anchor.diff:          (augment-walkenv! env :variable (name-of parsed) parsed)))
       result))
   
  -(def (class* e) function-argument-form (named-walked-form)
  +(def (class* ea) function-argument-form (named-walked-form)
     ())
   
   (def print-object function-argument-form
     (format t "~S" (name-of -self-)))
   
  -(def (class* e) required-function-argument-form (function-argument-form)
  +(def (class* ea) required-function-argument-form (function-argument-form)
     ())
   
   (def unwalker required-function-argument-form (name)
     name)
   
  -(def (class* e) specialized-function-argument-form (required-function-argument-form)
  +(def (class* ea) specialized-function-argument-form (required-function-argument-form)
     ((specializer)))
   
   (def function walk-specialized-argument (form parent env)
  
positive.code:                  (list (unwalk-form form))))
              arguments)))
  
  (def (class* e) auxiliary-function-argument-form (function-argument-form)
    ((default-value nil)))
  
  (defun walk-auxiliary-argument (form parent env)
    (destructuring-bind (name &optional (default-value nil default-value-supplied?))
        (ensure-list form)
      (with-form-object (arg 'auxiliary-function-argument-form parent :name name)
        (when default-value-supplied?
          (setf (default-value-of arg) (walk-form default-value :parent arg :environment env))))))
  
  (def unwalker auxiliary-function-argument-form (name supplied-p-parameter)
    (bind ((default-value (awhen (default-value-of -form-)
                            (recurse it))))
      (cond ((and name default-value)
             `(,name ,default-value))
            (name name)
            (t (error "Invalid auxiliary argument")))))
  
  ;;;; FLET/LABELS
  
  (def (class* e) function-binding-form (walked-form
  
negative.code: 
  (def unwalker rest-function-argument-form (name)
    name)
  
  (def (class* e) auxiliary-function-argument-form (function-argument-form-with-default-value)
    ())
  
  (defun walk-auxiliary-argument (form parent env)
    (destructuring-bind (name &optional (default-value nil default-value-supplied?))
        (ensure-list form)
      (with-form-object (arg 'auxiliary-function-argument-form parent :name name)
        (when default-value-supplied?
          (setf (default-value-of arg) (walk-form default-value :parent arg :environment env))))))
  
  (def unwalker auxiliary-function-argument-form (name supplied-p-parameter)
    (bind ((default-value (awhen (default-value-of -form-)
                            (recurse it))))
      (cond ((and name default-value)
             `(,name ,default-value))
            (name name)
            (t (error "Invalid auxiliary argument")))))
  
  (def (function e) unwalk-ordinary-lambda-list (arguments)
    (bind ((optional-seen? nil)
  