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RE: [XML Schema 1.1] Why is it called precisionDecimal? Why isn't it called precisionFloat? Or precisionDouble?

From: Michael Kay <mike@saxonica.com>
Date: Mon, 15 Jun 2009 23:33:08 +0100
To: "'Costello, Roger L.'" <costello@mitre.org>, <xmlschema-dev@w3.org>
Message-ID: <218CF0C76AD249158AF9E63A4D2A0DB8@Sealion>
The data type has three interesting characteristics:

* it's decimal rather than binary

* the implementation is typically floating point rather than fixed point

* the precision is part of the value space

If you can find a name that reflects all three characteristics, please
suggest it! But I would suggest that the second is the least important - if
nothing else because a fixed-point implementation is theoretically possible.

PrecisionDouble would be completely misleading because there's nothing
"double" about it, and precisionFloat would be potentially misleading
because some people might assume it indicated some relationship to the
current float type, and to the float type in other well-known languages,
which is binary rather than decimal.

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay 
 

> -----Original Message-----
> From: xmlschema-dev-request@w3.org 
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of Costello, Roger L.
> Sent: 15 June 2009 19:21
> To: xmlschema-dev@w3.org
> Subject: [XML Schema 1.1] Why is it called precisionDecimal? 
> Why isn't it called precisionFloat? Or precisionDouble?
> 
> 
> Hi Folks,
> 
> A precisionDecimal value is a decimal value, and its 
> precision is inferred from how it is lexically expressed. 
> Here's a legal precisionDecimal value:
> 
>    3.00e2
> 
> But this is not a legal xs:decimal value. It looks more like 
> a float or double value.
> 
> Why isn't it called precisionFloat, or precisionDouble?
> 
> /Roger
Received on Monday, 15 June 2009 22:33:42 GMT

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