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.lettere@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" kristian@keeleleek.ee 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.lettere@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.