Content-Type: text/plain; charset=windows-1252
Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.2\))
References: <m2vbpt81jx.fsf@smbp.home> <m2lhqp818q.fsf@smbp.home>
            <CAHkWWc0iDjK-xOSoNoG4zLmkNaokVw5UwKmBrXQzfgvXkraPVA@mail.gmail.com> <53F667E1.8080909@morningstar2.co.uk>
            <a2dd3125f58ad369f6f7482acd8acb67.squirrel@webmail.seanallred.com>
Message-ID:  <5B8B103B-5CCD-490E-9177-F1B8F65C26BF@gmail.com>
Date:         Sun, 24 Aug 2014 11:23:25 +0930
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: Will Robertson <wspr81@GMAIL.COM>
Subject: Re: Thoughts on xtemplate
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <a2dd3125f58ad369f6f7482acd8acb67.squirrel@webmail.seanallred.com>
Precedence: list
Content-Transfer-Encoding: quoted-printable
Envelope-To: <rainer.schoepf@GMX.NET>
Status: R

On 23 Aug 2014, at 4:49 am, Sean Allred <tex@SEANALLRED.COM> wrote:

> And I don't mean to advocate that these objects should be able to have
> many (9+) mandatory arguments; I'm far more concerned with the
> homelessness for optional ones.

I think after Frank=92s experiments with sectioning, it became apparent t=
hat this was a major stumbling block. When a chapter heading can have

1. title
2. toc title
3. header title
4. label
5. unnumbered flag
6. author
7. epigraph
=85

it no longer makes sense to require mandatory arguments. On the other han=
d I do see Joseph=92s point that when you have just one or two actually m=
andatory arguments that writing the following is a bit ugly:

   \UseInstance{crossref}{latex2e}{ label =3D #1 }% only one mandatory ar=
gument

* * *

A model that I think has worked quite well in the LaTeX world is how BibT=
eX has a notion of =93mandatory=94 and =93optional=94 fields for bibliogr=
aphy references.

Perhaps we could supplement the current xtemplate interface with a keyval=
-type-argument (one only per interface, of course), in which the optional=
/mandatory nature of each keyval item within is specified by the document=
 design (and some may well be always mandatory).

So according to the situation you could have either

    \UseInstance{=85}{=85}{arg one}{arg two}{arg three}

or

    \UseInstance{=85}{=85}{ arg-one=3D=85 , arg-two=3D=85, arg-three=3D=85=
 }

or even a combination of the two:

    \UseInstance{=85}{=85}{arg one}{ arg-two=3D=85, arg-three=3D=85 }

Any thoughts?

Will