Mike, please can you show us a real-world example of fn:trace in action? Regards Steve Hanson Architect, IBM Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh@uk.ibm.com tel:+44-1962-815848 From: Mike Beckerle <mbeckerle.dfdl@gmail.com> To: dfdl-wg@ogf.org, Date: 16/07/2013 15:03 Subject: [DFDL-WG] proposal: add fn:trace function to DFDL Sent by: dfdl-wg-bounces@ogf.org I have found working with DFDL expressions basically impossible without the fn:trace function to help debug them. I am not sure how I would write a tutorial about expressions without using fn:trace in it to illustrate what is going on in the expressions. In the interests of keeping the tutorials portable I suggest we add the fn:trace function. fn:trace($value as item()*, $label as xs:string) as item()* Summary: Provides an execution trace intended to be used in debugging queries. The notation item()* means any node sequence including an empty node sequence. The input $value is returned, unchanged, as the result of the function. In addition, the inputs $value, converted to an xs:string, and $label may be directed to a trace data set. The destination, format, and ordering of the output of this trace data set is implementation specific. Related Issue: I don't see any language in the spec where we flat out say that a node sequence in the expression language is a sequence of Infoset Element Information Items. We should add this near the begining of section 23. -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com -- dfdl-wg mailing list dfdl-wg@ogf.org https://www.ogf.org/mailman/listinfo/dfdl-wg Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU