Guide to Blend debugging

Manual debugging

In practice, the most common way to debug a Blend script is simply to insert temporary statements that provide messages or output for yourself as a developer to inspect. When you are done debugging, you remove these statements. To write output to the console during script execution, call:

<pc:ConsoleWrite>

To output data elements as a response to the console, perhaps in order to see whether certain data are available, for string data, call:

<pc:value-of>

and, for node sets, call:

<pc:copy-of>

To send this type of debug information to a file instead of the console, redirect it:

> *usoft-bindir*\ublendit.exe *script-file* >log.xml

When debugging long scripts, you can temporarily skip sections by commenting them out:

<!--  -->

but it is often more practical to debug code blocks as stand-alone scripts and paste the result back into the original script when you are satisfied with it. To debug longer sections, clone the entire Blend script as a second .XML file, remove from this second script all the sections you are not interested in, debug what remains, and paste the debugged code back into the original.

Tracemode tool

When you run a Blend script with the tracemode option:

> *usoft-bindir*\ublendit.exe *script-file* tracemode

a browser-based debugging tool is presented. This tool allows you to inspect script processing in a number of ways. For example, this tool allows you to:

• Expand and collapse script sections.
• Inspect variable values by hovering a variable placeholder.

After use, if you want to re-run the script, you must remember to first close the browser window created by tracemode.

Detecting obsolete code

You can get warnings that you are using Blend commands that are either obsolete or deprecated. Add obsoleted=true when you give the command:

> *usoft-bindir*\ublendit.exe *script-file* obsoleted=true

This causes the following type of warning to appear on the console:

pc:assign is obsoleted. Use pc:assign-string