anchor.diff:         (eq 'function (car x))
          (not (atom (cadr x)))))
   
  +(defvar *function-atom-sources* (make-hash-table :test #'eq))
  +
  +(defun function-source (x)
  +  (or (functionp x)
  +      (error "Not a function."))
  +  (gethash x *function-atom-sources*))
  +
  +(defun =-function-source (v x) v x (setf (gethash x *function-atom-sources*) v))
  +
   (defun make-lambdas (x)
     (cond
       ((atom x)                  (? (eq '&body x)
  
positive.code:                                   x))
      ((function-expr? (car x))  `(labels ((~ja ,@(make-lambdas (cadar x))))
                                    (~ja ,@(make-lambdas (cdr x)))))
      ((function-expr? x)        `#'(lambda ,@(make-lambdas (cadr x))))
      (t (mapcar #'make-lambdas x))))
  
  (defun quasiquote-expand (x)
  
negative.code: (defun function-native (x) x)
  (defun function-bytecode (x) x (error "Not implemented."))
  (defun =-function-bytecode (v x) v x (error "Not implemented."))
  
  (defun bit-or (a b) (bit-or a b))
  (defun << (x num-bits-to-left) x num-bits-to-left (error "Not implemented."))
  