Ah, so the mystery is solved :)

Thanks.

Something needs to be wrong on my side. I've noticed, that even the hybrid option doesn't work with the markdown environment. Both with make4ht and LuaLaTeX. But, if I use the \markdownSetup command to make these options global, they work.

So the following example works, but not if I remove the \markdownSetup command:

%%%%%%%%%%%%%%%%%%%
\documentclass{book}
\usepackage{lmodern}
\usepackage{booktabs}
% Load the Markdown package and set its options.
\usepackage[
]{markdown}
\markdownSetup{
hybrid,html
}
\begin{document}

\begin{markdown}[hybrid]
hello \TeX, what's goind on?
\end{markdown}

\begin{markdown}[html,hybrid]
Here is some <b>HTML code</b> mixed with Markdown. In \TeX, the HTML code
will be silently ignored, whereas in \TeX 4ht, the HTML code will be passed
through to the output:

<table border="1">
<tr>
<td>Emil</td>
<td>Tobias</td>
<td>Linus</td>
</tr>
<tr>
<td>16</td>
<td>14</td>
<td>10</td>
</tr>
</table>
\end{markdown}
\end{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%

I used the default installation of the Markdown package in my TeX Live, it says "Package: markdown 2023-04-27 v2.23.0-0-g0b22f91 markdown renderer", so it seems pretty old, but probably correct, as it is the same as the latest release on CTAN. I guess this version doesn't support inline HTML?

I've missed that the example is meant for PDFLaTeX, so I used LuaLaTeX, which led to the missing accented characters. They are here when I switch engines.

Yes, exactly. I see HTML tags in both PDF and HTML outputs.

(file #530, file #531)

BTW is it OK that the last code snippet in the TeX file, which contains HTML tags, is inserted verbatim in the output? I thought that HTML tags should be passed to the HTML output without escaping.

Thanks. Your newly uploaded file fancyvrb.4ht seems to work fine, see also the attached screenshot of the output for the example document of the Markdown package.

(file #528)

With the Docker image `texlive/texlive:latest` from the last Sunday, I am seeing the following errors [1] during the compilation of the example document for make4ht [2]:

$ make4ht --shell-escape latex-tex4ht.tex fn-in
[STATUS] make4ht: Conversion started
[STATUS] make4ht: Input file: latex-tex4ht.tex
[ERROR] htlatex: Compilation errors in the htlatex run
[ERROR] htlatex: Filename Line Message
[ERROR] htlatex: /usr/local/texlive/2023/texmf-dist/tex/generic/tex4ht/fancyvrb.4ht 97 Illegal parameter number in definition of \FVC@Verb.
[ERROR] htlatex: /usr/local/texlive/2023/texmf-dist/tex/generic/tex4ht/fancyvrb.4ht 98 Illegal parameter number in definition of \FVC@Verb.
[ERROR] htlatex: /usr/local/texlive/2023/texmf-dist/tex/generic/tex4ht/fancyvrb.4ht 98 Illegal parameter number in definition of \FVC@Verb.

[1]: https://github.com/Witiko/markdown/actions/runs/7459249826/job/20294884745
[2]: https://github.com/Witiko/markdown/blob/main/examples/latex-pdftex.tex

I have not yet had the time to investigate the cause but it seems possibly related to the fix from this ticket.

Hi Michal,

thanks for the speedy response. Your workaround works for me.

Adding your config into a file `example.cfg` and running the commands `make4ht -c example.cfg example-01.tex` and `make4ht -c example.cfg example-02.tex` produces two HTML files with the following diff:

```
7,8c7,8
< <link href='example-01.css' rel='stylesheet' type='text/css' />
< <meta content='example-01.tex' name='src' />
---

> <link href='example-02.css' rel='stylesheet' type='text/css' />
> <meta content='example-02.tex' name='src' />

```

In other words, both the `Verbatim` LaTeX environment and the `\VerbatimInput` LaTeX command produce the same HTML output and it is the correct one:

```
<pre class='fancyvrb' id='fancyvrb1'><a id='x1-3r1'></a><span class='cmtt-10'>foo</span>
<a id='x1-5r2'></a><span class='cmtt-10'>bar</span>
<a id='x1-7r3'></a><span class='cmtt-10'>baz</span></pre>
```

From where I stand, your workaround seems as a good candidate for adding to the TeX4ht sources.

I am having an issue with undesirable double-spacing with the `fancyvrb` LaTeX package and the TeX4ht typesetting system. Below, I outline the steps to reproduce the problem and show the expected and actual outcome.

### Steps to reproduce

I create the following LaTeX document in a file named `example-01.tex`:

```
\documentclass{article}
\usepackage{fancyvrb}
\usepackage{hyperref}
\begin{document}
\begin{Verbatim}
foo
bar
baz
\end{Verbatim}
\end{document}
```

I also create the following LaTeX document in a file named `example-02.tex`:

```
\documentclass{article}
\begin{filecontents}[overwrite, nosearch, noheader]{example.foo}
foo
bar
baz
\end{filecontents}
\usepackage{fancyvrb}
\usepackage{hyperref}
\begin{document}
\VerbatimInput{example.foo}
\end{document}
```

Then, I typeset both documents in TeX4ht using the `make4ht example-01.tex` and `make4ht example-02.tex` commands.

### Expected outcome

Identical HTML documents in files `example-01.html` and `example-02.html` are produced and contain a code block with three lines of code.

### Actual outcome

Whereas the HTML document `example-01.html` contains a code block with three lines of code, the code block in the HTML document `example-02.html` contains an extra blank line after every line of code from the original LaTeX document and totals six lines of code.

To show the difference between the two documents, here is the output of the unix command `diff example-01.html example-02.html`:

```
7,8c7,8
< <link href='example-01.css' rel='stylesheet' type='text/css' />
< <meta content='example-01.tex' name='src' />
---

> <link href='example-02.css' rel='stylesheet' type='text/css' />
> <meta content='example-02.tex' name='src' />

10,12c10,16
< <pre class='fancyvrb' id='fancyvrb1'><a id='x1-3r1'></a><span class='cmtt-10'>foo</span>
< <a id='x1-5r2'></a><span class='cmtt-10'>bar</span>
< <a id='x1-7r3'></a><span class='cmtt-10'>baz</span></pre>
---

> <pre class='fancyvrb' id='fancyvrb1'>
> <a id='x1-3r1'></a><span class='cmtt-10'>foo</span>
>
> <a id='x1-5r2'></a><span class='cmtt-10'>bar</span>
>
> <a id='x1-7r3'></a><span class='cmtt-10'>baz</span>
> </pre>

```

### Discussion

It seems that the issue stems from the lack of support for the `\VerbatimInput` command in TeX4ht. However, the `\VerbatimCommand` is used to input verbatim text in the LaTeX definitions of the Markdown package for TeX and cannot be easily substituted with the `Verbatim` environment. A fix or a workaround would be appreciated.