xml-dev - Array content model

[John.OSullivan@chase.com]

I am part of the FpML (www.fpml.org) Architecture Working Group
tasked with developing a new basic content model for FpML. My
group has been debating how to express arrays or lists in FpML.
In the first example of a list or array in the Schema primer
(http://www.w3.org/TR/xmlschema-0/) we have a list of two
instances of item, bracketed by in items tags...

<?xml version="1.0"?>
<purchaseOrder orderDate="1999-10-20">
    <shipTo country="US">
        <!-- detail elided -->
    </shipTo>
    <billTo country="US">
        <!-- detail elided -->
    </billTo>
    <comment>Hurry, my lawn is going wild!</comment>
    <items>
        <item partNum="872-AA">
            <!-- detail elided -->
        </item>
        <item partNum="926-AA">
            <!-- detail elided -->
        </item>
    </items>
</purchaseOrder>

Opinion in our working group is in favour of dropping the items tags
in our content model, and embedding the instances of item directly
in the parent element, purchaseOrder, yielding...

<?xml version="1.0"?>
<purchaseOrder orderDate="1999-10-20">
    <shipTo country="US">
        <!-- detail elided -->
    </shipTo>
    <billTo country="US">
        <!-- detail elided -->
    </billTo>
    <comment>Hurry, my lawn is going wild!</comment>
    <item partNum="872-AA">
        <!-- detail elided -->
    </item>
    <item partNum="926-AA">
        <!-- detail elided -->
    </item>
</purchaseOrder>

I favour the former arrangement, with the instances of item contained
within an items element. I prefer it since it is easier to implement
generic marshalling code on top of a DOM or SAX parser when
the SAX parser will effectively give "start array" and "end array" callbacks
for the items open and close tags. And a DOM parser will yield an items
node that is a parent for the array elements, partitioning them from
the other children of purchaseOrder.

However, my colleagues are unmoved by the ease of implementation
argument, and prefer the gain in brevity from omiting the items tags.

I'd be very grateful for any comment and argument for or against
either of these positions from xml-devers. Especially with regard
to the implications of schemas.

Cheers
John

The comments and statements expressed are not necessarily those of the
Chase Manhattan Corporation, or of its direct or indirect subsidiaries



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