Re: [Exist-development] bug @fn:string

[Dmitriy S. <sha...@gm...>]

On Mon, 2010-08-09 at 18:31 +0200, Pieter Deelen wrote:
> On Mon, Aug 9, 2010 at 5:32 PM, Dmitriy Shabanov <sha...@gm...> wrote:
> > On Mon, 2010-08-09 at 16:32 +0200, Pieter Deelen wrote:
> >> xs:string(()) should yield ()
> >
> > It's confuse me, can you point spec.
> 
> http://www.w3.org/TR/xquery/#id-constructor-functions states (T is a
> type, e.g., xs:string):
> "The semantics of the constructor function call T($arg) are defined to
> be equivalent to the expression (($arg) cast as T?)"
> 
> So xs:string(()) is equivalent to () cast as xs:string?.
> 
> http://www.w3.org/TR/xquery/#id-cast tells us what this means:
> "If the result of atomization [of the input expression] is an empty sequence:
>   1. If ? is specified after the target type, the result of the cast
> expression is an empty sequence.
>   2. If ? is not specified after the target type, a type error is
> raised [err:XPTY0004]."
> 
> Hence, () cast as xs:string? evaluates to (). xs:string(()),
> therefore, also evaluates to ().

That is the strangers part of the spec. I have to agree :-/

-- 
Cheers,

Dmitriy Shabanov