org-hacks.org: Add https://github.com/alphapapa/unpackaged.el#ensure-blank-lines...

[worg.git] / org-dependencies.org

#+TODO: TODO STARTED | DONE
#+OPTIONS: toc:t

* Dependencies

#+index: Dependencies

Certain parts of org-mode have dependencies on external packages. This
file documents these dependencies. Many sections are placeholders,
waiting for input. If you can, please contribute. If you think that
another section should be added, please add it and fill it out. Also,
if you spot any mistakes, omissions or superfluities, please fix
them. If you have an account, you can clone the Worg tree and make the
additions/fixes (see [[https://orgmode.org/worg/worg-git.html]] for more
information), but if you don't or don't want to do it yourself, that's
fine too: a note to the [[mailto:emacs-orgmode@gnu.org][orgmode mailing list]] will also do
the job. Thanks!

Version: Org-mode version 7.8.03 (release_7.8.03.346.g1915.dirty)

** TODO Exporting in general.

Anything here?

** STARTED LaTeX export.

The LaTeX class is selected using the construct

: #+LaTeX_CLASS: <class>

org-latex predefines the treatment of the following LaTeX classes article,
report, book, beamer - or you can roll your own. And you can, of course,
customize the treatment to your heart's content.  This assumes a standard
LaTeX install.

On Linux/Mac OSX/BSD, the TeXlive distribution is recommended.  On Windows,
most people prefer MikTeX.

** Where to get packages

The best way to get these packages is by using the package manager that
comes with your operating system. These generally contain many useful LaTeX
packages.

If that is not possible, then you can get individual LaTeX packages from
the CTAN sites (see [[http://www.tex.ac.uk/cgi-bin/texfaq2html?label=archives][CTAN archives]] for more information), but the
installation process is less straightforward (but more portable): generally
speaking, a LaTeX package comes in two files: a .ins file and a .dtx file
(usually packed in a zip or tgz archive). Processing the .ins file through
latex separates out the code from the .dtx file and produces the pieces
that need to be installed on your system, but then it is up to you to
figure out where to copy these files on your system for TeX and friends to
find them. The command ``kpsewhich'' is useful here: learn to use it well.

Processing the .dtx file directly through latex produces the
documentation of the package:

    - latex foo.ins -> foo.sty, etc.
    - pdflatex foo.dtx -> foo.pdf

Those too can be installed in standard places, so that the command ``texdoc''
can find and display them.

Many questions are answered by the [[http://www.tex.ac.uk/cgi-bin/texfaq2html?introduction=yes][TeX FAQ]] site, although the search
capability is fairly primitive by today's standards: you will have to
search a bit more diligently.

*** DONE Standard classes: article, book, report, beamer

The LaTeX packages included by default are as follows:

| LaTeX package | Ubuntu container package  | Options | Comments                          |
|---------------+---------------------------+---------+-----------------------------------|
| inputenc      | texlive-latex-base        | utf8    |                                   |
| fontenc       | texlive-latex-base        | T1      |                                   |
| fixltx2e      | texlive-latex-base        |         | Various LaTeX fixes - fix-cm too? |
| graphicx      | texlive-latex-base        |         |                                   |
| longtable     | texlive-latex-base        |         |                                   |
| float         | texlive-latex-recommended |         | floating environments             |
| wrapfig       | texlive-latex-extra       |         | text wrapping around figures      |
| soul          | texlive-latex-extra       |         | Underline/strike through          |
| textcomp      | texlive-latex-base        |         | Misc text symbols                 |
| marvosym      | texlive-fonts-recommended |         | Euro symbol                       |
| wasysym       | texlive-fonts-recommended |         | Misc symbols                      |
| latexsym      | texlive-latex-base        |         | Math symbols                      |
| amssymb       | texlive-base              |         | Math symbols                      |
| hyperref      | texlive-latex-base        |         |                                   |

*** STARTED Code blocks
By default, code blocks are rendered as verbatim blocks on export -
this setting does not have any additional dependencies.  However,
LaTeX provides a couple of packages that produce output that most
people prefer: one is the ``listings'' package and the other is the
``minted'' package.  Which package is used is determined by the value
of the variable org-latex-listings: nil means the default
verbatim block export, 'minted means the minted package and any
non-nil value other than 'minted means the listings package.


**** Listings package

On Ubuntu, listings.sty is part of the texlive-latex-recommended package.
If you want to use color names, you will need color.sty, part of the
texlive-latex-base Ubuntu package.

The setup is straightforward - add this to your .emacs (or equivalent):

#+BEGIN_SRC emacs-lisp :exports code :results none
   (require 'ox-latex)

   (setq org-latex-listings t)
   (add-to-list 'org-latex-packages-alist '("" "listings"))
   (add-to-list 'org-latex-packages-alist '("" "color"))
#+END_SRC

**** Minted package

Minted is an externally provided package. It consists of a couple of
pieces: minted.sty provides the latex interface. It calls on an
external python program called ``pygmentize'' to do the heavy
lifting. See the [[*Special%20note%20about%20TeX%20and%20external%20programs][Special note about TeX and external programs]].

The minted.sty package can be downloaded from CTAN:

  http://mirror.ctan.org/macros/latex/contrib/minted.zip

See [[*Where%20to%20get%20packages][Where to get packages]] for instructions.

The pygmentize library can be downloaded from

  http://pygments.org

and there is documentation about installation as well.

To use minted with org, there is no setup involved other than
setting org-latex-listings to minted:

#+BEGIN_SRC emacs-lisp
   (setq org-latex-listings 'minted)
#+END_SRC

The minted.sty package is automatically added to the output .tex
file.

**** Special note about TeX and external programs

Some packages (e.g. minted.sty) try to execute an external program in
order to accomplish their goal, by using the so-called \textbackslash =write18=
construct. This is normally *prohibited* for security reasons. There
are various ways to allow it, some more convenient or more secure than
others.

If you use e.g. pdflatex from the command line, then in order to allow
such external program execution, you just add the command-line option
--shell-escape:

#+BEGIN_SRC sh
  pdflatex --shell-escape myfile.tex
#+END_SRC

If you are exporting from org to latex and processing directly to pdf,
then this mechanism can be implemented by customizing
org-latex-to-pdf-process, which is a list of commands to execute.  By
default, this list consists of three repetitions of a basic pdflatex
command, so you need to modify each of the three instances to add the
--shell-escape option. NB: the three repetitions are supposed to
ensure that all the references in a basic tex file will be
resolved. This heuristic works most of the time, but not all the time.

A more flexible approach consists of using the texi2dvi program, which
analyzes logs in order to figure out what it needs to do: if the log
contains complaints about undefined references, then texi2dvi will
call pdflatex (or whatever) again in order to resolve them. In
addition, texi2dvi is smart enough to invoke bibtex and
texindex/makeindex if necessary, something that you would have to
specify explicitly if you don't use texi2dvi. So why not use texi2dvi
by default?

One problem is that the currently [2012-02-21 Tue] available version
on most OSes suffers from an obscure egrep bug, one that causes
mysterious failures (unless you've seen the error before).

If you want to take matters into your own hands, by all means fix
texi2dvi in your setup and use it. The bug is on line 1713 - change
it from 

#+BEGIN_SRC sh
  echo "$command_line_filename" | $EGREP '^(/|[A-z]:/)' >&6 \
#+END_SRC

to

#+BEGIN_SRC sh
  echo "$command_line_filename" | $EGREP '^(/|[A-Za-z]:/)' >&6 \
#+END_SRC

The observant reader will note that the regexps are *not* equivalent,
but in practice that does not matter unless you have DOS drives named
with one of the characters in the ASCII charset that falls between
``Z'' and ``a''. If you do have drives named like this, you have more
immediate problems than getting org to work on your machine.

OK, let's assume you fixed your version of texi2dvi. How do you use
it? Just set

#+BEGIN_SRC emacs-lisp
  (setq org-latex-to-pdf-process '("texi2dvi --pdf %f" ))
#+END_SRC

Wait a minute: where do I put the --shell-escape option? That's the
second problem with texi2dvi. The best way I know to have texi2dvi
call pdflatex with the --shell-escape option is to define the env
variable

#+BEGIN_SRC sh
  PDFLATEX="pdflatex --shell-escape"
  export PDFLATEX
#+END_SRC

in your .profile, .bash_profile, .login or whatever init file your
login shell uses. Emacs will inherit this env variable and its value
and when org invokes texi2dvi (which used $PDFLATEX internally),
everything will work out. Another method (which is probably preferred
by the security-conscious) is to leave it undefined. If pdflatex does
not end up executing external programs, there is no problem. If it does,
you'll get an error, so you say

#+BEGIN_SRC emacs-lisp
  (setenv "PDFLATEX" "pdflatex --shell-escape")
#+END_SRC

to your emacs and everything will work as before. The only problem is
that the error is usually well hidden, so you'll have to dig to find it.
For example, trying to export this file to PDF with PDFLATEX undefined,
gives me the following error:

  =PDF file /home/nick/src/emacs/org/Worg/org-dependencies.pdf was not produced=

But if I export to latex and try it from the command line:

#+BEGIN_SRC sh
pdflatex org-dependencies.tex
#+END_SRC

the error is clear:

  =! Package minted Error: You must invoke LaTeX with the -shell-escape flag.=

Achim Gratz suggested a different, less intrusive method on the mailing list:
#+BEGIN_QUOTE
> 2) put this in ~/.profile:
>    PDFLATEX="pdflatex --shell-escape"
>    export PDFLATEX

You might not want to do this either.  The canonical way to set the
environment for a single command is to define it right there with the
invocation of the command.

 (setq org-latex-to-pdf-process '("PDFLATEX=\"pdflatex --shell-escape\" texi2dvi -p %f"))

Or if your system still had the locale bug even

 (setq org-latex-to-pdf-process '("LC_ALL=C PDFLATEX=\"pdflatex --shell-escape\" texi2dvi -p %f"))

#+END_QUOTE

*** STARTED Symbols

LaTeX syntax can be used to introduce many special symbols into a
document (e.g. mathematical symbols). Most of these symbols are
defined by basic LaTeX, but some require the presence of extra
packages.

| LaTeX macro | Rendered Symbol (approx) | LaTeX package | Ubuntu container package  |
|-------------+--------------------------+---------------+---------------------------|
| =\EUR=      | \EUR                     | marvosym      | texlive-fonts-recommended |
| =\euro=     | \euro                    | eurosym       | texlive-fonts-recommended |

Note that marvosym is now included as part of the default setup so you do
not need to include the package explicitly.

** STARTED PDF export.

PDF export goes through LaTeX export first, so all the LaTeX dependencies
apply here as well.

Certain PDF viewers have been reported to produce more or less unreadable
files if Adobe Type3 fonts are used in the document.  Evince has been
identified as one of those. One way around this problem is to not use Type3
fonts. Another is to use a viewer that does not mistreat Type 3 fonts.

You can find more information about this problem in the TeX FAQ:

To find out whether a document uses Type3 fonts, open it with Acrobat
Reader/Evince, select Properties from the File menu and then select the
Fonts tab; alternatively, use the pdffonts program (part of the xpdf-reader
package) from the command line.

It is probably impossible to get rid of Type3 fonts completely
(particularly if you are using special symbols or languages that don't use
the Latin alphabet: in such cases, font availability is more limited and
you just might not be able to find Type1 fonts to do the job).

For standard latin-alphabet languages that use the Computer Modern fonts
(including small variations e.g. Polish and Czech), you *can* find Type1
versions: (XXX-needs fixing) the texlive-fonts-extra package (on
Ubuntu/Debian) e.g. includes the AMS CM fonts which work well.  Similar
packages exist for other Linux distributions and probably for other
operating systems as well.

| Type1 font      | LaTeX package | Ubuntu container package |
|-----------------+---------------+--------------------------|
| Computer Modern | amsfonts      | texlive-base             |
| Euler           |               |                          |

(/XXX-needs fixing)

** TODO DocBook export.

** STARTED HTML export.

*** STARTED Exporting LaTeX fragments as images.

LaTeX fragments can be exported as images for inclusion into HTML
documents. For example, complicated mathematical expressions can be
dealt with this way. This is done by creating a LaTeX file that
contains the fragment, processing it through LaTeX to produce a DVI
file and then processing it through dvipng. So, in addition to LaTeX,
you will need dvipng: on Ubuntu, this is available in the "dvipng"
package.

The LaTeX file contains a somewhat different list of LaTeX packages.  Note
that this is the default list, determined by the value of the variable
``org-format-latex-header''.

| LaTeX package | Ubuntu container package | Options  |
|---------------+--------------------------+----------|
| amssymb       | texlive-base             |          |
| color         | texlive-latex-base       | usenames |
| amsmath       | texlive-latex-base       |          |
| latexsym      | texlive-latex-base       |          |
| eucal         | texlive-base             | mathscr  |

** TODO org-plot

** STARTED org-babel

For evaluating code blocks in some language, you need at the very
least, the interpreter for the language.