Appendix K.1.2 is not completely accurate here. If you look at the normative text under xsl:number, you will see that the error condition is ERR XT0980, which is defined as a recoverable error. Saxon issues a warning for conditions described in the specification as recoverable errors. I will fix the appendix (I have editorial discretion to do this as it is non-normative).
Michael Kay

From: [] On Behalf Of Alexander Shrago
Sent: 11 May 2004 14:20
Cc: Alexander Makanin
Subject: [saxon] Fw: question

Hello Mr. Kay!
Please suggest  how to explain the result of my test with saxon 7 :

According to XSL Transformations (XSLT) Version 2.0 (W3C Working Draft 12 November 2003):

"If the xsl:number instruction was evaluated with a value attribute whose value cannot be cast to an integer, an XSLT 1.0 processor would output "NaN"; an XSLT 2.0 processor will signal an error."

I test this sample, but I receive only warning instead of error 

Best regards!