From: D M German <dmg@uvic.ca>
To: emacs-orgmode@gnu.org
Subject: evaluation of perl in babel
Date: Sun, 24 Feb 2013 13:08:39 -0800 [thread overview]
Message-ID: <87hal1whbc.fsf@mn.cs.uvic.ca> (raw)
Hi Everybody,
I looked a bit more onto the way that perl is evaluated. I know the
support of perl is minor. I understand that, so please, don't see this
message as a complaint, so this is more for discussion and potential
improvements of the Perl support in Babel.
One of the things I have noticed is that the way that Babel handles the
results coming from the code is not the best.
Let me elaborate:
At the bottom you will find a set of test that stress the different
:results types.
There are some bugs. For example, the interpretation of :results table,
vector and list.
But I think the main problem comes from the way that Babel expects the
result. In Babel, and except for :results output, the last expression in
perl is considered the input to the results. This is implementing by
saving the last expression into a variable, and printing each value
separated by a "\n" (including the last). So basically, org takes the
last expression, and outputs them to the babel input file one per line.
This places some constraints. First, it is not currently capable of
dealing with two dimensional arrays. Second, it makes it hard to create
complex output (such as HTML or LaTeX), and third, it is hard to debug
without first printing the value of the array (this output would be lost
during the evaluation, so it would have be debugged outside org).
I feel that a better approach is to use std output as the default input
to any of these :results types, and then try to parse them into the
corresponding :results types. This will allow the creation of HTML and
LaTeX from perl (which the current implementation does not allow).
So recapitulating, my suggestion is that perl should use STDOUT as the
output of the snippet in any :results type, rather than the result of
the last expression.
I know this will break backwards compatibility. One solution is to keep
the current src perl and add a new perl_stdout mode (or something like
that) that implements this.
--dmg
----------------------------------------------------------------------
#+begin_src perl :results output
print "Test\n";
(1, 2)
#+end_src
#+RESULTS:
: Test
#+name: t_output_raw
#+begin_src perl :results raw
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_raw
1
2
#+name: t_output_table
#+begin_src perl :results table
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_table
| 1\n2\n |
#+name: t_output_vector
#+begin_src perl :results vector
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_vector
| 1\n2\n |
#+name: t_output_list
#+begin_src perl :results list
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_list
#+begin_example
- 1
2
#+end_example
#+name: t_output_org
#+begin_src perl :results org
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_org
#+BEGIN_SRC org
1
2
#+END_SRC
#+name: t_output_html
#+begin_src perl :results html
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_html
#+BEGIN_HTML
1
2
#+END_HTML
#+name: t_output_latex
#+begin_src perl :results latex
print "Test\n";
(1, 2)
#+end_src
#+RESULTS: t_output_latex
#+BEGIN_LaTeX
1
2
#+END_LaTeX
----------------------------------------------------------------------
--
Daniel M. German "I see no good reason why the
views given in this volume
should shock the religious
Charles Darwin -> feelings of anyone."
http://turingmachine.org/
http://silvernegative.com/
dmg (at) uvic (dot) ca
replace (at) with @ and (dot) with .
next reply other threads:[~2013-02-24 21:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-24 21:08 D M German [this message]
2013-02-24 21:25 ` evaluation of perl in babel dmg
2013-02-24 22:09 ` Achim Gratz
2013-02-25 9:54 ` D M German
2013-02-25 9:57 ` dmg
2013-02-25 14:11 ` Eric Schulte
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87hal1whbc.fsf@mn.cs.uvic.ca \
--to=dmg@uvic.ca \
--cc=emacs-orgmode@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.