- From: Andrew Eisenberg <andrew.eisenberg@us.ibm.com>
- Date: Fri, 9 Apr 2004 14:59:21 -0400
- To: public-qt-comments@w3.org
- Message-ID: <OFC8CE6F00.00C6DA31-ON85256E71.00680D47-85256E71.00684F9F@us.ibm.com>
I believe that "le" and "ge" return the wrong values when NaN values are
provided for either of the two operands.
Consider the following query:
let $x := 1.0e0
let $nan := xs:double('NaN')
return
$x eq $nan, (: will return false :)
$x lt $nan, (: will return false :)
$x gt $nan, (: will return false :)
$x le $nan, (: will return true :)
$x ge $nan, (: will return true :)
$x ne $nan (: will return true :)
I believe that "le" and "ge" should return false to be consistent with
IEEE 754. They return true because:
1) The definition of op:numeric-less-than and op:numeric-greater-than in
F&O both contain the following:
"If $arg1 or $arg2 is NaN, the function returns false."
2) The Binary Operator table in XQuery, B.2 Operator Mapping, contains the
following:
A ge B numeric numeric fn:not(op:numeric-less-than(A, B))
xs:boolean
A le B numeric numeric fn:not(op:numeric-greater-than(A,
B)) xs:boolean
To effect the change I suggest, change the that two rows of the Binary
Operator table to the following:
A ge B numeric numeric op:numeric-greater-than(A,
B) or op:numeric-equal(A,B) xs:boolean
A le B numeric numeric op:numeric-less-than(A, B)
or op:numeric-equal(A,B) xs:boolean
-- Andrew
--------------------
Andrew Eisenberg
IBM
4 Technology Park Drive
Westford, MA 01886
andrew.eisenberg@us.ibm.com
Phone: 978-399-5158 Fax: 978-399-7012
Received on Friday, 9 April 2004 14:59:55 UTC