Hi Rob,

this behaves as expected. The default for parameter $exec only applies, when you omit the argument, as in

local:test()

But in your example, the function item is the empty sequence, so you are effectively doing

()("a", "b")

which by definition results in the empty sequence:

Best regards

Gunther

Gesendet: Samstag, 14. Februar 2026 um 09:57

Von: "Rob Stapper via BaseX-Talk" <basex-talk@mailman.uni-konstanz.de>

An: "basex-talk@mailman.uni-konstanz.de" <basex-talk@mailman.uni-konstanz.de>

Betreff: [basex-talk] function as default parameter

Good morning,

I came across some unexpected behaviour when using a function as a default functionparameter:

declare function local:test
( $exec as function(*)? := fn( $a, $b) { $a => trace("test1: ") }
)
{ $exec( "a", "b")
} ;
local:test(())

I would expect a trace- and a execution result, but I got nothing. Are my expectations wrong or could it be a bug?

PS code snipped added as test.xqm

PS The optimized query shows an empty value.

mvgr.

Rob Stapper