I was only looking at the external application/user perspective.  The  
number of separate steps that users need to manually configure in their  
own code tends to have a strong impact on usability; more configuration  
steps means a greater barrier to entry.  The number of steps that the  
processing itself applies internally and transparently to the user is not  
in itself significant (although the time/memory of requirements may  
sometimes be significant).

Cheers, Tony.

On Thu, 09 Aug 2007 12:51:30 +0100, Michael Kay <mike@s...> wrote:

>> Perhaps the expression "single step" was misleading, as what
>> I meant was that the validation of the input against a W3C
>> XML Schema can be done during the XSLT/XQuery processing
>> using a Schema-aware processor, so that you reduce the number
>> of individual steps in the validation process by one.
>
> If you ask Saxon-SA to validate an input document to a transformation,  
> then
> you get a push pipeline that feeds events from the XML parser through the
> schema validator to the Saxon tree builder. Apart from the crucial fact  
> that
> the type information generated by the validator is retained by the tree
> builder, this is very similar to what you would get if you put together  
> your
> own SAX-based pipeline in JAXP or XProc, which you can do of course  
> without
> a schema-aware XSLT processor.
>
> So it all depends what you mean by "steps" - separate steps from the
> application perspective, or separate steps within the internal pipeline?
>
> Internally, Saxon's input pipeline is typically much more complicated, it
> can involve steps that strip whitespace, that combine adjacent text  
> nodes,
> that expand XInclude, that locate the subtree rooted at a particular ID
> value, that maintain the namespace context, etc. And the "step" in this
> pipeline that does schema validation is itself a push pipeline whose
> internal complexity is a wonder to behold...
>
> Michael Kay
>



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Anthony B. Coates
Senior Partner
Miley Watts LLP
Experts In Data
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