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[Bug 5229] Definition of xs:double

From: <bugzilla@wiggum.w3.org>
Date: Wed, 27 Feb 2008 01:29:12 +0000
To: www-xml-schema-comments@w3.org
Message-Id: <E1JUB6e-00023t-ED@wiggum.w3.org>


cmsmcq@w3.org changed:

           What    |Removed                     |Added
             Status|NEW                         |ASSIGNED

------- Comment #2 from cmsmcq@w3.org  2008-02-27 01:29 -------
Like Dave, I have reviewed the textual history of this passage without
finding much enlightenment.  As far as I can tell, the only exception
to which its plausible for the reference to be pointing to is the note,
in some earlier versions of the spec, that our float and double types
have a single NaN, whereas IEEE postulates a large class of NaNs which
are not identical but also not always meaningfully disgintuishable.
The reference, however, appears to have been introduced at the same time
the note aobut the NaNs was deleted.

Without deep confidence, therefore, I diagnose editorial error (adding
a pointer to the sentence about NaNs, then deleting that sentence
without deleting the pointer).  With slightly more confidence, I propose
a simple fix:  delete the phrase "with the minor exception noted below"
both from the description of float and from that of double.

On the intensional / extensional tension; the phrasing "The double 
datatype is the IEEE double-precision 64-bit floating point datatype"
is perhaps imperfect:  xsd:double clearly has properties specific to
XSD, and while there is not much doubt that IEEE can be described in terms
of a value space and a lexical space and mappings between them, it's also
clear that such a description is our work, not that of IEEE.

We might consider replacing "is" with a verb like "mirrors", if that 
helps.  But unless there is some more specific instance of an apparent
conflict between intension and extension, I propose to do nothing much about
the second observation in the bug report.

To summarize:  (1) delete "with the minor exception noted below" (twice),
and (2) optionally replace "is" with "mirror" (or another verb that
commands consensus in the WG).
Received on Wednesday, 27 February 2008 01:29:19 UTC

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