Hi,

Using 8.2.3 (and the latest beta) this code seems to be invoking the JSON serializer. I don't understand why. 

declare function local:wrap2($doc,$x as xs:integer*){

 $doc

};

let $b:=doc("file.xml")

return array:for-each([1],local:wrap2($b,?))

And if file.xml is

<doc>

    <p style="prior"/>

    <p style="target"/>

    <p style="later"/>

</doc>

Error:

Improper use? Potential bug? Your feedback is welcome:

Contact: basex-talk@mailman.uni-konstanz.de

Version: BaseX 8.3 beta 89201d1

Java: Oracle Corporation, 1.8.0_45

OS: Windows 7, amd64

Stack Trace: 

java.lang.NullPointerException

at org.basex.util.Token.eq(Token.java:619)

at org.basex.io.serial.json.JsonNodeSerializer.finishOpen(JsonNodeSerializer.java:145)

at org.basex.io.serial.Serializer.prepare(Serializer.java:524)

at org.basex.io.serial.Serializer.openElement(Serializer.java:229)

at org.basex.io.serial.Serializer.node(Serializer.java:437)

at org.basex.io.serial.Serializer.node(Serializer.java:176)

at org.basex.io.serial.StandardSerializer.node(StandardSerializer.java:99)

at org.basex.io.serial.json.JsonNodeSerializer.node(JsonNodeSerializer.java:89)

at org.basex.io.serial.Serializer.serialize(Serializer.java:126)

at org.basex.io.serial.StandardSerializer.serialize(StandardSerializer.java:84)

at org.basex.io.serial.json.JsonSerializer.serialize(JsonSerializer.java:57)

at org.basex.io.serial.json.JsonSerializer.serialize(JsonSerializer.java:76)

at org.basex.io.serial.json.JsonSerializer.function(JsonSerializer.java:120)

at org.basex.io.serial.AdaptiveSerializer.function(AdaptiveSerializer.java:78)

at org.basex.io.serial.Serializer.serialize(Serializer.java:128)

at org.basex.io.serial.AdaptiveSerializer.serialize(AdaptiveSerializer.java:63)

at org.basex.query.value.Value.serialize(Value.java:223)

at org.basex.core.cmd.AQuery.query(AQuery.java:85)

at org.basex.core.cmd.XQuery.run(XQuery.java:22)

at org.basex.core.Command.run(Command.java:398)

at org.basex.core.Command.execute(Command.java:100)

at org.basex.gui.GUI.exec(GUI.java:472)

at org.basex.gui.GUI.access$4(GUI.java:425)

at org.basex.gui.GUI$7.run(GUI.java:412)