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bug#26540: 25.2; [PATCH] Add cl-set-equal to test for set equality


From: Damien Cassou
Subject: bug#26540: 25.2; [PATCH] Add cl-set-equal to test for set equality
Date: Tue, 18 Apr 2017 16:40:19 +0200

Drew Adams <drew.adams@oracle.com> writes:
I'm just pointing out that a function we already have, and one that is used more widely by users of Common Lisp, does the same thing - unless I'm missing something.


I agree (except that one has opposite result).

If people think that some users might not think to use `set-exclusive-or' to test set equality then we could add a `set-equal' function. Common Lisp didn't think so, and neither do I, but I wouldn't oppose adding it.


At least I didn't think about using exclusive-or. Searching for "equal" or "same elements" in the info page (info "(cl) Lists as Sets") didn't help.

If we do add it, I'd imagine that the implementation should be the same (adding `not', as you say), for clarity and consistency - unless other things are not equal for some reason (i.e., unless there is a good reason not to use the existing implementation).


I updated the patch.

--
Damien Cassou
http://damiencassou.seasidehosting.st

"Success is the ability to go from one failure to another without
losing enthusiasm." --Winston Churchill

Attachment: 0001-Add-cl-set-equal-to-test-for-set-equality.patch
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