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XML schema draft comments: 3.2.15.1: hexBinary example octets not clear

From: Daniel Barclay <daniel@fgm.com>
Date: Thu, 10 Jun 2004 11:55:34 -0400
Message-ID: <40C88476.80404@fgm.com>
To: www-xml-schema-comments@w3.org

Regarding the draft at
http://www.w3.org/TR/2004/PER-xmlschema-2-20040318/:

Section 3.2.15.1 says:

   hexBinary has a lexical representation where each binary octet is
   encoded as a character tuple, consisting of two hexadecimal digits
   ([0-9a-fA-F]) representing the octet code.  For example, "0FB7" is
   a hex encoding for the 16-bit integer 4023 (whose binary representation
   is 111110110111).

The example doesn't match the preceding specification:

The specification deals only with the mapping from an octet to a
tuple of hexadecimal digits.  Specifically, it does not address
any mapping from binary terms wider than octets to octets.

Therefore, the example should directly show a mapping from octets
to digits.  However, it does not.  It obscures that mapping by also
involving a mapping from a 16-bit integer to a sequence of octets.

Also, the example should not assume that that mapping is big-endian
unless that is specified somewhere.


(Additionally, the specification never actually says that the
encodings of octets (the character tuples) appear in the same
order as the sequence of octets they encode.  By the way, section
2.5.1.2, List datatypes, also seems to neglect to specify the
correspondence in order.)

Daniel
Received on Thursday, 10 June 2004 11:56:11 UTC

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