basex - XQuery: declare a function returning nothing -

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declare variable $testseq item()* := ();  declare function local:insertseq($target item()*, $position xs:integer?, $inserts item()*) item()* (:might great if have keyword represent nothing:) {   fn:insert-before($target, 1, $inserts) (:change global sequence:)   () (:simulate returning nothing, empty sequence:) };  element test {   attribute haha {"&"},   local:insertseq($testseq, 1, ('a', 'b')),   $testseq }

i need collect global sequence while script running. @ end of script release sequence. function insertseq must return nothing. possible xquery? or there other tricks it?

error basex:

$ basex test.xqy stopped @ /users/jack/documents/shk/xsd2owl/workspace/xqy/test.xqy, 7/4: [xpty0004] item expected, sequence found: ("a", "b").

the answer on title of original question be:

declare function local:f() empty-sequence() {   () };

as want solve specific problem, think creating new question title , corresponding problem description (including tiny example expected input , output).

in functional languages, such xquery, variables cannot reassigned once have been defined (see referential transparency). consequence, you’ll need use recursive functions repeatedly add values sequence. fn:fold-left can used well: feels challenging when being used first time, once understand does, don’t want miss is.


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