Writing updates to xml file with XQuery and BaseX -

i have file.xml storing protocols structure following:

<?xml version="1.0" encoding="utf-8" standalone="no"?> <economato>    <protocollo>     <numero>1</numero>     <data>2014-12-15</data>     <oggetto>trasmissione prospetti di rendiconto chiusura esercizio 2012 - beni mobili proprietà dello stato</oggetto>     <destinatario>ragioneria provinciale como</destinatario>     <operatore>maestri</operatore>     <valido>true</valido>   </protocollo>   ... </economato> 

and need change/update value of tag "valido", example 'true' 'false' of protocollo number 1 , update written file. using basex, following documentation have tried write query:

xquery let $update := doc('c:\users\lorenzo enzino  vinci\desktop\economato\databases\2014.xml')//economato/protocollo[numero = 1] return replace value of node $update/valido 'false' doc('c:\users\lorenzo enzino vinci\desktop\economato\databases\2014.xml')//economato 

but error

[xpst0003] unexpected end of query: 'into doc('c:\users\lorenzo enzino vinci\desktop\economato\databases\2014.xml')//economato' 

so query wrong not know where. can me?

it fails, because invalid xquery update syntax. there not replace ... ... ... command, there replace ... ..., error message indicates. unlogical, because $update holds reference correct xml fragment.

so have use following xquery:

let $update := doc('c:\users\lorenzo enzino  vinci\desktop\economato\databases\2014.xml')//economato/protocollo[numero = 1] return replace value of node $update/valido 'false' 

also, please note updates not automatically written files in file system (to avoid accidentally overwriting files), e.g. starting basex -u. explained in detail in basex wiki