Tuple types

[John Snelson]

Pavel Minaev wrote:
> On Tue, Sep 1, 2009 at 6:44 AM, John Snelson<http://x-query.com/mailman/listinfo/talk> wrote:
>> Tuple types won't make it into XQuery 1.1, but the closures support in
>> higher order functions allows you to effectively return sequences of
>> sequences:
>>
>> (: Wrap a sequence as a function item :)
>> declare function local:ref($arg as item()*) as function() as item()*
>> {
>>    function() { $arg }
>> };
>>
>> (: Unwrap a sequence from a function item :)
>> declare function local:deref($arg as function() as item()*) as item()*
>> {
>>    $arg()
>> };
> 
> This makes sense, though it would be a nuisance to have to define
> ref() and deref() every time. Is there any consideration to make them
> standard library functions?

My recollection is that the WG considered adding them and rejected the 
idea on the grounds that functions that can be defined in XQuery itself 
better belong in something like EXPath function modules. It's highly 
likely that I'll submit such a module to EXPath in the future.

John

-- 
John Snelson, Oracle Corporation            http://snelson.org.uk/john
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