anchor.diff:                               (editor-variable-local-indicator var))
                  value)))
         ((:global)
  +       (let ((fn (editor-variable-change-value-hook var)))
  +         (when fn
  +           (funcall fn value)))
          (setf (editor-variable-value var) value)))))
   
   (defun variable-documentation (symbol)
  
positive.code: (defstruct editor-variable
    value
    documentation
    local-indicator)
  
  (defun clear-editor-local-variables (buffer)
    (dolist (symbol *editor-variables*)
  
negative.code:                     (editor-variable-local-indicator
                       (get symbol 'editor-variable)))))
  
  (defmacro define-editor-variable (var &optional value documentation change-value-hook)
    (check-type var symbol)
    `(unless (get ',var 'editor-variable)
       (defvar ,var)
  