References: <00e701cf7542$114f8870$33ee9950$@post.harvard.edu>           
            <537DA7E9.7080403@morningstar2.co.uk>           
            <010801cf759c$84533fb0$8cf9bf10$@post.harvard.edu> 
            <CANQYN6xxUNg9VC3O8A4n8ZA-o2K=dR0npwECnkg10rr8R+JC5Q@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Thread-Index: AQIxL1g7aqegxfBTqmzE8f5eX9UbvQHhPKs1Aa6HUTkCi8e0N5pkBc4Q
Content-Language: en-us
Content-Transfer-Encoding: 8bit
Message-ID:  <005601cf7ba0$a548cff0$efda6fd0$@gmail.com>
Date:         Thu, 29 May 2014 20:46:50 -0400
Reply-To: Mailing list for the LaTeX3 project
              <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
Sender: Mailing list for the LaTeX3 project <LATEX-L@LISTSERV.UNI-HEIDELBERG.DE>
From: Jura Pintar <jura.pintar@GMAIL.COM>
Subject: Re: Trouble with the .bool_set:N property
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <CANQYN6xxUNg9VC3O8A4n8ZA-o2K=dR0npwECnkg10rr8R+JC5Q@mail.gmail.com>
Precedence: list
Envelope-To: <rainer.schoepf@GMX.NET>
Status: R

> Wait, how is that not covered by .bool_set:N and .bool_set_inverse:N?
> Doing " turnfooingon .bool_set:N = \l_mymodule_fooing_bool " and "
> turnfooingoff .bool_set_inverse:N = \l_mymodule_fooing_bool " allows the
> user to use the keys turnfooingon and turnfooingoff as you describe.  Well, it
> also allows the user to do weirder things like "turnfooingoff=false" to turn
> fooing on.
> 
> Bruno

You're totally right: it is. I think I let my mind wander a bit when I was 
writing the example... What's actually at issue is whether constructions 
along the lines of
    
    \mymoduledoclevelsetup{ fooing = activate }
    \mymoduledoclevelsetup{ fooing = deactivate }

should be tacitly encouraged by making

    \keys_define:nn { mymodule }
     {
        fooing              .choice: ,
        fooing/ activate    .bool_set_true:N  = \l_mymodule_fooing_bool ,
        fooing / deactivate .bool_set_false:N = \l_mymodule_fooing_bool
     }

available out of the box, or whether it's better to leave it to package 
authors to use .code:n or some such alternative if they want to get 
this behaviour.

Best,

Jura