Debug XQuery Program

Question

In the beginning, I wrote a little XQuery script that was designed to do a small task and only that. Now it came out that this XQuery script is anything but complete, and I have

Answer 1

Something that I would need would be:

print something to the command line to check weather the progroms has the correct nodes at that time.

Use the standard XPath 2.0 function trace().

a debugging tool that shows me the stored variables

There are varios IDEs for XQuery that come up with a Debugger. For example, have a look at oXygen.

Answer 2

There are few Xml Database centric diagnostics apis. w.r.t to MarkLogic Xml Database.

1. Diagnostics/ TaskServer UI in the admin console.
2. Tabular Profile use their CQ application
3. xdmp:query-trace(), xdmp:trace() are api gives some idea about the Query plan.
4. opensource Xquery Debugger = xqdebug

are few techniques to have effective coding.

Answer 3

As Dimitre suggested, trace() is what I fall back on when nothing else works. Messy but it works.

Instead of: $foo := anyXqueryExpression

Do this: $foo := trace(anyXqueryExpression, "text")

Logs the result of executing anyXqueryExpression and adds the prefix "text".