Re: [xml-dev] XML design of ((a and b) or c)

["Ken North" <kennorth@sbcglobal.net>]

> The order of processing of elements in XML is therefore important if XML is to
> be used to represent computing structures as opposed to mathematical
> structures.

In the document-processing context, it's important to preserve order. However, 
an XML-based programming language is describing flow, not content. So it's a 
question of whether to assume document semantics map into the semantics of a 
programming language.

The treatment of logical operators seems germane to an discussion in this 
context. There are declarative XML languages (XUL, XAML), but XML is also the 
basis for procedural languages, such as Water, BPEL4WS and o:XML.

We've established precedents for handling logical operators with other
languages, and have seen that compiler optimization can affect the order of
processing.

If we're using an XML-based language to specify a process flow, there might be a 
similar optimization process. The process might retrieve a document fragment 
from one source, aggregate data from web services and so on. Network latency 
will enter into the optimization process.

Parallel processing and distributed data introduce issues we don't see with 
processing a document on a local hard disk. It's not clear document semantics 
should govern the process unless the end product is a document.





























======== Ken North ===========
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