SGML Architecture questions

Dmitri Kondratiev (dima@paragraph.com)
Sun, 01 Feb 1998 03:46:32 +0300

I may be wrong, but from my understanding of SGML architecture, only
bridging mechanism provides for type extension. Everything else in
architecture seems to be element and attribute names remaping. Bridging
element serves as a target for mapping substructure to it. Still bridging
element is not defined in DTD and as a result its content/attributes can't
be validated by parser. Is that correct ?

Taking bridging example from "A Tutorial Introduction to SGML Architectures"
by W. Eliot Kimber, with architectural DTD :

<!-- Person Name and addresses architecture ("personarch")-->
<!ELEMENT person
(name,
address?)
>
<!ELEMENT name
(#PCDATA | archbridge)*
>
<!ELEMENT address
(#PCDATA | archbridge)*
>
<!ELEMENT archbridge
(#PCDATA | archbridge)*
>

And mapping from elements in the document to elements in the architecture :

<?XML version="1.0" ?>
<?IS10744:arch name="personarch"
bridge-form="archbridge"
?>
<!DOCTYPE customer.record [
<!ATTLIST customer.record personarch NAME #FIXED "person" >
<!ATTLIST cust.name personarch NAME #FIXED "name" >
<!ATTLIST last personarch NAME #FIXED "archbridge" >
<!ATTLIST first personarch NAME #FIXED "archbridge" >
<!ATTLIST cust.address personarch NAME #FIXED "address" >
<!ATTLIST street personarch NAME #FIXED "archbridge" >
<!ATTLIST city personarch NAME #FIXED "archbridge" >
<!ATTLIST state personarch NAME #FIXED "archbridge" >
<!ATTLIST zip personarch NAME #FIXED "archbridge" >
]>
<customer.record>
<cust.name><last>Kimber</last><first>William</first></cust.name>
<cust.address>
<street>1234 Maple St.</street>
<city>Austin</city><state>TX</state><zip>78757</zip>
</cust.address>
</customer.record>

There is no DTD for <archbridge> element content so:

<last>Kimber</last><first>William</first>

could be :

<last>Kimber</last><middle>Eliot</middle><first>William</first>

So my question is :
how validity constraints can be enforced for bridging element substructure ?

Thanks,
Dima

-----------------
Dmitri Kondratiev
dima@paragraph.com
102401.2457@compuserve.com
http://www.geocities.com/SiliconValley/Lakes/3767/
tel: 07-095-464-9241