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RE: seq-some-p and nil

From: Nicolas Petton
Subject: RE: seq-some-p and nil
Date: Wed, 09 Sep 2015 23:44:27 +0200
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Drew Adams <address@hidden> writes:

>> I meant extra complexity for the user.  If seq-some was returning a
>> value, I wouldn't expect it to be a cons cell, I'd almost always want
>> the element of the sequence straight away.
> Well, yes.  But what if the user wants the value returned by the
> function?

`seq-some', as it is now defined, is the right function to use.

> And what if the element is nil?

Then maybe seq-find is not the right function to use.  Or seq-find
could, as Stephen suggested, take an optional sentinel argument for
these very rare cases.

I know that your suggestion also fixes the semantic issue, but I don't
like the cost it adds.  99% of the times, you will want the element you
searched for in the seq.  I think using seq-find should remain simple
and straightforward, just like `find-if' in CL.  I also had another look
at the Clojure and Scheme equivalents, and they both have a similar
corner case, though in the case of Clojure, `true' is returned instead
of `nil'.


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