How to return an org mode table with headings and hline from Ruby

Question

I have the same question as this question except that I don't see how to do so other than in elisp. I am using Ruby, but I suppose the question applies to other languages as well. If I return an array of arrays as the value result of some code, I want to have it formatted as a table headed with the column names.

Here is the solution to what I want in elisp:

#+BEGIN_SRC emacs-lisp :results value table
  '(("First" "Second")
    hline
    (a b) (c d))
#+END_SRC

#+RESULTS:
| First | Second |
|-------+--------|
| a     | b      |
| c     | d      |

But I've tried variants of this in Ruby with no luck. For example:

#+BEGIN_SRC ruby :results value table
    [ [ 'First', 'Second'],
      :hline,
      [ :a, :b ],
      [ :c, :d ]
    ]
#+END_SRC

#+RESULTS:
| (First Second) | :hline | (:a :b) | (:c :d) |

Which is not what I want. So, what is the incantation to use here?

Answer 1

For others who may want to know the answer, I finally figured it out. In the case of ruby, you should insert a nil where you want the hline to appear. Org represents a table as an array of arrays.

Here is what I used to discover the right incantation for ruby:

#+NAME: test
|  Ref | Value |
|------+-------|
| 0001 | blue  |
| 0002 | red   |

#+HEADER: :colnames no
#+HEADER: :hlines yes
#+HEADER: :results value raw
#+BEGIN_SRC ruby :var tab=test
 tab
#+END_SRC

#+RESULTS:
[["Ref", "Value"], nil, [1, "blue"], [2, "red"]]

So to generate a table with column headers and an hline, just produce an array of arrays with the first sub-array an array of headings and the second element a nil instead of a sub-array.

Just use a SRC block for your favorite language to discover how it represents headings.