Hi again,

I found a much simpler way to reproduce the error, without XQS:

xquery version "3.1";
element { 'elementname' } {
attribute { QName('', 'attrname') } { 'attrval' }
,
xquery:eval('true()')
}

Thanks,
Amanda

On Thursday, April 16th, 2026 at 12:51 PM, Amanda Galtman via BaseX-Talk <basex-talk@mailman.uni-konstanz.de> wrote:
Hi, BaseX team.

I tried to use BaseX 12.3 with XSpec to test Schematron schemas with Andrew Sales's XQS implementation. I ran into an error.

[XPST0017] Unknown function: true (similar: fn:true).

I am not sure if the underlying issue is coming from BaseX or XQS or both. I simplified the query that reproduces the error, but the query still relies on XQS. I briefly tried to reproduce the problem without XQS but haven't been successful yet.

Reproduction steps are in the GitHub issue that I created in the XQS repo. Does it ring a bell with any BaseX experts?
https://github.com/AndrewSales/XQS/issues/87

Thanks,
Amanda