[Python-Dev] displayhook behavior in pdb

[Georg Brandl]

May I have a short vote on this issue:

   http://bugs.python.org/issue6903

In short, pdb (since 2.6) uses a separate displayhook in order to avoid
_ being reassigned (which screws up debugging apps that use _ as gettext).
In that displayhook, I did not add the suppression of printing None, as
it can be confusing to look at variables and get no output:

(Pdb) foo
1
(Pdb) bar
(Pdb)

(You could argue that this is what the "p" command is for though.)

Now in Python 3, where print is a function, if you call print in a loop
(e.g. to debug a list or dictionary, as it is advertised in the pdb docs
under the "alias" command), the output has the printed values interspersed
with "None"s.

Now, what is the lesser evil?

cheers,
Georg

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