User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:7.0.1)
            Gecko/20110929 Thunderbird/7.0.1
MIME-Version: 1.0
References: <4E95A9C2.6020607@residenset.net>           
            <4E95C086.7060806@morningstar2.co.uk>           
            <CANQYN6yk7B1Vuv+KMp6YdRt768-SHzqwNEsptO-9toVrnx+5dQ@mail.gmail.com> <4E96F7BF.9070700@residenset.net>     
            <CANQYN6x2jV8b1WPre4U0G3wq0aKc7zLUka7vD6rJWKNMMapEJg@mail.gmail.com> <4E97EA81.6040504@morningstar2.co.uk> 
            <CANQYN6xMzj_NPWzK9iM2Pkk9=OnjRpoqJ-djvq1x0MU1AHvTpQ@mail.gmail.com>           
            <4E99D8B9.6080302@morningstar2.co.uk>
            <CANQYN6z6z+vQ+MnZW8bMtzpsdkKfO0TujkpJXk9-xkw+Y4FB-w@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Message-ID:  <4E9ADB9D.6030608@morningstar2.co.uk>
Date:         Sun, 16 Oct 2011 14:26:53 +0100
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: Joseph Wright <joseph.wright@MORNINGSTAR2.CO.UK>
Subject: Re: Church booleans
To: LATEX-L@listserv.uni-heidelberg.de
In-Reply-To:  <CANQYN6z6z+vQ+MnZW8bMtzpsdkKfO0TujkpJXk9-xkw+Y4FB-w@mail.gmail.com>
Precedence: list
Status: R

On 16/10/2011 02:55, Bruno Le Floch wrote:
> I've been trying to make the change. The end-user interface is not
> changed, but since booleans become weird beasts (rather than the
> simple 0/1 switch), they are pretty much impossible to manipulate
> before the machinery is setup. The problem is then that expl3 and
> l3bootstrap need to manipulate \l_expl_status_bool very early on. I
> haven't found a clean way to resolve this issue yet, so I'm a bit
> stuck.

This should be doable. The reason for the somewhat complex set up in
l3bootstrap is that I was aiming for functions which will be defined in
a way consistent with the later code. I'm sure this can be done even if
there is a change of approach: it's just a question of being inventive :-)

> At the end of the day, Church booleans have a definite practical
> advantage, with non-expandable conditionals in \bool_if:nTF. I'm
> starting to dislike them, though, from an aestetic point of view,
> because \char"1 looks nicer than "\marker { \use_i:nn }" (with
> braces).

Yes, that slightly bothers me too. However, it's not like most people
need to worry about this most of the time.
--
Joseph Wright