Re: [BUG] ob-R.el: extra empty data.frame columns generated from plain lists after recent change [9.6 (release_9.6-3-ga4d38e @ /usr/share/emacs/30.0.50/lisp/org/)]

[Ihor Radchenko <yantar92@posteo.net>]

Jeremie Juste <jeremiejuste@gmail.com> writes:

> Many thanks for the insights. I confess that I have never transferred
> list from org to R before. I've always use tables and as far as I
> understand they works fine in 9.6.
>
> So assuming this list
>
> #+name: alist 
> - first item
> - second item
> - third item
>   - 3.1 item
> - fourth item
>
>
> before c72d5ee84 we could do something like 
>
> #+begin_src R :var list=alist
>   list
> #+end_src
>
> #+RESULTS:
> | first item  |                        |
> | second item |                        |
> | third item  | (unordered (3.1 item)) |
> | fourth item |                        |

And it was a bug that the ob-core patch fixed.
Unfortunately, a number of babel backends also developed workarounds
meanwhile.

For the context, the ground truth is Org manual:

16.4 Environment of a Code Block

    list
         A simple named list.
    
              #+NAME: example-list
              - simple
                - not
                - nested
              - list
    
              #+BEGIN_SRC emacs-lisp :var x=example-list
                (print x)
              #+END_SRC
    
              #+RESULTS:
              | simple | list |
    
         Note that only the top level list items are passed along.  Nested
         list items are ignored.

> and after we end up with 
>
>
> #+begin_src R :var list=alist
>   list
> #+end_src
>
> #+RESULTS:
> | first item | second item | third item | fourth item |   |   |   |   |   |   |
>
> Here I'm on uncharted territory. We could go with 
> 1.
> | first item | second item | third item | fourth item |
>
> or be closer to the version 9.5 with
> 2. 
> | first item  | 
> | second item | 
> | third item  | 
> | fourth item | 
>
> However I'm still tempted to choose the second option to break as little
> workflow as possible.
>
> If we go in this direction the solution of Chuck works fine. Many thanks
> for the suggestions.

I also like the second option as **printing** more, but it is _not_ what
we have in the manual.

Note that the origin of the issue is in how list=alist is assigned.

Before the problematic commit, we had awkward situation when
alist=(("first item") ("second item") ...)

I changed things to
alist=("first item" "second item" ...)
which makes a lot more sense when passed as variable value.

Now, printing:

ob-core prints lists as a special case of tables.
Since ("first item" "second item" ...) is a row vector, we get
| first item | second item | ... |

changing row vectors to be printed as column vectors is easy, but I am
afraid about non-trivial breakage.


Hope the above clarifies about what happened and why I changes things
like I did.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
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