Awesome Leo, thanks!
Similar to what I was thinking about but with a lot or after-thought
optimization!
Great suggestion.
M.
Il 01 nov 2017 1:59 PM, "Leonard Wörteler" <
leonard.woerte...@uni-konstanz.de> ha scritto:
> Hi Marco,
>
> I also do not know of a built-in way to do this, but here is my shot at an
> implementation in XQuery. It uses fast exponentiation [1] and throws a
> custom error if there is more than one "e" in the input.
>
> Hope that helps (or is of interest), I had fun hacking it together,
> Leo
>
> declare function local:pow($n, $k) {
> if($k eq 0) then xs:decimal('1')
> else if($k eq 1) then $n
> else (
> let $d := $k idiv 2,
> $m := $k mod 2
> return if($m eq 0) then local:pow($n * $n, $d)
> else local:pow($n * $n, $d) * $n
> )
> };
>
> declare function local:parse-decimal($str as xs:string) as xs:decimal {
> let $parts := tokenize($str, '[eE]')
> return switch(count($parts))
> case 1 return xs:decimal($str)
> case 2 return (
> let $exp := xs:long($parts[2]),
> $base := xs:decimal($parts[1]),
> $b10 := if($exp gt 0) then xs:decimal('10') else
> xs:decimal('0.1')
> return $base * local:pow($b10, $exp)
> )
> default return error(xs:QName('local:NODECIML'), 'Wrong format: '
> || $str)
> };
>
> local:parse-decimal('123.45e-300')
>
> [1] https://en.wikipedia.org/wiki/Exponentiation_by_squaring
>
> Am Mittwoch, 01. November 2017 13:21 CET, Marco Lettere <
> m.lett...@gmail.com> schrieb:
> > Thanks Kristian,
> > unfortunately this introduces rounding errors which I'm trying to avoid
> > because managing units, measures and monetary amounts.
> > M.
> >
> > Il 01 nov 2017 12:57 PM, "Kristian Kankainen" ha
> > scritto:
> >
> > You need to use xs:float or xs:double instead of xs:decimal to be able to
> > use the 'e' or 'E' as the exponent separator.
> >
> > Br,
> > Kristian K1. nov 2017 13:18 kirjutas kuupäeval Marco Lettere <
> > m.lett...@gmail.com>:
> > >
> > > Hi all,
> > >
> > > I thought of asking this in parallel of hacking my own parsing
> procedure
> > > ...
> > >
> > > Is there a native way to parse scientific notation string into
> > > xs:decimal since a direct casting (xs:decimal("1e1")) is not allowed?
> > >
> > > Thanks,
> > >
> > > Marco.
> > >
>
>
