Re: [xml-dev] abstract data types in XQuery? information hiding?

["Liam R. E. Quin" <liam@fromoldbooks.org>]

On Mon, 2024-06-17 at 11:35 -0600, C. M. Sperberg-McQueen wrote:
> 
> Since XQuery doesn't have the ability to declare new type names (or
> am I
> missing something very important?), I don't see a straightforward way
> to
> do this inside of XQuery.

You can import a schema, but overall i agree with Mike Kay here that
XML and the qt stack is really not very amenable to data hiding.

There’s a qt4 proposal i think to add a typedef, but that’s an alias
for an existing type i think.

Providing a function-based interface to a type might get you some of
the way. Better yet, divorce types from the processing, and provide a
Java-style functional interface, 
    socks:get-pair()
    socks:get-colour($which as dt:leftRight)
    socks:wash($socks as item()*)
and here, wash() would check using instance of that it was passed the
right type, and you could use a different implementation, with a
different namespace binding of the socks prefix, and maybe you can
accomplish what you want indirectly?

liam


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