[Tex/LaTex] Use compile LaTeX to HTML with subfiles

Question

I've got a rather large tex project I'd like to turn into one or many linked html files. However neither of my go-to converters, pandoc and latex2html, seem to support recursive compilation.

Is there a compiler flag for one of them that I'm missing? If not, is there a converter that supports what I'm trying to do, or do I just have to copy and paste everything into one absurdly long document?

EDIT:

To be clear, I have a file main.tex with the subfiles package. I have several other files, i.tex etc, of the form:

\documentclass[/path/to/files]{subfiles}
\begin{document}
Some words
\end{document}

How do I include all of them in my final document, either as content in some main.html or separate i.html files linked in to main.html, without doing the hard work by hand?

Answer 1

tex4ht support this. It needs a simple configuration file, subfiles.4ht to support multiple subfiles:

\def\:tempa#1{%
  \ifcsname subfiles@end\endcsname
  \else
    \subfiles@saveEndTo\subfiles@end
  \fi
  \let\choose:begin\@secondoftwo
  \expandafter\def\csname end \endcsname##1{%
    \romannumeral
    \subfiles@StrIfEqTF{##1}{document}{%
      \z@
      \subfiles@restoreEndFrom\subfiles@end
      #1%
    }{%
      \expandafter\expandafter\expandafter\z@\subfiles@end{##1}%
    }%
  }%
}

\HLet\subfiles@renewEndDocument\:tempa
\Hinput{subfiles}
\endinput

It disables \end{document} in the included subfile, because it would close the document otherwise.

Simple example.

Main file sample.tex:

\documentclass{article}

\usepackage{subfiles}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\begin{document}
\title{Subfile example}
\maketitle
\tableofcontents
\subfile{subfile1.tex}
\end{document}

Included file subfile1.tex:

\documentclass[sample.tex]{subfiles}
\begin{document}
\section{Hello world}
Some words

Příliš žluťoučký kůň
\end{document}

You can compile the document using command

make4ht -u sample.tex

And this is the result: