RE: Higher-Order Functions in XSLT (Was: RE: xslt 2.0 suggestion -- explicit extensions, and support for next-match)

> Let's call things with their proper names -- you're talking 
> here about a particular case of functional composition.
> 
> By now, it should have become quite clear, that support for 
> higher-order functions
> in XPath 2.0 and XSLT 2.0 is the logical and necessary 
> foundation for this and other similar proposed extensions.
> 
The proposed data model for XQuery 1.0 and XPath 2.0 (and therefore for XSLT
2.0) is published at [1]. Currently, this model does not include functions
as objects that can be manipulated within the type system, which means that
functions cannot take functions as arguments or produce functions as their
results.

If you want to argue the case for higher-order functions, I would suggest
you do it in the form of a comment on the published data model, which should
be addressed to www-xml-query-comments@w3.org

It would be best to put together the argument as a free-standing document
that doesn't rely on previous correspondence, remembering that half the
audience are more interested in XQuery than in XSLT.

The joint XPath task force has previously decided against including
higher-order functions and may well feel that this is too big a change to
make at this stage. This is partly because we already have enough of a
challenge sorting out the precise semantics of the type system without this
extra complication. However, if you put forward the case I'm sure it will be
considered on its merits.

Mike Kay


[1] http://www.w3.org/TR/query-datamodel/ 

Received on Monday, 19 November 2001 04:36:54 UTC