Re: Org mode and Emacs

[Ihor Radchenko]

Richard Stallman <rms@gnu.org> writes:

>   > @latex
>   > ...
>   > @end latex
>
>   > it is actually not very intuitive that such construct implies export,
>   > but not something else.
>
> I'd like to understand this issue.  Could you please explain what
> "export" means here?  And what is the "something else", that it might
> have been?  It appears to be a distinction that doesn't exist in
> Texinfo.

You are right, Texinfo has a very narrow focus - authoring manuals in
multiple output formats. Org does a lot more.

-----

One feature of Org we are discussing here is "exporting":
https://orgmode.org/manual/Exporting.html - an ability to convert Org
documents into other textual formats.
Similar to Texinfo's raw formatter commands
(https://www.gnu.org/software/texinfo/manual/texinfo/html_node/Raw-Formatter-Commands.html),
Org provides a special markup that specifies text to be placed into
specific tex/html/odt/etc export output:

#+begin_export html
...
#+end_export
or
#+HTML: <single line>
or
@@html:<inline html>@@

See https://orgmode.org/manual/Quoting-HTML-tags.html, for example.

-----

However, Org has more features, served by other Org's markup.

-----

One of the popular features is implementing literal programming (babel).
https://orgmode.org/manual/Features-Overview.html:

    Org can manage the source code in the block delimited by
    ‘#+BEGIN_SRC’ … ‘#+END_SRC’ in several ways that can simplify
    housekeeping tasks essential to modern source code maintenance. Org
    can edit, format, extract, export, and publish source code blocks.

#+begin_src emacs-lisp :results value
  (+ 1 2)
#+end_src

#+RESULTS[b6b278abd782307b5eca9b1b761906bae5292bcc]:
: 3

Users can execute arbitrary pieces of source code in arbitrary
programming languages, get the results inline and even mix input/output
of code written in different languages:

#+name: bash-input
#+begin_src bash :results output table :var file="file.csv"
cat $file
#+end_src

#+begin_src elisp :var table=bash-input(file="table-input.csv")
(mapcar (lambda (line) (format "%S" line)) table)
#+end_src

The code evaluation results can even be used to generate exported text.
Here is a slightly edited snippet from Org manual that generates a table
of all export customizations:

#+begin_src emacs-lisp :exports results :results table :eval yes
(require 'ox)
(let ((alist org-export-options-alist))
 (let (result)
  (dolist (spec alist)
    (when (and (nth 3 spec) (symbolp (nth 3 spec))) ; has customization
      (push (list (format "~%s~" (car spec)) (format "~%s~" (nth 3 spec))) 
result)))
  (nreverse result)))
#+end_src

You can see the output in https://orgmode.org/manual/Publishing-options.html

Furthermore, users can "tangle" code from the Org document, extracting
only the appropriate source code pieces into actual code-only files.
https://orgmode.org/manual/Extracting-Source-Code.html
So, one can keep documentation and notes (with markup!) together with
the actual code, tangle the org file to produce the program, or export
the org file to produce readable notes - full literal programming
implementation.

-----

Apart from snippets of source code, Org has a markup for non-code
literal text that is not a subject of Org markup:

#+begin_example
  Some example from a text file.
#+end_example

Some people even prefer to keep snippets of source code as example
blocks as well (when a sole purpose of such source block is exporting):

#+begin_example bash
  ls $HOME
#+end_example

-----

Finally, there are dynamic blocks that can be used to generate parts of
Org file programatically from Elisp: 
https://orgmode.org/manual/Dynamic-Blocks.html

#+begin: blockname <parameters>
<automatically generated text>
#+end:

One example of built-in dynamic block is clocktable that is used by
people that record their work time using Org mode
(https://orgmode.org/manual/Clocking-Work-Time.html,
https://orgmode.org/manual/The-clock-table.html,
https://olddeuteronomy.github.io/post/org-export-clocktables/)

-----

To conclude, the common pattern for Org's block markup is

#+begin<something>
...
#+end<something>

What you proposed with @latex: ... @end is similar to dropping
<something> part. However, as you see in the above, there is a variety
of different block markups serving for entirely different purposes and
just saying @latex (or rather #+latex, if we follow the common Org
block convention) does make it intuitive whether the block is "export",
or "example" or "src" or dynamic. Furthermore, #+latex is already used
for export one-liners.

In theory, we might drop "begin" parts and get

#+src elisp
...
#+end

#+example
...
#+end

#+export html
#+end

but this is akin converting Pascal's begin/end into C's {/} - possible,
but an alternative convention is already established.

And, generally, we, in Org, try to refrain from changing syntax too much
- a number of external projects are relying upon the existing syntax.
So, making significant syntax changes should not be taken lightly.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>