[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: Implicit casting from double to float

Subject: Re: Implicit casting from double to float
From: David Carlisle <davidc@xxxxxxxxx>
Date: Wed, 7 Jan 2009 12:33:04 GMT
Re:  Implicit casting from double to float
Well... I don't find it surprising that you can find a result that
differs from Java, the type systems are different so there will be
differences. 

However I can't actually verify that this should work in XSLT. (Without
thinking too hard, and it's probably just easier to mumble and get
Michael to point to the right bit of the spec:-)

xsl:variable uses function conversion rules, so we seem to arrive at
point 3 in (the third list in)
http://www.w3.org/TR/xpath20/#id-function-calls

> 3. For each numeric item in the atomic sequence that can be promoted to the
>    expected atomic type using numeric promotion as described in B.1 Type
>    Promotion, the promotion is done. 

so the question is, can we get from a double to a float?

B.1 Type Promotion

> A value of type xs:float (or any type derived by restriction from
> xs:float) can be promoted to the type xs:double 

so that's the wrong direction,


> A value of type xs:decimal (or any type derived by restriction from
> xs:decimal) can be promoted to either of the types xs:float or
> xs:double. The result of this promotion is created by casting the
> original value to the required type. This kind of promotion may cause
> loss of precision. 


so that's the right direction, but going from decimal to float (losing
precision) not double to float.



so, I think that numeric promotion doesn't convert a double to a float,
so the question is do they match anyway, and that question is answerd by
the  SequenceType matching  rules. I think the answer is no, as xsd:float
isn't derived from xsd:double.

David

________________________________________________________________________
The Numerical Algorithms Group Ltd is a company registered in England
and Wales with company number 1249803. The registered office is:
Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom.

This e-mail has been scanned for all viruses by Star. The service is
powered by MessageLabs. 
________________________________________________________________________

Current Thread

PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
Email
First Name
Last Name
Company
Subscribe in XML format
RSS 2.0
Atom 0.3
Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.