GitLab

at 2023-08-26T20:42:51-07:00

Add comments and fix docstring.

The docstring says set-exclusive-or produces elements appearing
exactly once in list1 and list2.  But that's not right.  The result
has elements appearing in either list1 or list2 but not both.  Use the
text from the CLHS as the docstring.

Add some comments to the code.

@@ -906,7 +906,7 @@
  (defun set-exclusive-or (list1 list2 &key key
                           (test #'eql testp) (test-not nil notp))
 -  "Return new list of elements appearing exactly once in LIST1 and LIST2."
 +  "Return new list of elements appearing exactly one of LIST1 and LIST2."
    (declare (inline member))
    (let ((result nil)
          (key (when key (coerce key 'function)))
@@ -914,6 +914,8 @@
          (test-not (if test-not (coerce test-not 'function) #'eql)))
      (declare (type (or function null) key)
               (type function test test-not))
 +    ;; Find the elements in list1 that do not appear in list2 and add
 +    ;; them to the result.
      (let ((hashtable (list-to-hashtable list2 key test test-not)))
        (cond
          (hashtable
@@ -924,6 +926,8 @@
           (dolist (elt list1)
             (unless (with-set-keys (member (apply-key key elt) list2))
  	     (setq result (cons elt result)))))))
 +    ;; Now find the elements in list2 that do not appear in list1 and
 +    ;; them to the result.
      (let ((hashtable (list-to-hashtable list1 key test test-not)))
        (cond
          (hashtable

Raymond Toy pushed to branch issue-240-add-hashtable-set-exclusive-or at cmucl / cmucl

Commits:

1 changed file:

Changes: