anchor.diff:  (defun funinfo-arg-pos (fi x)
     (position x (funinfo-args fi) :test #'eq))
   
  -;;;; FREE VARIABLES
  -
  -(defun funinfo-free-var? (fi var)
  -  (member var (funinfo-free-vars fi) :test #'eq))
  -
  -(defun funinfo-add-free-var (fi var)
  -  (adjoin! var (funinfo-free-vars fi) :test #'eq)
  -  var)
  -
  -;;;; ARGUMENTS & ENVIRONMENT
  -
   (defun funinfo-local-args (fi)
     (remove-if [funinfo-lexical? fi _] (funinfo-args fi)))
  +
  +
  +;;;; ARGUMENTS & VARIABLES
   
   (defun funinfo-var? (fi x)
     (& x (atom x)
  
positive.code:      (not (funinfo-used-var? fi x))
       (+! (funinfo-used-vars fi) (list x))))
  
  (defun funinfo-get-name (fi)
    (| (funinfo-name fi)
       (funinfo-get-name (funinfo-parent fi))))
  
  (defun funinfo-immutable? (fi x)
    (member x (funinfo-immutables fi) :test #'eq))
  
negative.code: ;;;;; tré – Copyright (c) 2006–2007,2009–2013 Sven Michael Klose <pixel@copei.de>
  
  
  ;;;; FUNCTION NAME
  
  (defun funinfo-get-name (fi)
    (| (funinfo-name fi)
       (funinfo-get-name (funinfo-parent fi))))
  
  ;;;; ARGUMENTS
  
  