Re: Debugging Python scripts

[Steve Litt <slitt troubleshooters com>]

On Sun, 20 Dec 2015 10:33:53 +0000
Rob Wortham <r h wortham gmail com> wrote:

> I am trying to use Python scripting in Dia to export a hierarchical
> diagram in a specific format. I'm new to Python. 

IMHO the questions you ask here are Dia interface questions more than
Python questions. Although my answers aren't responsive to your exact
questions, you might find them helpful.

> I see that
> codegen.py is almost what I need, so I plan to take that as a
> starting point. Because I'm new to Python I'll need to iterate and
> learn to get this coded.

My Dia has no Python scripting, and I don't know what codegen.py is,
but...

> Just a couple of hopefully straightforward questions ...
>
> 1. Where does print send its data (for debugging)? It does not seem
> to send it to the Dia Python console. Where is stdout? 

If you just zless yourdiagram.dia | yourpgm.py , then stdout will be the
terminal unless you redirect the output.

> 2. How can I
> get Dia to reload the script as I edit it. At the moment changes only
> seem to take effect if Dia is stopped and restarted.

This becomes a moot question if you run your python program against the
Dia diagram file on the command prompt.

One more thing. If you put the following line:

from lxml import etree

near the top of your program, then you have an XML parser with which
you can disect any ungzipped XML and have your way with it.

You could also use:

import xml.etree.ElementTree as ET

but in my opinion the former XML parser is more useful than the latter
for most work.

I know this wasn't responsive to your question, but I hope it helps.

SteveT

Steve Litt 
November 2015 featured book: Troubleshooting Techniques
     of the Successful Technologist
http://www.troubleshooters.com/techniques