Mixed Content Models (PART II)

Jerome McDonough jmcdonou at library.berkeley.edu
Mon Sep 21 21:02:04 BST 1998

[Apologies for the earlier, partial message.  Fingers thought emacs
when I was actually in Eudora.]

Hello all,

	In looking over the XML spec (3.2.2) on mixed content
models, something isn't clear to me.  I'm hoping someone
here can enlighten me.

	I've inherited a DTD for development that was originally
intended to be an SGML DTD, and has been converted to XML.
Contained within it is the following:

	<!ELEMENT qstn   (#PCDATA | (preQTxt?, qstnLit?, postQTxt?, forward?,
							  backward?, ivuInstr*))*

Is this a legitimate content model under XML section 3.2.2?
Msxml doesn't have a problem with it, and nsgmls using the -wxml flag
also happily parses the DTD.  IBM's xml4j, however, complains:
"Codebook.dtd: 1256, 33: This content model is not matched with the
mixed model '(#PCDATA|FOO|BAR|. . .|BAZ)*': '(#PCDATA|(preQTxt?, qstnLit?,

I suppose this boils down to, should the parser ignore what's within
a content group when evaluating whether someone is trying to constrain
the order or number of occurrences of 'child elements.'  If the
only 'child elements' to be considered in the above case are:

	A.	#PCDATA, and
	B.   (preQTxt?, qstnLit?, postQTxt?, forward?, backward?, ivuInstr*)

then the above content model simplies to (A | B)* and doesn't appear
to conflict with section 3.2.2.  If 'child elements' is interpreted
as meaning *any* element contained within the content model, however,
then actually the content model doesn't look valid to me.  But if
'child elements' means any element, even those within a group, then
my content model is probably bogus.  Can someone tell me which
is the correct interpretation?

Jerome McDonough -- jmcdonou at library.Berkeley.EDU  |  (......)
Library Systems Office, 386 Doe, U.C. Berkeley     |  \ *  * /
Berkeley, CA 94720-6000    (510) 643-2058          |  \  <>  /
"Well, it looks easy enough...."                   |   \ -- /  SGNORMPF!!!
         -- From the Famous Last Words file        |    ||||

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