Re: [PATCH] (Tiny) Tweak Python session null return value

[John Kitchin]

I think None is correct. If you don't specify a return value in Python, then a function returns None. I would expect that to happen in a Python block too.

John

-----------------------------------
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

On Mon, Feb 17, 2020 at 11:25 AM Jack Kamm <address@hidden> wrote:

Hi,

Below is a very small patch to Python session blocks, to make them
return a blank result (empty string) instead of None when there is no
return value.

Normally I would push this myself, but since we are so close to 9.4, I
thought it prudent to mail a patch and let the maintainers handle it. It
would be nice to include in 9.4, but not a big deal if I've missed the
window.

Now for an explanation of the patch: 9.4 changes Python session blocks
to fix several bugs and improve robustness overall [0]. However, there
is a cost to these fixes, which is that the session blocks can only
return a result when it is a top-level _expression_ on the last line of
the block. If the last line is not a top-level _expression_, the block
would previously print "None". However, after some testing, I think this
is a little counter-intuitive, and it would be better if it returned a
blank (empty) result instead of "None".

[0] https://lists.gnu.org/archive/html/emacs-orgmode/2020-01/msg00190.html

Best,
Jack