external functions: prior art in Qexo

Various issues (possibly 124 157 223 272 317) discuss the need
for being able to call "external functions".  This page:
http://www.gnu.org/software/qexo/Extensions.html#Calling-Java-Methods
explains how Qexo allows XQuery functions to call arbitrary Java
methods.  Of course this mechanism is too Java-specific to be 
standardized (though similar mechanisms should work for other
languages).  However, possibly Java implementors come agree some
something that could be a non-normative addendum.

The mechanism in issue 223 is more general and robust, as it
allows extenrnal functions to be defined in any language,
including XQuery and Java.  However, it still leaves open how
to bind an external function to a (say Java) method.

(I make no claim for originality - XSLT implementations have used
similar extension mechanisms for years.)
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/per/

Received on Tuesday, 14 January 2003 23:11:18 UTC