[IPython-user] debugging in ipython

Tom Krauss tpk@kraussfamily....
Wed Oct 22 20:51:43 CDT 2008

Note, I have resolved these questions through other channels and  
thought a follow-up post might be appropriate.

On Oct 18, 2008, at 9:41 AM, Tom K. wrote:

> I had a question about debugging in ipython [sorry if this is a  
> "FAQ" - if there is a way to search the archives, please let me know]:

First of all, the IPython - User forum is searchable at nabble,  
here's a link:

> When I use "pdb" I lose some of the key ipython features; tab  
> completion and syntax coloration are the ones I miss the most.  Is  
> there another debug module besides pdb, or a way to configure / run  
> the debugger within ipython, in order to get these features  
> functional at the pdb prompt?
> I am using 0.8.4 under Python 2.4.2 but looking at the release  
> notes on the subsequent versions of IPython the other night I did  
> not see anything about debugging mentioned there.  I enter the  
> debugger as follows:
> >>> import pdb
> >>> objectInstance = ... create an object ...
> >>> pdb.run('objectInstance.method()', globals(), locals())

My post prompted this response from a close colleague who works down  
the hall from me:

I think IPython already supports some degree of tab completion and  
syntax coloration while debugging in both 0.8.4 and 0.9.1.

One way to so this is to do

In [1]: %run -d myscript.py
ipdb> b somefile.py:linenumber
ipdb> c

and it stops at the breakpoint you set.  At this point a syntax  
colored source listing is printed and I'm able to use tab completion  
to print variables

ipdb> p some[TAB]      gets expanded to
ipdb> p somevariable


I've tried this and it works great!  This technique does not require  
you to touch any code (e.g. inserting pdb.set_trace() or raise an  
exception) to set a breakpoint at an arbitrary point.  Also, the -i  
option to %run allows my script to work with existing variables in  
the IPython namespace.

Best regards,

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