Way off topic (was: Lisp concrete syntax)

[Rick Jelliffe]

>Not to be a pest or anything, shouldn't this be...
>
><sexp>
>    <car>+</car>
>    <cdr><car>1</car><cdr><car>1</car><cdr/></cdr></cdr>
></sexp>

There are three things we could be notating:
 * parsing the s-expression source code;
* fully expanding the notional LISP lists;
* exposing the implementation.

The form I gave parses the s-expression. The version you give shows the
fully expanded list. And if an implementation used cdr-coding, it would
look like my version; if it used explicit nulls, it would look like your
version.

This is a good example that XML markup is not a data modeling language,
but a data-model modeling language :-)  The lexical, semantic and
implementation structures of a programming language are all different,
and a XML document could reflect any of them (or even a mix).

Rick

P.S. For more on cdr-coding, refer
http://www.landfield.com/faqs/lisp-faq/part2/section-9.html



xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To (un)subscribe, mailto:majordomo at ic.ac.uk the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)