RE: XQuery Updates in XSLT

> Only add complexity if the benefits 
> clearly outweighs that we need an extra tutorial or chapter 
> in a text book.
> 

There's certainly a trade-off: when you provide a new construct you have to
weigh the fact that it will be easier to write certain stylesheets against
the fact that the spec will become longer, the implementation bigger, and
the learning curve a bit longer.

I think the identity template pattern is so common, however - and it often
increases the size of a stylesheet by 200% - that it's well worth making it
easier to write. Our main motivation, though, was not to reduce the number
of lines of code that users have to write, but rather to make it easier for
optimizers to detect the pattern, which is particularly important (we
decided) as an enabler for streaming transformations.

Michael Kay
http://www.saxonica.com/