Re: [O] Problem with python session

[John Kitchin]

I am not sure it makes sense to change anything for this. There is
different behavior with scripts and the interpreter independently of
org-mode, e.g. with python -i:

>>> for i in range(3):
...     print(i)
... i
  File "<stdin>", line 3
    i
    ^
SyntaxError: invalid syntax

Vanilla python sessions are kind of maddening. These seemingly identical blocks
are different, i.e. one works and one doesn't! Spoiler alert, they are not 
identical.

#+BEGIN_SRC python :results output org drawer :session
for i in range(3):
    for j in range(3):

        pass

    print(i)
#+END_SRC

#+RESULTS:
:RESULTS:

...   File "<stdin>", line 3
    
    ^
IndentationError: expected an indented block
File "<stdin>", line 1
    pass
    ^
IndentationError: unexpected indent
>>>   File "<stdin>", line 1
    print(i)
    ^
IndentationError: unexpected indent
:END:

This block which works has one space at the beginning of the blank lines.

#+BEGIN_SRC python :results output org drawer :session
for i in range(3):
    for j in range(3):
 
        pass
 
    print(i)
#+END_SRC

#+RESULTS:
:RESULTS:

... ... ... ... ... 0
1
2
:END:

This kind of error would be hard to reliably fix IMHO since it would
rely on replacing blank lines with at least a space, and adding a blank
line after indentation changes, except they can not be empty, they need
at least a space in them. It is not clear that is a good idea. Maybe a
test that replaces "\n" with "\n \n" might clear it up, but might also
add a bunch of the ... >>> characters in the output? 

This is not an issue with python scripts or ipython, however.





Nicolas Goaziou writes:

> Hello,
>
> William Henney <address@hidden> writes:
>
>> I can reproduce your problem.  This is (arguably) a bug in ob-python when
>> using the vanilla python interpreter together with the :session argument.
>> You can work around it by putting a blank line after the for-loop in your
>> second code block.
>>
>> I say that it is arguable that this is a bug or not since you would have
>> exactly the same error if you were to literally type your code block in at
>> the python interactive prompt.  That is, you have to give a second newline
>> in order to close the loop and return to the top-level prompt.  However, it
>> is admittedly confusing to have different behavior with and without the
>> ":session" argument.
>
> Thank you for the analysis. Would you have a suggestion on how to
> improve the situation?
>
> Regards,


-- 
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu