Error creating PDF from markdown with Lua fenced code block

[NDietrich]

There is an issue when generating latex documents from markdown using the listings package for the Lua Language. If you create a PDF directly from markdown there is an issue, but if break the process into two steps (markdown to tex, then tex to pdf there is no issue).

Example markdown code (example.md):

```{.bash firstnumber=100}
echo "this displays corectly with syntax highlighting"
```

```{.Lua firstnumber=100}
print("Also works with Syntax Highlighting")
local function dumphyphens (head)
```

Pandoc is run as follows:

pandoc example.md -o example.tex --listings

the output (example.tex) is as follows:

\begin{lstlisting}[language=bash, firstnumber=100]
echo "this displays corectly with syntax highlighting"
\end{lstlisting}

\begin{lstlisting}[language=Lua, firstnumber=100]
print("Also works with Syntax Highlighting")
local function dumphyphens (head)
\end{lstlisting}

now try creating a PDF from the latex:

pandoc example.tex -o example.pdf

and this generates a PDF with correct color syntax highlighting for the bash code, AND the lua code. Everything is good.

now try again but go straight to PDF from MD:

pandoc example.md -o example.pdf --listings

and you get the following error:

user@computer:~/ $ pandoc example.md -o example.pdf --listings
Error producing PDF.
! Package Listings Error: Couldn't load requested language.

See the Listings package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.65 ...lstlisting}[language=Lua, firstnumber=100]

The tex output by the command is the exact same as in the first case:

\begin{lstlisting}[language=bash, firstnumber=100]
echo "this displays corectly with syntax highlighting"
\end{lstlisting}

\begin{lstlisting}[language=Lua, firstnumber=100]
print("Also works with Syntax Highlighting")
local function dumphyphens (head)
\end{lstlisting}

Running Version 2.5:

user@computer:~/ $ pandoc -v
pandoc 2.5
Compiled with pandoc-types 1.17.5.4, texmath 0.11.1.2, skylighting 0.7.4

[mb21]

So you're saying it works without --listings and doesn't with the option? btw. shouldn't it be a lowercase l in .lua, like:

```{.lua firstnumber=100}

[NDietrich]

You have to use the uppercase Lua in the code fence or it doesn't work (getting lua to work correctly was difficult, and this is what i found worked).

when going straight from markdown to pdf with the following command:

pandoc example.md -o example.pdf --listings

The error i mentioned above is generated.

when going from markdown to tex, and then from tex to pdf the error is not generated, and the pdf is correct (has all the correct syntax highligting for lua and bash):

pandoc example.tex -o example.tex --listings
pandoc example.tex -o example.pdf

However, if you go from .tex to pdf, AND if you add the listings flag at this step, you get the error again:

pandoc example.tex -o example.pdf --listings

[jgm]

We may need to revisit our correspondence to listings language names in T.P.Highlighting.

[jgm]

OK, I think the issue here is that Lua has several variants in listings (5.0, 5.1, 5.2).
In cases like this apparently it's necessary to specify the variant or listings gets confused:
https://tex.stackexchange.com/questions/212069/listings-cannot-load-requested-language

Workaround: add this to your header-includes:

\lstset{defaultdialect=[5.2]Lua}

Not sure what change to pandoc would be best, if any. We could add some default dialects to the default template, but these might not be the dialects the user wants...

[jgm]

Here are the listings languages that have multiple dialect but no preset default dialect:

Assembler (Motorola68k, x86masm)
Lua (5.0, 5.1, 5.2, 5.3)

So I think we could just add this to the default template under $if(listings)$:

\lstset{defaultdialect=[5.3]Lua}
\lstset{defaultdilaect=[x86masm]Assembler}