argument one by one. Binds the result of the previous
  
negative.code:   (zerop (mod x y)))
  
  ;;; iteration macros to avoid using loop directly
  (mac repeat (times &body body)
    `(loop repeat ,times do (progn ,@body)))
  
  (mac up (var a b &body body)
    "Evaluates body iterating from a up to b inclusive"
    `(loop for ,var from ,a to ,b do (progn ,@body)))
  