RE: [xml-dev] RE: Concerned about the increasing reliance on XPath

["Costello, Roger L." <costello@mitre.org>]

Hi Mike,

> What does your "assessment" step really do anyway?  You didn't say.

There are many ways that one may wish to analyze an XML instance document. For the "purchase XML instance document" we may wish to analyze it to determine:

- is the value of <Total> a decimal value (and nothing else)
- will the instance document, when evaluated, trigger unexpected and undesirable actions
- is the value of <Total> equal to the sum of its Item siblings
- perform an algebraic data type analysis

And many other types of analyses.

/Roger

-----Original Message-----
From: Michael Sokolov [mailto:sokolov@ifactory.com] 
Sent: Monday, May 09, 2011 3:38 PM
To: Costello, Roger L.
Cc: xml-dev@lists.xml.org
Subject: Re: [xml-dev] RE: Concerned about the increasing reliance on XPath


> <Purchase>
>        <Item>10.00</Item>
>        <Item>20.00</Item>
>        <Total>
>              <SumPrecedingItems>
>                   <Value>30.00</Value>
>              </SumPrecedingItems>
>        </Total>
> </Purchase>
The element probably should have been named "SumSiblingItems" to create 
a better analogy.

OK, so what - but the point is that re-inventing XPath as a series of 
named elements will lead you to an exceedingly painful syntax.  If you 
don't need the power of XPath, OK you don't need it.  But sometimes you 
do, and in such cases it doesn't make sense to try replacing it with 
something less elegant just to make the job of a syntax parser 
("assessor"?) easier.

What does your "assessment" step really do anyway?  You didn't say.

-Mike