sequences after the path operator
Friday, 7 July 2023 · 3 messages
GS
Graydon Saunders7 Jul 2023 05:32 #
Hello --
Using BaseX 10.6, the test query
let $test as xs:string := "And O Lord the pride of man, broken in the dust again"
let $syntax1 as xs:string :=
analyze-string($test,'\p{Lu}')/(fn:match/concat('[',.,']'),fn:non-match/string())
=> string-join('')
let $syntax2 as xs:string :=
analyze-string($test,'\p{Lu}')/*/(self::fn:match/concat('[',.,']'),self::fn:non-match/string())
=> string-join('')return ($syntax1,$syntax2)
produces
[A][O][L]nd ord the pride of man, broken in the dust again
[A]nd [O] [L]ord the pride of man, broken in the dust again
I'm surprised by this, because I expected document order to apply to the result of analyze-string and for syntax1 to work in the sense of having the results emerging in the same order as the input.
Have I miscomprehended something? Anyone care to have a go at explaining why syntax1 doesn't maintain the order of the input? (I'm possibly mistakenly confident that I understand why syntax2 does.)
Thanks!
Graydon
--
Graydon Saunders | graydonish at fastmail.com
Þæs oferéode, ðisses swá mæg.
-- Deor ("That passed, so may this.")
CG
Christian Grün7 Jul 2023 09:17 #
Hi Graydon,
The document order can only be restored if the result of an expression is a sequence of nodes. In the given case, …
analyze-string($test,'\p{Lu}')/(
fn:match/concat('[',.,']'),
fn:non-match/string()
)
…two string sequences are generated (for matches and non-matches) which have no inherent relationship to the original nodes:
• matches: ”[A]”, ”[O]”, ”[L]”
• non-matches: ”nd”, “ ”, “ord the …”
You have already presented a version that works. Here’s another one-liner that creates a new result for each (non-)match element in the original order:
let $syntax2 := string-join(analyze-string($test,'\p{Lu}')/* ! (if(self::fn:match) then '[' || . || ']' else .))
Hope his helps,
Christian
Quoted text · Graydon Saunders · 30 lines
On Fri, Jul 7, 2023 at 3:32 AM Graydon Saunders <graydonish at gmail.com> wrote: > > Hello -- > > Using BaseX 10.6, the test query > > let $test as xs:string := "And O Lord the pride of man, broken in the dust again" > > let $syntax1 as xs:string := analyze-string($test,'\p{Lu}')/(fn:match/concat('[',.,']'),fn:non-match/string()) => string-join('') > > let $syntax2 as xs:string := analyze-string($test,'\p{Lu}')/*/(self::fn:match/concat('[',.,']'),self::fn:non-match/string()) => string-join('') > > return ($syntax1,$syntax2) > > produces > > [A][O][L]nd ord the pride of man, broken in the dust again > [A]nd [O] [L]ord the pride of man, broken in the dust again > > I'm surprised by this, because I expected document order to apply to the result of analyze-string and for syntax1 to work in the sense of having the results emerging in the same order as the input. > > Have I miscomprehended something? Anyone care to have a go at explaining why syntax1 doesn't maintain the order of the input? (I'm possibly mistakenly confident that I understand why syntax2 does.) > > Thanks! > Graydon > > -- > Graydon Saunders | graydonish at fastmail.com > Þæs oferéode, ðisses swá mæg. > -- Deor ("That passed, so may this.")
GS
Graydon Saunders7 Jul 2023 18:48 #
Hi Christian --
*> The document order can only be restored if the result of an expression is a sequence of nodes.*
Thank you! That does help, in as much as I was thinking that the order came from the left side, not the right side. I feel much less confused now.
(I used an if in the original of the real code from which the example was derived and my brain kept insisting it was inaesthetic, presumably from too much xsl:apply-templates.)
Much appreciated!
Graydon
Quoted text · Christian Grün · 70 lines
On Fri, Jul 7, 2023 at 3:17 AM Christian Grün <christian.gruen at gmail.com> wrote: > Hi Graydon, > > The document order can only be restored if the result of an expression > is a sequence of nodes. In the given case, … > > analyze-string($test,'\p{Lu}')/( > fn:match/concat('[',.,']'), > fn:non-match/string() > ) > > …two string sequences are generated (for matches and non-matches) > which have no inherent relationship to the original nodes: > > • matches: ”[A]”, ”[O]”, ”[L]” > • non-matches: ”nd”, “ ”, “ord the …” > > You have already presented a version that works. Here’s another > one-liner that creates a new result for each (non-)match element in > the original order: > > let $syntax2 := string-join(analyze-string($test,'\p{Lu}')/* ! > (if(self::fn:match) then '[' || . || ']' else .)) > > Hope his helps, > Christian > > > On Fri, Jul 7, 2023 at 3:32 AM Graydon Saunders <graydonish at gmail.com> > wrote: > > > > Hello -- > > > > Using BaseX 10.6, the test query > > > > let $test as xs:string := "And O Lord the pride of man, broken in the > dust again" > > > > let $syntax1 as xs:string := > analyze-string($test,'\p{Lu}')/(fn:match/concat('[',.,']'),fn:non-match/string()) > => string-join('') > > > > let $syntax2 as xs:string := > analyze-string($test,'\p{Lu}')/*/(self::fn:match/concat('[',.,']'),self::fn:non-match/string()) > => string-join('') > > > > return ($syntax1,$syntax2) > > > > produces > > > > [A][O][L]nd ord the pride of man, broken in the dust again > > [A]nd [O] [L]ord the pride of man, broken in the dust again > > > > I'm surprised by this, because I expected document order to apply to the > result of analyze-string and for syntax1 to work in the sense of having the > results emerging in the same order as the input. > > > > Have I miscomprehended something? Anyone care to have a go at > explaining why syntax1 doesn't maintain the order of the input? (I'm > possibly mistakenly confident that I understand why syntax2 does.) > > > > Thanks! > > Graydon > > > > -- > > Graydon Saunders | graydonish at fastmail.com > > Þæs oferéode, ðisses swá mæg. > > -- Deor ("That passed, so may this.") >
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