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Re: abstract data types in XQuery? information hiding?

• From: "Liam R. E. Quin" <liam@fromoldbooks.org>
• To: "C. M. Sperberg-McQueen" <cmsmcq@blackmesatech.com>, XML Dev <xml-dev@l...>
• Date: Mon, 17 Jun 2024 22:27:32 -0400

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


-- 
Liam Quin, https://www.delightfulcomputing.com/
Available for XML/Document/Information Architecture/XSLT/
XSL/XQuery/Web/Text Processing/A11Y training, work & consulting.
Barefoot Web-slave, antique illustrations:  http://www.fromoldbooks.org

• Follow-Ups:
  • Re: abstract data types in XQuery? information hiding?
    • From: Adam Retter <adam.retter@googlemail.com>

• References:
  • abstract data types in XQuery? information hiding?
    • From: "C. M. Sperberg-McQueen" <cmsmcq@blackmesatech.com>