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## Re: [Axiom-developer] Re: converting sexps to XML

 From: michel . lavaud Subject: Re: [Axiom-developer] Re: converting sexps to XML Date: Thu, 30 Jun 2005 03:31:41 +0200

```Hello Bob,

On 29 Jun 2005 at 12:25, Bob McElrath wrote:

> designed to do.  Since tex is a programming language I'm sure there is
> some combination of macros I could define in the preamble which would
> totally break enforcing your DOM.

Well, I'm not so sure, because TeX itself is used in the compilation, so any
correct
set of macros in the preamble is treated correctly (cf. the example proposed by
Ralf
yesterday). One exception I can think of is a change of definition inside the
text, not
in the preamble. This is the only "requirement" I can think of to ensure that,
in all
cases, partial compilation will provide the same result as complete compilation.
Automatic numberings are also incorrect, but their exact values are irrelevant
in the
tuning process.

> On the other hand, XML is *not* a programming language, it is solely a
> data structure.  This conforms to the "principle of least power":

> TeX, lisp, and sexps are all turing-complete languages.  Therefore it
> is always possible to do *anything at all* in them.

Yes I agree that they can do anything at all. I would add that, as for TeX, I
wonder if
the possibilities offered by TeX, in particular by changing the catcode of
characters
and making use of \specials, are not underestimated ? Indeed, although \$AB\$
means AB by default, it could also mean anything else, for example "Bring coffee
then Add sugar in coffee", and be interpreted as such by the dvi viewer, if we
design
it to drive a coffee machine :-) or, more difficult, it could contain (in AB)
and treat (in
the dvi driver) a whole sequence of XML tags ;-)

http://www.univ-orleans.fr/EXT/ASTEX
ftp://ftp.univ-orleans.fr/pub/tex/PC/AsTeX