Re: Range Expressions

> Apart from anything else, it loses the idioms in the current language
that rely on a range being a sequence of integers,
> enabling familiar constructs such as x[position() = 1 to 10].

Well, there is nothing wrong with series of time periods in a total time
range.

Maybe we can have a lifted overload of range, providing a function that,
when applied on the provided as integers start, end and step, will produce
the actual start, end and step for the actual range:

range($startBase as xs:integer,
      $endBase as xs:integer,
      $stepBase as xs:integer,
      $provider as function(xs:integer) as item() )
   as item()*

So, the provider() or better name, will convert the integers to whatever
typed-data we need.

Thanks,
Dimitre

On Tue, Dec 1, 2020 at 11:31 AM Michael Kay <mike@saxonica.com> wrote:

> This feels to me like a step too far. If we had an object-oriented
> language with strong infrastructure for new types like this then it might
> be the right thing to do, but at present it doesn't blend in well. Apart
> from anything else, it loses the idioms in the current language that rely
> on a range being a sequence of integers, enabling familiar constructs such
> as x[position() = 1 to 10].
>
> Michael Kay
> Saxonica
>
> On 1 Dec 2020, at 16:50, Dimitre Novatchev <dnovatchev@gmail.com> wrote:
>
> I would rather prefer this to be a system-provided  *record  *type. Name
> it   range
>
> record(start? xs:integer, end? xs:integer, step? xs:integer)
>
> Then one can provide a set of functions defined on the range type (and
> using the arrow operator comes handy here)
>
>      range?start
>   range?end
>   range?step
>
>   sequence($r as range) as xs:integer*
>   size($r as range) as xs:integer
>   index-at($r as range, $pos as xs:integer) as xs:integer
>   reverse($r as range) as range
>
> Thanks,
> Dimitre
>
> On Mon, Nov 30, 2020 at 6:05 AM Michael Kay <mike@saxonica.com> wrote:
>
>> Someone, I forget who, gave feedback suggesting making "by" a binary
>> operator so
>>
>> 1 to 10 by 2 means ((1 to 10) by 2) i.e. 1, 3, 5, 7, 9
>> 1 to 10 by -1 gives 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
>> ("A", "B", "C", "D") by 2 gives ("A", "C")
>> ("A", "B", "C", "D") by -2 gives ("D", "B")
>>
>> I've adopted this suggestion in my latest draft.
>>
>> Michael Kay
>> Saxonica
>>
>
>
>

-- 
Cheers,
Dimitre Novatchev
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