anchor.diff:    (values (copy-while pred x)
   		  (remove-if pred x)))
   
  -(defmacro with (alst &body body)
  +(defmacro with (lst &body body)
     (unless body
   	(error "body expected"))
     (labels ((sub (x)
  
positive.code:                 `((with ,x
  					,@body))
                  body)))
      (let* ((plc (car alst))
             (val (cadr alst)))
        (?
  	    (cons? plc) `(multiple-value-bind ,plc ,val
  
negative.code: ;;;;; tré – Copyright (c) 2005–2013 Sven Michael Klose <pixel@copei.de>
  
  (defun copy-while (pred x)
    (& x (funcall pred (car x))
  