Re: [xml-dev] Recommended way to extend Schematron?

[Jim Melton <jim.melton@oracle.com>]

Roger,

Being only slightly snarky (in my first 
suggestion), I can suggest three possibilities that may be worth consideration:

1) XQuery 1.0 is computationally complete and can 
be used to write functions that perform those 
calculations; under several implementations, it 
is possible to invoke those functions from XPath 2.0 expressions.

2) XPath 3.0 ("Coming Soon to a Theater Near 
You™") has those particular functions built in, 
as well as even more mechanisms for defining them 
natively; there are several implementations of 
XPath 3.0 (and XQuery 3.0), even though we're 
still at the tail-end of the Candidate Recommendation stage.

3) EXPath is a community effort that has defined 
a number of useful functions to be invoked (using 
a different namespace than the standardized "fn:" 
namespace) from XPath; many XPath 2.0 
implementations recognize that namespace.

Hope this helps,
    Jim


At 5/7/2013 12:02 PM, Costello, Roger L. wrote:
>Hi Folks,
>
>Suppose my Schematron assertions need to do some 
>math calculations – cosine, sine, tangent, etc.
>
>I am using XPath 2.0 in my Schematron 
>assertions. But XPath 2.0 doesn’t support 
>functions for cosine, sine, tangent, etc.
>
>What is the recommended way to extend Schematron?
>
>/Roger

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Jim Melton --- Editor of ISO/IEC 9075-* (SQL)     Phone: +1.801.942.0144
   Chair, ISO/IEC JTC1/SC32 and W3C XML Query WG    Fax : +1.801.942.3345
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