XML and embedded compound data types (was "Why XML data typin is hard")

John Cowan cowan at locke.ccil.org
Mon Nov 30 18:18:57 GMT 1998

Gabe Beged-Dov wrote:

> I have been reading the latest postings on XML data typing and want to throw
> out a different viewpoint. several caveats are that I haven't perused all of
> the archives to see if I'm tramping down well-worn paths.

Not well-worn, but not utterly novel either.

> The perspective is the possibly naive one that XML can/should be used to
> capture ALL of the structural aspects of a complex tree of data. Wherever a
> compound type occurs in the source data, it should be mapped to a
> corresponding compound type in XML.  A key heuristic to see if this approach
> is being adhered to is to see if any attribute  values or character data
> requires additional parsing by the application in order to deserialize
> additional structure.

A compromise which I proposed --- to resounding denunciation from all
(then existing) quarters --- was a facility overlaid on XML which would
remap specific local syntax characters, when found within the character
content of specified elements, to empty element tags.  Thus, given the
following XML:

	<?map map1 ":" colon?>
	<?map map1 "T" time?>
	<?map map1 "-" dash?>
	<?map map1 "." dot?>
	<?apply-map map1 date?>

the application would receive the SAX or DOM equivalent of:


This is level 1 of my "Local Markup" proposal; level 2 provides
for nested as well as empty tags generated by characters,
by allowing for prioritization of local markup characters.
Only single characters are supported, but since there are
65000 of them, that should be sufficient.

SGML had something like this, but much more powerful/flexible/
hard to parse.

John Cowan	http://www.ccil.org/~cowan		cowan at ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)

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