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[Bug 4231] K2-Literals-7

From: <bugzilla@wiggum.w3.org>
Date: Tue, 16 Jan 2007 10:02:27 +0000
CC:
To: public-qt-comments@w3.org
Message-Id: <E1H6l99-0002CR-6L@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=4231

           Summary: K2-Literals-7
           Product: XML Query Test Suite
           Version: unspecified
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: XML Query Test Suite
        AssignedTo: andrew.eisenberg@us.ibm.com
        ReportedBy: tim@cbcl.co.uk
         QAContact: public-qt-comments@w3.org


This test aims to catch underflow in xs:decimal with an expected result of 0.0.

Underflow is defined in:

http://www2.hursley.ibm.com/decimal/daexcep.html

as:

"This occurs and signals underflow if a result is inexact and the adjusted
exponent of the result would be smaller (more negative) than the smallest value
that can be handled by the implementation (the value Emin). That is, the result
is both inexact and subnormal."

If I understand this correctly, underflow will occur for numbers very close to
zero, not numbers which are large negative values.

Therefore a suitable number for this test might be:

0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001

Note also that due to the EBNF for decimal literals:

142] DecimalLiteral ::= ("." Digits) | (Digits "." [0-9]*)

this parses as:

-(9999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999.1)

i.e. operator unary minus applied to a large (possibly overflowing) decimal.

(:*******************************************************:)
(: Test: K2-Literals-7                                   :)
(: Written by: Frans Englich                             :)
(: Date: 2007-01-12T16:19:57+01:00                       :)
(: Purpose: Use a relatively small xs:decimal literal.   :)
(:*******************************************************:)
-9999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999.1
Received on Tuesday, 16 January 2007 10:02:38 UTC

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