Problem with bash arrays from list-valued org-babel :var assignments?

Problem with bash arrays from list-valued org-babel :var assignments?

[Keith Amidon]

With current org-mode, when I try to execute the following org-babel
block:

#+begin_src bash :var lst='(1 2 3 4 5 6 7)
printf "%s\n" "${lst[*]}"
#+end_src

I get result and the following error in the minibuffer:

   Wrong type argument: listp, 1

This, on the other hand works fine:

#+begin_src emacs-lisp :var lst='(1 2 3 4 5 6 7)
lst
#+end_src

In investigating this, I looked into the code for how bash variables
are set from the org variables and found this code in ob-shell that I
don't really understand:

(defun org-babel--variable-assignments:bash (varname values &optional sep hline)
  "Represents the parameters as useful Bash shell variables."
  (if (listp values)
      (if (and (listp (car values)) (= 1 (length (car values))))
	  (org-babel--variable-assignments:bash_array varname values sep hline)
	(org-babel--variable-assignments:bash_assoc varname values sep hline))
    (org-babel--variable-assignments:sh-generic varname values sep hline)))

I *think* that the org-babel--variable-assignments:bash_assoc function
is supposed to allow initializing bash arrays with arbitrary key/value
mappings when each element of the list is itself a list where the first
element of the sublist is the key of the mapping and the remaining
elements form the value, whereas the org-babel--variable-
assignments:bash_array function is supposed to create integer-indexed
bash arrays for simple lists.

However, if that is the case, the logic for picking between them
doesn't work as I would expect, since a simple list like the example at
the beginning of this email, '(1 2 3 4 5 6 7), will will fail the test
(listp (car values)) and result in the bash_assoc version being called
when the list is not of the correct form for that function.

The following version of the function that replaces the current test
with a simpler one seems to do what I think the expected behavior
should be for both types of lists, but it isn't clear to me whether the
current code is trying to support some other use cases that I don't
understand:

(defun org-babel--variable-assignments:bash (varname values &optional sep hline)
  "Represents the parameters as useful Bash shell variables."
  (if (listp values)
      (if (not (listp (car values)))
	  (org-babel--variable-assignments:bash_array varname values sep hline)
	(org-babel--variable-assignments:bash_assoc varname values sep hline))
    (org-babel--variable-assignments:sh-generic varname values sep hline)))

In any case, it seems like the simple example at the beginning of this
message should work. Is this a bug or am I missing something?

          Thanks, Keith

Re: Problem with bash arrays from list-valued org-babel :var assignments?

[Neil Jerram]

On 09/06/17 05:56, Keith Amidon wrote:
> With current org-mode, when I try to execute the following org-babel
> block:
>
> #+begin_src bash :var lst='(1 2 3 4 5 6 7)
> printf "%s\n" "${lst[*]}"
> #+end_src
>
> I get result and the following error in the minibuffer:
>
>     Wrong type argument: listp, 1
>
> This, on the other hand works fine:
>
> #+begin_src emacs-lisp :var lst='(1 2 3 4 5 6 7)
> lst
> #+end_src
>
> In investigating this, I looked into the code for how bash variables
> are set from the org variables and found this code in ob-shell that I
> don't really understand:
>
> (defun org-babel--variable-assignments:bash (varname values &optional sep hline)
>    "Represents the parameters as useful Bash shell variables."
>    (if (listp values)
>        (if (and (listp (car values)) (= 1 (length (car values))))
> 	  (org-babel--variable-assignments:bash_array varname values sep hline)
> 	(org-babel--variable-assignments:bash_assoc varname values sep hline))
>      (org-babel--variable-assignments:sh-generic varname values sep hline)))

Based on that code, I'd expect this to work, and it does:

#+begin_src bash :var lst='((1) (2) (3) (4) (5) (6) (7))
printf "%s\n" "${lst[*]}"
#+end_src

#+RESULTS:
: 1 2 3 4 5 6 7

But I agree that it would still be nice if the more intuitive form that 
you mentioned also worked.

Regards,
      Neil

Re: Problem with bash arrays from list-valued org-babel :var assignments?

[Nicolas Goaziou]

Hello,

Keith Amidon <camalot@picnicpark.org> writes:

> With current org-mode, when I try to execute the following org-babel
> block:
>
> #+begin_src bash :var lst='(1 2 3 4 5 6 7)
> printf "%s\n" "${lst[*]}"
> #+end_src
>
>
> I get result and the following error in the minibuffer:
>
>    Wrong type argument: listp, 1

Fixed. Thank you.

Regards,

-- 
Nicolas Goaziou