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Re: Namespace of builtin functions

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Sat, 10 Jun 2006 18:59:56 +0100
Message-ID: <448B089C.20308@hp.com>
To: Howard Katz <howardk@fatdog.com>
Cc: 'Steve Harris' <steve.harris@garlik.com>, 'dawg mailing list' <public-rdf-dawg@w3.org>



Howard Katz wrote:
> Hi Andy et al. Contrary to popular rumour (or opinion), I am alive. :-)

Hoorah!

> 
> Just to point out two pieces of text from the F&O doc [1] that are relevant
> but (to me at any rate) confusing:
> 
> "The namespace prefix used in this document for functions that are available
> to users is fn. Operator functions are named with the prefix op."
> 
> and shortly thereafter:
> 
> "The functions defined with an fn prefix are callable by the user. Functions
> defined with the op prefix are described here to underpin the definitions of
> the operators in [XML Path Language (XPath) 2.0], [XQuery 1.0: An XML Query
> Language] and [XSL Transformations (XSLT) Version 2.0]. These functions are
> not available directly to users, and there is no requirement that
> implementations should actually provide these functions. For this reason, no
> namespace is associated with the op prefix."
> 
> In other words, there is an op: prefix but no namespace for it. I'm not sure
> what to make of this. 

Some much text to choose from :-)

The "no requirement" clause does not preclude providing them and the earlier 
text would give the URI.  It's also almost as if there is a shadow fn:add for 
op:add.

	Andy

> 
> Howard
> 
> [1]
> http://www.w3.org/TR/2005/WD-xpath-functions-20050915/#namespace-prefixes
> 
> 
>  > -----Original Message-----
>  > From: public-rdf-dawg-request@w3.org 
>  > [mailto:public-rdf-dawg-request@w3.org] On Behalf Of Seaborne, Andy
>  > Sent: June 10, 2006 9:17 AM
>  > To: Steve Harris
>  > Cc: dawg mailing list
>  > Subject: Re: Namespace of builtin functions
>  > 
>  > 
>  > 
>  > 
>  > Steve Harris wrote:
>  > > 
>  > > On 6 Jun 2006, at 09:54, Seaborne, Andy wrote:
>  > > 
>  > >>
>  > >>
>  > >> Steve Harris wrote:
>  > >>> Is it correct that there's no equivalent URI for the 
>  > qname looking  
>  > >>> XPath functions, such as 
>  > http://www.w3.org/TR/xpath-functions/#func- 
>  > >>> dateTime-less-than ?
>  > >>
>  > >> A couple of problems:
>  > >>
>  > >> 1/ It's "op:dateTime-less-than" and op: isn't given a 
>  > namespace URI.
>  > > 
>  > > Oops :)
>  > 
>  > Rereading the F&O namepace document:
>  > http://www.w3.org/2005/xpath-functions/#fo-summary
>  > 
>  > """
>  > Each function and operator is uniquely identified with a URI 
>  > of the form: 
>  > "http://www.w3.org/2005/xpath-functions/#name" where name is 
>  > the name of a 
>  > function or operator, such as "max": 
>  > http://www.w3.org/2005/xpath-functions/#max.
>  > """
>  > 
>  > which I read as saying there is a URI for op: named 
>  > operations, namely:
>  > 
>  > http://www.w3.org/2005/xpath-functions#dateTime-less-than
>  > 
>  > (after applying the bug report).
>  > 
>  > 	Andy
>  > 
>  > 
> 
Received on Saturday, 10 June 2006 18:00:17 GMT

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