Is it possible to add custom transformations for files before compilation?

[mainrs]

Similar to latexmk. I have some .txt files that I want to convert to latex before compiling it with tectonic.

[Neved4]

Hey @mainrs! How do you use latexmk to convert .txt files? Could you explain me a bit more about your use case?

[harrymander]

Not sure of @mainrs's exact use case, but I use latexmk similarly for generating graphics from scripts, e.g. converting SVG to PDF with Inkscape or generating PGF plots with pyplot. I have just recently discovered this project and am certainly interested in using it since it seems much simpler than latexmk!

Here is a simple example using pyplot:

example.txt

\documentclass[a4paper]{article}

\usepackage{pgfplots}

\begin{document}

Hello, World

\input{plot.pgf}

\end{document}

plot.py

import sys
import matplotlib.pyplot as plt


if __name__ == '__main__':
    path = sys.argv[1]
    plt.figure()
    plt.plot(range(50))
    plt.savefig(path, format='pgf')

latexmkrc (perl)

@default_files = ('example.tex');
$pdf_mode = 1;
$pdflatex = 'pdflatex --shell-escape -interaction=batchmode -synctex=1 %O %S';
$cleanup_includes_generated = 1;
$cleanup_includes_cusdep_generated = 1;

add_cus_dep("py", "pgf", 0, "py2pgf");
sub py2pgf {
    system("python3 $_[0].py $_[0].pgf");
}

latexmk will attempt to compile example.tex with pdflatex and get an error saying that plot.pgf is missing. It will then look for a corresponding plot.py to generate the PGF file before running pdflatex again.

Alternatively, you could generate the dependencies with make and incorporate latexmk into it. I suppose you could also incorporate tectonic into a Makefile as well.