Re: [xsl] W3C Specification of fn:filter() -- is this a bug in the document or in Saxon?

["Liam R. E. Quin liam@xxxxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

On Mon, 2019-09-09 at 00:18 +0000, Dimitre Novatchev
dnovatchev@xxxxxxxxx wrote:
> The W3C F&O 3.1 spec (at
> https://www.w3.org/TR/xpath-functions-31/#func-filter ) says:
> 
> Rules
> 
> The effect of the function is equivalent to the following 
[...]
> 
> Because "equivalent" means the two functions must produce the same
> result
> for for all possible values in the same set of arguments, 

That is one possible definition of "equivalent" but it is not the one
used in the Functions and Operators document...

You can never guarantee that two expressions are equivalent in your
sense, because of "errors and optimization". Any construct might raise
an error - in the case of this example, stack overflow if the recursion
gets too deep.

Liam

-- 
Liam Quin, https://www.delightfulcomputing.com/
Available for XML/Document/Information Architecture/XSLT/
XSL/XQuery/Web/Text Processing/A11Y training, work & consulting.
Carefoot Web-slave for historical images http://www.fromoldbooks.org/