Export comments as comments

6
votes

In Org-mode you can make comments and from Org-mode you can export to LaTeX but Org-mode comments are not exported to LaTeX comments. How can Org-mode be made to export Org-mode comments as LaTeX comments?

Here is an example. The following

* Test

Text before comment
# Comment
Text after comment

Text before comment
#+BEGIN_COMMENT
Comment
#+END_COMMENT
Text after comment

exports to

\section{Test}
\label{sec-1}


Text before comment
Text after comment

Text before comment

Text after comment

But I want the Org-mode comments to be exported as LaTeX comments. Thus, I want the following LaTeX output:

\section{Test}
\label{sec-1}


Text before comment
% Comment
Text after comment

Text before comment
\begin{comment}
Comment
\end{comment}
Text after comment

I am running Org-mode 7.6 in Emacs 23.3.1.

2
emacslatexcommentsorg-mode
AFAIK its not possible. But I like the idea of comments being exported as comments in the output format(those support comments in the documents) - kindahero

2 Answers

5
votes

Under the current exporter the only method I can think of that would allow you to export comments would be backend-specific. You could use something along the lines of:

#+latex: comment

or

#+begin_latex
\begin{comment}
  comment
\end{comment}
#+end_latex

However both are contrived and you would need to do the equivalent for HTML etc if you intend to export to more than one format.

There is a new exporter in development however where this should not be overly difficult to implement (comments are already identified as blocks in the parser so it would simply need a method to convert them on export).

I'm forwarding this request to the mailing list to see if this can be included.
Edit: Thread located here.

Edit: Response from the maintainer of Org-Mode

the current exporters don't allow this, but the new export engine by Nicolas makes it possible.

The plan is to merge the new export engine into Org's core before version 8.0, so please stay tuned.

3
votes

In addition to Jonathan Leech-Pepin's answer, there is a hackish way of doing it for a given exporter backend. Comments are handled in the org-export-handle-comments function, which is called by org-export-preprocess-string in org-exp.el. Each exporter backend is different, but let us consider the LaTeX backend.

If you look in the org-export-as-latex function in org-latex.el, you can find calls to org-export-preprocess-string. One of the things passed to the org-export-preprocess-string function is a parameter list, in particular it contains a :comments parameter, which in the LaTeX case is set to nil. This parameter tells the org-mode exporter what to do with comments - for the details look at the call to and implementation of org-export-handle-comments in org-exp.el. Essentially, the :comments parameter can be a format string showing how to handle the comments; if it is nil, this means no format handling so nothing is printed. If, in the org-export-as-latex function, you replace :comments nil with :comments "%% %s", then this will insert a "%" in front of whatever the comment text is upon export. So in your case 

this is text before a comment
# this is a comment
this is text after a comment

would be exported as

this is text before a comment
% this is a comment
this is text after a comment

This isn't the most convenient way of doing things, and I'm not sure of a way to specify the :comments parameter on a per-file basis. Maybe something in the thread Jonathan set up will shed some light on this subject.

Note that you may need to remove the byte-compiled org-latex.elc file in order to see your changes in org-latex.el propagate through to the export.