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Re: question about subtyping and type annotations

From: Frans Englich <frans.englich@telia.com>
Date: Fri, 24 Feb 2006 18:15:41 +0000
To: www-ql@w3.org
Message-Id: <200602241815.41306.frans.englich@telia.com>

On Friday 24 February 2006 16:57, you wrote:
> > Section 3.12.5 Constructor Functions seems to be pretty clear
> > about it:
>
> That only says they are equivalent to casts. Are casts exempt from the
> general rule of substitutability, which says that any expression can return
> a value whose dynamic type is a subtype of the required type?

Another question is what the negative impact, if any, is when returning say 
xs:byte when xs:integer is the static type(apart from Per Bothner's confusion 
when investigating these corner cases).


		Frans
Received on Friday, 24 February 2006 18:04:16 UTC

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