- From: Kirmse, Daniel <daniel.kirmse@sap.com>
- Date: Thu, 15 Apr 2004 10:38:12 +0200
- To: "'www-ql@w3.org'" <www-ql@w3.org>
- Message-ID: <5A82701DD88A984E871D691ED6B19ACD307EBD@dewdfe12.wdf.sap.corp>
Hi, I have a question to the formal semantics of the general comparison. In http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/#sec_general_comparisons <http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/#sec_general_comparisons> it is described as follows: [Expr1 GeneralOp Expr2]Expr == some $v1 in fn:data([Expr1]Expr) satisfies some $v2 in fn:data([Expr2]Expr) satisfies let $u1 := fs:convert-operand($v1, $v2) return let $u2 := fs:convert-operand($v2, $v1) return [GeneralOp]GeneralOp ($u1, $u2) assuming Expr1 and Expr2 being sequences, there is a nested loop like this: for all elements in Expr1 for all elements in Expr 2 let $u1 := fs:convert-operand($v1, $v2) return let $u2 := fs:convert-operand($v2, $v1) return GeneralOp ($u1, $u2) As described, $v1 will be converted to the type of $v2 or string depending on the type of $v2. And then $v2 will be converted to the type of $v2??? Does this make any sense at all? Or should it rather be $v2 is converted to the type of $u1? In case of $v2 has type not equal xdt:untypedAtomic $u1 has the same type as $v2 and in the other case $u1 has type string and converting $v1 with $expected = type($u2) = xdt:string would yield $u2 having type string as well. Am I right in assuming the correct equation to be: [Expr1 GeneralOp Expr2]Expr == some $v1 in fn:data([Expr1]Expr) satisfies some $v2 in fn:data([Expr2]Expr) satisfies let $u1 := fs:convert-operand($v1, $v2) return let $u2 := fs:convert-operand($v2, $u1) return [GeneralOp]GeneralOp ($u1, $u2) or am I just plain wrong? Dealing with the same issue: Considering function fs:convert-operand as described in http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/#sec_convert_operand <http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/> . When having statEnv <http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/> .xpath1.0_compatibility <http://www.w3.org/TR/2004/WD-xquery-semantics-20040220/> = false, type($actual) = String and type($expected) = Integer no conversion is done, right? Considering a general comparison of a string and an integer value. According to the formal semantics of the general comparison, convert-operand would be called for both values but no conversion would take place actually. So I end up with a comparison of a string and an integer that is not defined (no overloaded comparison function exists taken these two types). That would force me to throw a XP0004 or XP0006 error due top the incompatible types, right? Thanks & Cheers Daniel
Received on Thursday, 15 April 2004 04:39:15 UTC