anchor.diff:    ; List of arguments.
     (args       nil)
   
  -  ; Argument expansion description.
  -  ;
  -  ; Tells, where arguments must be placed on the stack or if they must be
  -  ; placed on a rest list. This is used to insert argument passing instructions.
  -  ;(argument-places nil)
  -
  -  ; Called functions.
  -  ;(callees nil)
  -
  -  ; Total size of stack with arguments and local variables.
  -  ;(stack-size nil)
  -
     ; List of variables defined outside the function.
     (free-vars  nil)
   
  
positive.code: 
  (defun funinfo-push-env (fi forms)
    "Open new environment."
    (push forms (funinfo-env fi))
    nil)
   
  (defun funinfo-pop-env (fi)
    "Close environment."
    (pop (funinfo-env fi))
    nil)
  
  (defun funinfo-env-add-args (fi args)
    "Add variables to the current environment."
    (setf (car (funinfo-env fi)) (append (car (funinfo-env fi)) args))
    nil)
  
  (defun funinfo-env-add-arg (fi arg)
    "Add variables to the current environment."
  
negative.code: (defun funinfo-add-free-var (fi var)
    "Add free variable."
    (push (funinfo-free-vars fi) var)
    var)
  
  (defun funinfo-env-this (fi)
    "Get current environment description."
  