Re: Org-babel `:hlines yes` no longer working for python

[Christopher Allan Webber <cwebber@dustycloud.org>]

Eric,

Looks good to me!  It's abusing the None type's meaning a little, but
I think it's acceptable enough.  (If you think of hlines as rows that
are not rows, you can trick yourself into thinking it is perfectly
pythonic :))

 - cwebb

"Eric Schulte" <schulte.eric@gmail.com> writes:

> Hi Christopher,
>
> I'm certainly no Python expert, but I implemented your idea of
> converting "hlines" to and from "None"'s (patch below [1]), and it seems
> to work (under some definition of work).  See the following example with
> the new behavior.
>
>
> --8<---------------cut here---------------start------------->8---
> #+tblname: many-cols
> | a | b | c |
> |---+---+---|
> | d | e | f |
> |---+---+---|
> | g | h | i |
>
> #+source: echo-table
> #+begin_src python :var tab=many-cols :hlines yes
>   return tab
> #+end_src
>
> #+results: echo-table
> | a | b | c |
> |---+---+---|
> | d | e | f |
> |---+---+---|
> | g | h | i |
> --8<---------------cut here---------------end--------------->8---
>
> Please, Python people, try this out and if you like the behavior then
> I'll happily apply the patch.
>
> Best -- Eric
>
> Christopher Allan Webber <cwebber@dustycloud.org> writes:
>
>> Hey Eric,
>>
>> Thanks for the super helpful reply!
>>
>> Out of curiosity, is it likely that we will ever get hline support in
>> Python and etc?  I've been pondering how it might be done, and maybe it
>> could be like this, using a '|-' string instead of a list for the row:
>>
>> [['a', 'b', 'c'], '|-', ['d', 'e', 'f'], ['g', 'h', 'i']]
>>
>> Which would produce:
>>
>> | a | b | c |
>> |---+---+---|
>> | d | e | f |
>> | g | h | i |
>>
>> Alternately maybe the same thing could be done by abusing None:
>>
>> [['a', 'b', 'c'], None, ['d', 'e', 'f'], ['g', 'h', 'i']]
>>
>> Thoughts?
>>  - cwebb
>>
>> "Eric Schulte" <schulte.eric@gmail.com> writes:
>>
>>> Hi Christopher,
>>>
>>> Thanks for pointing this out, this is an error in the documentation,
>>> which I will update.  The code you posted should generate the error you
>>> have received.
>>>
>>> Currently the only language which can handle hlines is emacs-lisp, all
>>> other languages will result in errors like the one you pasted below.
>>> That's not to say that it wouldn't be possible to add hline handling to
>>> other languages, or to maybe do something tricky like session-based
>>> evaluation in which an `hlines' variable was pre-initialized to some
>>> value, but I digress.
>>>
>>> Note that it *is* possible to have hlines in the output, using colnames,
>>> e.g.
>>>
>>>
>>> --8<---------------cut here---------------start------------->8---
>>> #+tblname: A
>>> | a | b | c |
>>> |---+---+---|
>>> | d | e | f |
>>> | g | h | i |
>>>
>>> #+begin_src python :var tab=A :colnames yes
>>> return [[val + '*' for val in row] for row in tab]
>>> #+end_src
>>>
>>> #+results:
>>> | a  | b  | c  |
>>> |----+----+----|
>>> | d* | e* | f* |
>>> | g* | h* | i* |
>>> --8<---------------cut here---------------end--------------->8---
>>>
>>> which works because the hline, and the column names, are never made
>>> available to python, rather Babel holds onto them and then re-applies
>>> them to the source block's output.
>>>
>>> or even to have an elisp block add hlines to your results
>>>
>>>
>>> --8<---------------cut here---------------start------------->8---
>>> #+tblname: many-cols
>>> | a | b | c |
>>> |---+---+---|
>>> | d | e | f |
>>> |---+---+---|
>>> | g | h | i |
>>>
>>> #+source: echo-table
>>> #+begin_src python :var tab=many-cols
>>>   return tab
>>> #+end_src
>>>
>>> #+begin_src emacs-lisp :var table=echo-table
>>>   (butlast (apply #'append (mapcar (lambda (el) (list el 'hline)) table)))
>>> #+end_src
>>>
>>> #+results:
>>> | a | b | c |
>>> |---+---+---|
>>> | d | e | f |
>>> |---+---+---|
>>> | g | h | i |
>>> --8<---------------cut here---------------end--------------->8---
>>>
>>> Thanks for pointing this out!
>>>
>>> Best -- Eric
>>>
>>> Christopher Allan Webber <cwebber@dustycloud.org> writes:
>>>
>>>> Hello all,
>>>>
>>>> I was going through the tutorial and testing the :hlines yes feature as
>>>> described in the info manual.  Unfortunately, the example given no
>>>> longer seems to work for python:
>>>>
>>>> #+tblname: many-cols
>>>> | a | b | c |
>>>> |---+---+---|
>>>> | d | e | f |
>>>> |---+---+---|
>>>> | g | h | i |
>>>>
>>>> #+source: echo-table
>>>> #+begin_src python :var tab=many-cols :hlines yes
>>>>   return tab
>>>> #+end_src
>>>>
>>>> #+results: echo-table
>>>> | a | b | c |
>>>> | d | e | f |
>>>> | g | h | i |
>>>>
>>>> In the buffer *Org-Babel Error Output* I see:
>>>>
>>>> Traceback (most recent call last):
>>>>   File "<stdin>", line 6, in <module>
>>>>   File "<stdin>", line 3, in main
>>>> NameError: global name 'hline' is not defined
>>>>
>>>> In emacs-lisp this still seems to work though.  But I also see that in
>>>> emacs lisp hlines are represented by the hline symbol.  I'm guessing
>>>> that the python equivalent was trying to do the same thing, but no hline
>>>> variable exists in python?
>>>>
>>>> Thanks!
>>>>  - cwebb
>>>>
>>>> _______________________________________________
>>>> Emacs-orgmode mailing list
>>>> Please use `Reply All' to send replies to the list.
>>>> Emacs-orgmode@gnu.org
>>>> http://lists.gnu.org/mailman/listinfo/emacs-orgmode
>
> Footnotes: 
> [1]  
>
> diff --git a/lisp/babel/langs/ob-python.el b/lisp/babel/langs/ob-python.el
> index 2ce9e1d..29bb166 100644
> --- a/lisp/babel/langs/ob-python.el
> +++ b/lisp/babel/langs/ob-python.el
> @@ -96,7 +96,7 @@ called by `org-babel-execute-src-block'."
>  specifying a var of the same value."
>    (if (listp var)
>        (concat "[" (mapconcat #'org-babel-python-var-to-python var ", ") "]")
> -    (format "%S" var)))
> +    (if (equal var 'hline) "None" (format "%S" var))))
>  
>  (defun org-babel-python-table-or-string (results)
>    "If the results look like a list or tuple, then convert them into an
> @@ -110,7 +110,9 @@ Emacs-lisp table, otherwise return the results as a string."
>                   "\\[" "(" (replace-regexp-in-string
>                              "\\]" ")" (replace-regexp-in-string
>                                         ", " " " (replace-regexp-in-string
> -                                                 "'" "\"" results))))))
> +                                                 "'" "\""
> +						 (replace-regexp-in-string
> +						  "None" "hline" results t)))))))
>       results)))
>  
>  (defvar org-babel-python-buffers '(:default . nil))