This message can be read easier with Org Mode.
* TL; DR: The issue
I've noticed that the =:prologue= and =:epilogue= header arguments
don't work in code blocks whose language is =latex=.
I usually take notes on the =latex= programming language (this is
different than taking notes using LaTeX) and having those header
arguments would be really helpful for me and, I suppose, other
LaTeX programmers.
The following lines of this message give more detail on the issue and
more information I gathered through experimentation so that Org Mode
developers that might be interested in fixing this issue have more
information.
* Terminology used in this message
The following two code blocks will be used to explain the issue.
#+begin_src elisp
(defun org-babel-tangle-previous-src-block-and-echo ()
"Tangles the backward nearest source code block and print the
content of the tangled file."
(save-excursion
(goto-char
(search-backward-regexp "^[[:space:]]*#\\+begin_src\\>"))
(let ((current-prefix-arg '(4)))
(call-interactively 'org-babel-tangle))
(let ((filename-tangled (shell-quote-argument (expand-file-name (cdr (assq
:tangle (nth 2 (org-babel-get-src-block-info))))))))
(shell-command-to-string (concat "cat " filename-tangled)))))
#+end_src
#+name: org-babel-tangle-previous-src-block-and-echo
#+begin_src elisp
(org-babel-tangle-previous-src-block-and-echo)
#+end_src
* Languages where these header argument work
The =:prologue= and =:epilogue= header argument work in =bash= code blocks.
#+begin_src bash :tangle ~/Downloads/main.txt :prologue "echo a" :epilogue
"echo c"
echo This is a bash code block
#+end_src
#+RESULTS:
#+begin_example
a
This is a bash code block
c
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
#!/bin/bash
echo a
echo This is a bash code block
echo c
#+end_example
They also work in =python= code blocks.
#+begin_src python :tangle ~/Downloads/main.txt :prologue "print('a')"
:epilogue "print('c')"
print('This is a python code block')
#+end_src
#+RESULTS:
#+begin_example
a
This is a python code block
c
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
print('a')
print('This is a python code block')
print('c')
#+end_example
They also work in =R= code blocks.
#+begin_src R :tangle ~/Downloads/main.txt :prologue "print('a')" :epilogue
"print('b')"
print('This is a R code block')
#+end_src
#+RESULTS:
#+begin_example
[1] "a"
[1] "This is a R code block"
[1] "b"
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
print('a')
print('This is a R code block')
print('b')
#+end_example
They also work in =maxima= code blocks.
#+begin_src maxima :tangle ~/Downloads/main.txt :prologue "print(\"a\");"
:epilogue "print(\"c\");"
print("This is a maxima code block");
#+end_src
#+RESULTS:
#+begin_example
a
This is a maxima code block
c
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
print("a");
print("This is a maxima code block");
print("c");
#+end_example
* Languages where these header arguments don't work
However, these header argument don't work in =latex= code blocks.
#+begin_src latex :tangle ~/Downloads/main.txt :prologue "a" :epilogue "c"
This is a latex code block
#+end_src
#+RESULTS:
#+begin_example
This is a latex code block
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
This is a latex code block
#+end_example
They also don't work in =cpp= code blocks
#+begin_src cpp :tangle ~/Downloads/main.txt :prologue "a" :epilogue "b"
:includes "<iostream>"
std::cout << "This is a C++ code block";
#+end_src
#+RESULTS:
#+begin_example
This is a C++ code block
#+end_example
#+call: org-babel-tangle-previous-src-block-and-echo()
#+RESULTS:
#+begin_example
#include <iostream>
int main() {
std::cout << "This is a C++ code block";
return 0;
}
#+end_example
* Additional information
In 2020, the user Tim Landscheidt created a
[[https://orgmode.org/list/ca+g3_pnrdhx0ejzw8uo7dgz+ju1b7ar_etch5mmviepkgwq...@mail.gmail.com/T/#t][thread]]
in the Org Mode
mailing list asking why these header argument don't work in SQL code
blocks. In a response to this thread, the user Tom Gillespie mentioned
that he had been working in a potential solution. If anyone knows the
progress on this, I would also apppreciate some information.
--
Greetings,
Rodrigo Morales.
