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   Re: [xml-dev] Adam Bosworth Article - what does "direct access" mean?

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On Thursday 16 January 2003 19:28, W. E. Perry wrote:

> As for 'direct
> access', it means (as it always has since I started reading code in
> 1966):  conforming exactly to brittle expectations from a priori
> agreements, so that I don't have to parse it, lex it, analyze it,
> compare it to its history, or otherwise do in computerized processing
> what the human brain has to do in handling every bit of new input it
> ever encounters. Have any of the defenders of direct access here (are
> there any?) said anything to contradict that characterization?

I'll bite :-)

I say that's a purely relative statement. Whereas in a programming language 
we have to access our XML via various ungainly constructs, in XSLT it's a lot 
simpler because XSLT's data model is the XML data model so you don't need to 
do any conversions.

However, if you have data stored in the format of a serialised Java object it 
would be nice and easy to access from Java, but from XSLT you would need to 
do something with an HTTP-accessible converter along the lines of:


The expectations some XSLT has of an XML document is just as brittle as the 
expectation some Java code might have of a Java object. My "object.field" 
will break if the field is renamed in the same way that "/root/field" would. 

It's not about whether parsing happens or not - calling stream.readObject () 
in Java invokes a kind of parser to deserialise the object; the difference is 
in data model conversion. XML is a data model that the language XSLT is based 
around, while Java is based around a different one, so mapping from one to 
the other involves a bit more work.

> Walter Perry


A city is like a large, complex, rabbit
 - ARP


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