From: Artur Malabarba <bruce.connor.am@gmail.com>
To: Phillip Lord <phillip.lord@newcastle.ac.uk>
Cc: Nicolas Petton <nicolas@petton.fr>,
Emacs-Devel devel <emacs-devel@gnu.org>
Subject: Re: behaviour change in cl-subseq
Date: Fri, 21 Aug 2015 01:02:18 +0100 [thread overview]
Message-ID: <CAAdUY-J6-VCWvx2-ZAgKfzQNa54PpCONff8XbeF-a3PfZSyx2w@mail.gmail.com> (raw)
In-Reply-To: <877fopadmv.fsf@russet.org.uk>
> (defun seq-contains-p (seq elt &optional testfn)
> "Return the first element in SEQ that equals to ELT.
> Equality is defined by TESTFN if non-nil or by `equal' if nil."
> (seq-some-p (lambda (e)
> (funcall (or testfn #'equal) elt e))
> seq))
>
> Two issues. Implementation wise, you are depending on behaviour outside
> the interface of seq-some-p which says....
>
> "Return any element for which (PRED element) is non-nil in SEQ, nil
> otherwise."
>
> The other option is to add a `seq-contains-nil-p' function.
>
> Personally, I'd change seq-contains-p. Better to break the interface of
> seq-contains-p earlier rather than later.
I think both functions need to change behavior. They are named as
`-p', but "return an element" is not the behavior of a boolean
predicate (precisely because of the situation you describe).
IMO, the current behavior of `seq-some-p' should be called `seq-some'.
And the same for `seq-contains'.
next prev parent reply other threads:[~2015-08-21 0:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-05 12:14 behaviour change in cl-subseq Phillip Lord
2015-08-06 0:10 ` Leo Liu
2015-08-06 6:11 ` Tassilo Horn
2015-08-06 9:34 ` Phillip Lord
2015-08-06 9:48 ` Leo Liu
2015-08-07 14:00 ` Phillip Lord
2015-08-07 14:26 ` Nicolas Petton
2015-08-07 15:51 ` Phillip Lord
2015-08-07 16:08 ` Nicolas Petton
2015-08-07 21:23 ` Phillip Lord
2015-08-08 19:56 ` Nicolas Petton
2015-08-20 20:50 ` Phillip Lord
2015-08-21 0:02 ` Artur Malabarba [this message]
2015-08-06 8:08 ` Nicolas Petton
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