xml-dev - Re: XML Schema?

[ht@cogsci.ed.ac.uk (Henry S. Thompson)]

Rick JELLIFFE <ricko@geotempo.com> writes:

> [Various points comparing XML Schema to DTD, only some of which I
>  comment on below]

>  2) type is directly keyed from the element name (or an xsi:type
> attribute), which does not allow the user-friendly markup idiom of where
> the element name gives the basic type of the element and an attribute
> declares the subtype; instead, if one wants subtyping, one has to make
> an explicit new element named for that--one must have <textInput> rather
> than <input type="text">...

This is misleading at best: This style of document is somewhat
_better_ supported by XML Schema than it is by DTDs -- you can
perfectly well write <input type="text">...</input> in a schema-valid
document, and in some cases you can even organise things so that the
content validated thereunder is validated differently to e.g. the
content of <input type="hamAndEggs">...</input>.

>   6) XML Schemas is namespace based, so if you do not use namespaces you
> cannot use XML Schemas (last time I checked...hmmm don't quote me, I
> have to check the status quo and my shocking memory confuses me easily)

False.  Writing an XML Schema for documents with no namespace
declaration is no different from writing one for documents with
namespaces, it just takes fewer keystrokes (since you don't have to
specify the namespace the schema is for).

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/

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