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Date:         Thu, 2 Oct 2014 15:36:51 +0200
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From: =?utf-8?Q?Denis_Bitouz=C3=A9?=
              <denis.bitouze@LMPA.UNIV-LITTORAL.FR>
Subject: Re: [l3keys] Suggestion: Add a key property for specifying key that /has/ to be used
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <542C1972.5030500@morningstar2.co.uk> (Joseph Wright's message of
              "Wed, 1 Oct 2014 17:10:42 +0200")
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Le 01/10/14 à 17h10, Joseph Wright <joseph.wright-NisN+YXOI8VaA8anhhA8LJ6WHSJbwjtC@public.gmane.org> a écrit :

> On 30/09/2014 19:00, Denis Bitouzé wrote:
>>> At present, key properties mainly apply to individual keys in a 'stand
>>> alone' sense. This request is different as it's actually about an entire
>>> set of keys.
>> 
>> No, maybe I was unclear: my question concerned the "requireness" of
>> a single (or maybe several but treated separately) key property.
>
> On the other hand, a requirement to set some key can only be tested at
> the end of \keys_set:nn, once you know what keys were set. Moreover,
> it's potentially ambiguous as
>
>   \keys_set:nn { foo } { required = value }
>   \keys_set:nn { foo } { other-key }
>
> doesn't have the "required" key in the second setting: is it required
> here or not?

Maybe that's a nonsense idea, but couldn't it be possible to check the
key has been used \AtEndDocument?
-- 
Denis