# Re: Range Expressions

```I guess there are also the special cases, which would ignore the 'by' completely:

5 to 5 = (5)
5 to () = ()
() to 5 = ()

Where 5 could be any (allowable) value; I think these are how the construct works now, but please correct me if not!

_________________
Tomos Hillman
eXpertML Ltd
+44 7793 242058
On 7 Dec 2020, 14:42 +0000, Tomos Hillman <yamahito@gmail.com>, wrote:
> I think the most natural syntax would be to interpret the 'direction' of the step by the order of arguments; for me that is implicit by use of the word 'to': I would (naturally) expect:
>
>  5 to 1 by 1 = (5, 4, 3, 2, 1)
>  1 to 5 by 1 = (1, 2, 3, 4, 5)
>  1 to -5 by 1 = (1, 0, -1, -2, -3, -4, -5)
>  1 to 5 by -1 = error
>
> So that the 'by' argument is always positive.
>
> Tom
>
> _________________
> Tomos Hillman
> eXpertML Ltd
> +44 7793 242058
> On 7 Dec 2020, 14:19 +0000, Christian Grün <cg@basex.org>, wrote:
> > I showed the proposed syntax (1 to 5 by -1) to a non-X(Path|SLT|Query)
> > developer, and the immediate response was:
> >
> > You must be wrong, it’s surely supposed to be: 5 to 1 by -1
> >
> > I guess it’s too late to always start counting with the smaller value,
> > or to even allow "5 to 1" for reverse counts. Michael initially
> > proposed to place "by" ahead of "to" [1]…
> >
> > 5 by -1 to 1
> >
> > …and I wonder if it’s not the better choice?
> >
> > [1] https://github.com/expath/xpath-ng/issues/22
> > ____________________________________
> >
> > On Tue, Dec 1, 2020 at 10:02 PM Dimitre Novatchev <dnovatchev@gmail.com> wrote:
> > >
> > > > 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
> >
```

Received on Monday, 7 December 2020 15:18:18 UTC