Re: Types for Option Values

Alex Milowski wrote:
> It would certainly be nice for the p:option to have some declaration
> of the type value to assist tools in authoring option values or debugging
> pipelines.
> 
> A simple proposal would be to allow an optional 'type' attribute on
> p:option element that has a QName value.   That identifies a type name
> that may or may not be known by a pipeline processor.

I'd really rather not do this (in v1 at least). Options should have 
string value and nothing else. The main reason is that in v1 we're using 
XPath 1.0 and XPath 1.0 doesn't know anything about types aside from 
string, number and boolean. For example, if I had:

   <p:option name="element-name" type="xs:QName" value="my:foo" />

then I, as a pipeline author, might reasonably expect the value to be 
passed *as*a*QName* and therefore to be able to extract the namespace 
URI and local name from it in the implementation of the called pipeline. 
But those facilities aren't available in XPath 1.0: I have to process 
the option value as a string.

I suppose we *could* say that the type attribute purely constrained the 
lexical representation of the value, and the value itself is a string, 
but I do think this would cause confusion.

Cheers,

Jeni
-- 
Jeni Tennison
http://www.jenitennison.com

Received on Wednesday, 23 May 2007 08:12:28 UTC