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RE: A bad idea to use the XML Schema list type?

• From: "Michael Kay" <mike@s...>
• To: "'Costello, Roger L.'" <costello@m...>,<xml-dev@l...>
• Date: Mon, 9 Feb 2009 15:25:13 -0000

> 
> There are, however, significant differences with regard to 
> processing. For example, consider the task of summing all the 
> values in the list. With appproach #2 it is easily 
> accomplished using this XSLT:
> 
>     sum(li)
> 
> With approach #1 it is not easily accomplished. With XSLT 1.0 
> it requires creating a named template that splits the string 
> "89 12 41 66 2 26" and then sums the individual tokens. Not 
> an easy task. XSLT 2.0 makes the job a bit easier, but it's 
> still not as easy as with approach #2.

It's just as easy. In a schema-aware stylesheet, given the input <list>1 2
3</list>, sum(list) returns 6.

Of course, using child elements is better from a purist point of view. But
if you look at how SVG or GML represent polygons, doing it with child
elements would give a horrendous explosion of document size and parsing
time.

(However, the micro-syntax that SVG and GML use isn't XSD list syntax,
because they are dealing with a sequence of pairs of numbers. So you can't
take advantage of schema-awareness in XSLT in quite the same way; to process
these vocabularies you do have to parse the data at application level. But
that can be done very easily, you only have to write the function library to
handle the syntax once.)

Michael Kay
http://www.saxonica.com/

• Follow-Ups:
  • RE: A bad idea to use the XML Schema list type?
    • From: "Rushforth, Peter" <Peter.Rushforth@N...>

• References:
  • A bad idea to use the XML Schema list type?
    • From: "Costello, Roger L." <costello@m...>