anchor.diff:  
   (define-test test-optional-parameters
       "Optional parameters are filled in with their default value."
  -   (assert-equal (func-with-opt-params :test-1 :test-2) ___)
  -   (assert-equal (func-with-opt-params :test-1) ___)
  -   (assert-equal (func-with-opt-params) ___))
  +   (assert-equal (func-with-opt-params :test-1 :test-2) '(:test-1 :test-2))
  +   (assert-equal (func-with-opt-params :test-1) '(:test-1 3))
  +   (assert-equal (func-with-opt-params) '(2 3)))
   
   
   ;; ----
  
positive.code:     "An illustration of how lexical closures may interact."
    (let ((tangled-funs-1 (two-funs 1))
          (tangled-funs-2 (two-funs 2)))
       (assert-equal (funcall (first tangled-funs-1)) ___)
       (funcall (second tangled-funs-1) 0)
       (assert-equal (funcall (first tangled-funs-1)) ___)
  
       (assert-equal (funcall (first tangled-funs-2)) ___)
       (funcall (second tangled-funs-2) 100)
       (assert-equal (funcall (first tangled-funs-2)) ___)))
  
  
  (define-test test-apply-function-with-apply
  
negative.code:    "Common Lisp optional params may bind a symbol which indicate whether the
      value was provided or defaulted.  Each optional parameter binding has the
      form (var default-form supplied-p)."
     (assert-equal (func-with-opt-params-and-indication :test-1 :test-2) '(:test-1 t :test-2 t))
     (assert-equal (func-with-opt-params-and-indication :test-1) '(:test-1 t 3 nil))
     (assert-equal (func-with-opt-params-and-indication) '(2 nil 3 nil)))
  
  
  ;; ----
  