Re: Suggestions for handling XML from Kawa?

[Per Bothner <per at bothner dot com>]

Jocelyn Paine <popx@pop3.ifs.org.uk> writes:

> To take my last message (about TreeList) further, has anyone any
> suggestions on the best way of processing parsed XML from Kawa?

I like the idea of using pattern matching combined with
"xml type expressions".  XQuery has a type algebra that is rather
expressive.  You can combine this with run-time type tests.and
"FLWR"-expressions to do some quite fancy stuff.  Even nicer
would be ML-style patterns where you can make variable bindings to
*parts* of a value.  A hypothetical Scheme syntax might be:

(match EXPR
  ((x :: (element-type 'a)) => (something1 x))
  ((element-type 'b (y :: (element-type 'c))) => (something2 y))
  (else => (something3)))

This would evaluate EXPR and first see if it is <a>...</a>.
If so, the variable x is bound to the element, and someting1 is called.
Otherwise, we see is teh value of EXPR matches <a><c>...</c?</b>.
If so, y is bound to the <c>...</c>, and something2 is called.
Otherwise, something3 is called.

I suggest reading about XQueryand related issues at
http://www.w3c.org/XML/Query.  There are some interesting ideas there.
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/per/