anchor.diff:    "An alist mapping lexical-variables to their values, if known.")
   
   (defparameter *constprop-lambda-copy-limit* 3)
  +(defparameter *constant-fold-modes* (make-hash-table :test 'equal))
   
   (defun constprop (lambda architecture)
     (declare (ignore architecture))
  
positive.code:              (keywordp (symbol))
               (sys.int::%type-check (t fixnum t))
               (float (t t))))
    (setf (get (first x) 'constant-fold-mode) (second x))
    (when (third x)
      (setf (get (first x) 'constant-folder) (third x))))
  
  (defun mark-as-constant-foldable (name)
    (setf (get name 'constant-fold-mode) t))
  
negative.code:     (setf (lambda-information-body form) (cp-form (lambda-information-body form))))
    form)
  
  (defun mark-as-constant-foldable (name &key (mode t) folder)
    (setf (gethash name *constant-fold-modes*) (cons mode folder)))
  
  ;;; Initialize constant folders.
  (dolist (x '((sys.int::%simple-array-length ((satisfies sys.int::%simple-array-p)))
               (char-code (character))
  