On Fri, 2021-06-04 at 12:35 -0400, Graydon Saunders wrote:
>
> declare function local:subtractSentences($before as xs:string*,$after
> as
> xs:string*) as xs:string* {
>
> let $thisBefore as xs:string? := head($before)
> let $thisAfter as xs:string? := head($after)
>
> return
> if (not(exists($thisBefore)) or not(exists($thisAfter)))
> then $after (: we're done because we're out of strings, but if we
> have
> any after left we want it :)
> else if (ends-with($thisAfter,$thisBefore))
> then
> (replace($thisAfter,$thisBefore,''),local:subtractSentences(tail($bef
> ore),tail($after)))
> else ($thisAfter,local:subtractSentences($before,tail($after)))
> };
I'd be tempted to do this by constructing a regular expression on the
fly, mapping whitespace in the input to \s+ in the expression and
quoting \ elsewhere, and use a single replace().
Your problem is likely (ididn't check the BaseX query plan) that your
final sequence constructor precludes tail optimization.
($thisAfter,local:subtractSentences($before,tail($after))
either use one of the fold-left or fold-right functions, or pass
$thisAfter as an argument to your function and return it at the end,
perhaps.
Liam
--
Liam Quin, https://www.delightfulcomputing.com/
Available for XML/Document/Information Architecture/XSLT/
XSL/XQuery/Web/Text Processing/A11Y training, work & consulting.
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