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comment on current deliberations in RDF Core concerning the lexical space of XML Schema datatypes

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 12 Sep 2003 04:08:39 -0400 (EDT)
Message-Id: <20030912.040839.08243579.pfps@research.bell-labs.com>
To: www-rdf-comments@w3.org

I see several claims in the RDF Core WG mailing list archives to the effect
that the lexical space of XML Schema datatypes is not well-defined.
However, when I look at http://www.w3.org/TR/xmlschema-2/, I see very
specific definitions of the value space of XML Schema datatypes.  For
example http://www.w3.org/TR/xmlschema-2/#decimal states 

	3.2.3.1 Lexical representation

	decimal has a lexical representation consisting of a finite-length
	sequence of decimal digits (#x30-#x39) separated by a period as a
	decimal indicator. If totalDigits is specified, the number of
	digits must be less than or equal to totalDigits. If
	fractionDigits is specified, the number of digits following
	the decimal point must be less than or equal to the
	fractionDigits. An optional leading sign is allowed. If
	the sign is omitted, "+" is assumed. Leading and trailing zeroes
	are optional. If the fractional part is zero, the period and
	following zero(es) can be omitted. For example: -1.23,
	12678967.543233, +100000.00, 210.

This appears to me to be completely well-defined.  In particular, leading
and trailing spaces are *NOT* allowed in the lexical representation of the
XML schema decimal datatype.

Also, http://www.w3.org/TR/xmlschema-2/#integer states 

	3.3.13.1 Lexical representation

	integer has a lexical representation consisting of a finite-length
	sequence of decimal digits (#x30-#x39) with an optional leading
	sign. If the sign is omitted, "+" is assumed. For example: -1, 0,
	12678967543233, +100000.

This again is completely unambiguous.


Removing RDF tests that indicate that leading and trailing spaces are not
allowed in these and related datatypes would be a step backward in my view.
Removing these tests on the grounds that the XML Schema specifications are
ambiguous would be a major step backward in my view.

Peter F. Patel-Schneider

NB: In XML Schema whitespace processing is performed before any checking of
    whether a string belongs to a lexical space.  Thus any aspect of
    whitespace processing is irrelevant to the question of what strings
    belong to the lexical space of an XML Schema datatype.
Received on Friday, 12 September 2003 04:08:46 GMT

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