anchor.diff:    (let ((values (eval-if-needed listval)))
       (loop 
          for sym in listsym
  -       for val in  values
  -       do (set-walk-through-value-in-multiple sym val listsym values))))
  +       do (set-walk-through-value-in-multiple sym listsym values))))
   
   (defun eval-a-variable (var val)
     "Parse variable definition and set it (or them)." 
  
positive.code:   (funcall *generate* (template 'nothing)))
  (export 'real-next-walk)
  
  (defun set-walk-through-value-in-multiple (name val symbols values)
    (setf (get name 'values) values)
    (setf (get name 'symbols) symbols)
    (setf (get name 'index) -1)
  
negative.code: 
  (defun set-walk-through-value (name values)
    "Set value of variable of type walk-through. Keep list of value and index in symbol's plist."
  ;  (script-debug "set-walk-through-value ~A ~A~%" name (eval-if-needed values))
    (setf (get name 'values) (eval-if-needed values))
    (setf (get name 'index) -1)
    (setf (symbol-value name) 'value-not-set-before-first-call-to-next-step-§->!))
  