hof:until is gone?

On Wed, 2024-03-27 at 23:57 -0400, Graydon Saunders wrote: > > > What's the appropriate pattern for "process a sequence, toggling an > action on or off based on the last member of the sequence we looked > at?"

On Thu, Mar 28, 2024 at 12:14:45AM -0400, Liam R. E. Quin scripsit: > On Wed, 2024-03-27 at 23:57 -0400, Graydon Saunders wrote: > > What's the appropriate pattern for "process a sequence, toggling an > > action on or off based on the last member of the sequence we looked > > at?" > > One approach might be to use fold-left on (1 to count($input)), with > $input in scope, so that you can write in the function argument to > fold-left things like > > if (. eq 1) then $input[.] > else if (starts-with($input[. - 1], 'stab') then... > > etc

From: BaseX-Talk <basex-talk-bounces at mailman.uni-konstanz.de> on behalf of Graydon Saunders <graydonish at gmail.com> Date: Thursday, March 28, 2024 at 7:43 AM To: BaseX <BaseX-Talk at mailman.uni-konstanz.de> Subject: [basex-talk] hof:until is gone? [External Email] Hello -- So I'm trying to do this: import module namespace xcs = "http://www.xcential.com/xquery/utils/script<http://www.xcential.com/xquery/utils/script>" at "same-words-same-order-script.xqm"; (: we don't need xc computationally but there are external variables in that namespace in scope :) import module namespace xc = "http://www.xcential.com/xquery/utils<http://www.xcential.com/xquery/utils>" at 'same-words-same-order.xqm'; declare function xc:dropTableLines($in as node()*,$toggle as xs:boolean) as node()* { switch (true()) case empty($in) return () case starts-with(head($in),':stab') return (<line/>,xc:dropTableLines(tail($in),true())) case starts-with(head($in),':rtab') return (<line/>,xc:dropTableLines(tail($in),false())) case $toggle return (<line/>,xc:dropTableLines(tail($in),$toggle)) default return (head($in),xc:dropTableLines(tail($in),$toggle)) }; let $test as element() := <text> <line></line> <line></line> <line>:stab</line> <line>weasels</line> <line>:stab</line> <line>weasels</line> <line></line> <line></line> <line>:rtab.</line> <line></line> <line>asparagus</line> <line></line> <line></line> <line>:stab</line> <line></line> <line>weasels</line> <line>:rtab.</line> <line>asparagus</line> <line>asparagus</line> <line>asparagus</line> <line>asparagus</line> <line>asparagus</line> <line>:stab</line> <line>:stab</line> <line></line> <line></line> <line>:stab</line> <line></line> <line>weasels</line> <line></line> <line>:rtab.</line> <line></line> <line>asparagus</line> <line></line> <line></line> <line></line> </text> return element {'text'} { xc:dropTableLines($test/line,false()) } Only at scale the stack blows up and I get the "try tail recursion?" suggestion. I would have tried hof:until for that, since I have to pass the current state of "are we dropping or not dropping intervening content?", but it looks like it's been removed? And the available hof functions in 4 look like they're strictly positional which is actively unhelpful in this case. (At least with whatever brain cells I currently have.) What's the appropriate pattern for "process a sequence, toggling an action on or off based on the last member of the sequence we looked at?" Thanks! Graydon

On Thu, 28 Mar 2024 at 12:44, Eliot Kimber <eliot.kimber at servicenow.com> wrote: > This feels like an ideal use case for XSLT for-each-group—something that > is challenging to implement in XQuery. > > > > Cheers, > > > > E. > > > > _____________________________________________ > > *Eliot Kimber* > > Sr Staff Content Engineer > > Digital Content & Design > > O: 512 554 9368 > > M: 512 554 9368 > > servicenow.com <https://www.servicenow.com> > > LinkedIn <https://www.linkedin.com/company/servicenow> | Twitter > <https://twitter.com/servicenow> | YouTube > <https://www.youtube.com/user/servicenowinc> | Facebook > <https://www.facebook.com/servicenow> > > > > *From: *BaseX-Talk <basex-talk-bounces at mailman.uni-konstanz.de> on behalf > of Graydon Saunders <graydonish at gmail.com> > *Date: *Thursday, March 28, 2024 at 7:43 AM > *To: *BaseX <BaseX-Talk at mailman.uni-konstanz.de> > *Subject: *[basex-talk] hof:until is gone? > *[External Email]* > > > ------------------------------ > > Hello -- > > > > So I'm trying to do this: > > > > import module namespace xcs = "http://www.xcential.com/xquery/utils/script" > at "same-words-same-order-script.xqm"; > (: we don't need xc computationally but there are external variables in > that namespace in scope :) > import module namespace xc = "http://www.xcential.com/xquery/utils" at > 'same-words-same-order.xqm'; > > declare function xc:dropTableLines($in as node()*,$toggle as xs:boolean) > as node()* { > switch (true()) > case empty($in) return () > case starts-with(head($in),':stab') return > (<line/>,xc:dropTableLines(tail($in),true())) > case starts-with(head($in),':rtab') return > (<line/>,xc:dropTableLines(tail($in),false())) > case $toggle return (<line/>,xc:dropTableLines(tail($in),$toggle)) > default return (head($in),xc:dropTableLines(tail($in),$toggle)) > }; > > let $test as element() := <text> > <line></line> > <line></line> > <line>:stab</line> > <line>weasels</line> > <line>:stab</line> > <line>weasels</line> > <line></line> > <line></line> > <line>:rtab.</line> > <line></line> > <line>asparagus</line> > <line></line> > <line></line> > <line>:stab</line> > <line></line> > <line>weasels</line> > <line>:rtab.</line> > <line>asparagus</line> > <line>asparagus</line> > <line>asparagus</line> > <line>asparagus</line> > <line>asparagus</line> > <line>:stab</line> > <line>:stab</line> > <line></line> > <line></line> > <line>:stab</line> > <line></line> > <line>weasels</line> > <line></line> > <line>:rtab.</line> > <line></line> > <line>asparagus</line> > <line></line> > <line></line> > <line></line> > </text> > > return element {'text'} { > xc:dropTableLines($test/line,false()) > } > > > > Only at scale the stack blows up and I get the "try tail recursion?" > suggestion. I would have tried hof:until for that, since I have to pass the > current state of "are we dropping or not dropping intervening content?", > but it looks like it's been removed? And the available hof functions in 4 > look like they're strictly positional which is actively unhelpful in this > case. (At least with whatever brain cells I currently have.) > > > > What's the appropriate pattern for "process a sequence, toggling an action > on or off based on the last member of the sequence we looked at?" > > > > Thanks! > > Graydon >

On Thu, Mar 28, 2024 at 01:06:10PM +0000, Andy Bunce scripsit: > hof:until is not gone, it is just hiding [1] > - In 10.7 it is there but undocumented in Wiki

> - In BaseX 11 you need to use XQuery 4 fn:while-do⁺, fn:do-until⁺ [2]

On Thu, Mar 28, 2024 at 5:41 PM Graydon <graydonish at gmail.com> wrote: > Hi Andy -- > > On Thu, Mar 28, 2024 at 01:06:10PM +0000, Andy Bunce scripsit: > > hof:until is not gone, it is just hiding [1] > > - In 10.7 it is there but undocumented in Wiki > > Which is useful to know -- thank you! -- but makes me think a bunch of > my production code is going to break hard when 11 is released. I would > really like to avoid that. (In particular, the conversation with > management about how much refactoring work will be required.) > > > - In BaseX 11 you need to use XQuery 4 fn:while-do⁺, fn:do-until⁺ [2] > > It is very probably my brain, but I'm having trouble transposing > hof:until to those functions. I can an implement what I want to do with > hof:until like so: > > declare function xc:dropTableLinesFancy($in as node()*) as node()* { > let $result as map(*) := > hof:until( > (: are we done? (= we've run off the end of our list of nodes ) :) > function($m) { > empty($m?oldNodes) > }, > (: create new list of line elements :) > function($m) { > map { > 'oldNodes': tail($m?oldNodes), > 'newNodes': ($m?newNodes, > switch (true()) > case starts-with(head($m?oldNodes),':stab') return <line/> > case starts-with(head($m?oldNodes),':rtab') return <line/> > case $m?toggle return <line/> > default return head($m?oldNodes) > ), > 'toggle': ( > switch (true()) > case starts-with(head($m?oldNodes),':stab') return true() > case starts-with(head($m?oldNodes),':rtab') return false() > default return $m?toggle > ) > } > }, > (: initial input = we start with no new nodes :) > map { 'oldNodes': $in, 'newNodes': (), 'toggle': false() } > ) > return $result?newNodes > }; > > Anyone willing to provide an example of what that would look like in > fn:while-do or fn:do-until? > > Thanks! > Graydon > > > -- > Graydon Saunders | graydonish at fastmail.com > Þæs oferéode, ðisses swá mæg. > -- Deor ("That passed, so may this.") >

On Thu, 28 Mar 2024 at 18:34, Christian Grün <christian.gruen at gmail.com> wrote: > Hi Graydon, > > Folks tell us it’s time to stop delaying BaseX 11… We’re trying hard. > > The good news: The only difference between hof:until [1] and fn:do-until > [2] is the order of parameters. The following queries will do the same > thing: > > hof:until(function($a) { $a > 16 }, function($a) { $a * 2 }, 1) > do-until(1, function($a) { $a * 2 }, function($a) { $a > 16 }) > > With fn:do-until, the input has moved to the first position, the action > comes second and the predicate comes last. > > Hope this helps, > Christian > > [1] https://files.basex.org/releases/10.0/BaseX100.pdf > [2] > https://qt4cg.org/specifications/xpath-functions-40/Overview.html#func-do-until > > > > On Thu, Mar 28, 2024 at 5:41 PM Graydon <graydonish at gmail.com> wrote: > >> Hi Andy -- >> >> On Thu, Mar 28, 2024 at 01:06:10PM +0000, Andy Bunce scripsit: >> > hof:until is not gone, it is just hiding [1] >> > - In 10.7 it is there but undocumented in Wiki >> >> Which is useful to know -- thank you! -- but makes me think a bunch of >> my production code is going to break hard when 11 is released. I would >> really like to avoid that. (In particular, the conversation with >> management about how much refactoring work will be required.) >> >> > - In BaseX 11 you need to use XQuery 4 fn:while-do⁺, fn:do-until⁺ [2] >> >> It is very probably my brain, but I'm having trouble transposing >> hof:until to those functions. I can an implement what I want to do with >> hof:until like so: >> >> declare function xc:dropTableLinesFancy($in as node()*) as node()* { >> let $result as map(*) := >> hof:until( >> (: are we done? (= we've run off the end of our list of nodes ) :) >> function($m) { >> empty($m?oldNodes) >> }, >> (: create new list of line elements :) >> function($m) { >> map { >> 'oldNodes': tail($m?oldNodes), >> 'newNodes': ($m?newNodes, >> switch (true()) >> case starts-with(head($m?oldNodes),':stab') return <line/> >> case starts-with(head($m?oldNodes),':rtab') return <line/> >> case $m?toggle return <line/> >> default return head($m?oldNodes) >> ), >> 'toggle': ( >> switch (true()) >> case starts-with(head($m?oldNodes),':stab') return true() >> case starts-with(head($m?oldNodes),':rtab') return false() >> default return $m?toggle >> ) >> } >> }, >> (: initial input = we start with no new nodes :) >> map { 'oldNodes': $in, 'newNodes': (), 'toggle': false() } >> ) >> return $result?newNodes >> }; >> >> Anyone willing to provide an example of what that would look like in >> fn:while-do or fn:do-until? >> >> Thanks! >> Graydon >> >> >> -- >> Graydon Saunders | graydonish at fastmail.com >> Þæs oferéode, ðisses swá mæg. >> -- Deor ("That passed, so may this.") >> >

On Thu, Mar 28, 2024 at 07:33:51PM +0100, Christian Grün scripsit: > Hi Graydon,

> Folks tell us it’s time to stop delaying BaseX 11… We’re trying hard.

> The good news: The only difference between hof:until [1] and fn:do-until > [2] is the order of parameters. The following queries will do the same > thing: > > hof:until(function($a) { $a > 16 }, function($a) { $a * 2 }, 1) > do-until(1, function($a) { $a * 2 }, function($a) { $a > 16 }) > > With fn:do-until, the input has moved to the first position, the action > comes second and the predicate comes last.