\subtitle undefined with LaTeX default template

[maccadia]

Hi,

When I override \maketitle using header-include with this code :

---
title:  "De la possibilité et de la réalité de l'introspection"
subtitle: "Une exploration intérieure"
author: "Archibald Dulapin"
header-includes:
  - |
    ```{=latex}
    \makeatletter
    \renewcommand{\maketitle}{%
        \@title

        \@author
        
        \@subtitle
    }
    \makeatother
    ```
...

I get the following error with pandoc 2.2.1:

$ pandoc test.yml -o test.pdf
Error producing PDF.
! Undefined control sequence.
\maketitle ...title \par \@author \par \@subtitle 
                                                  
l.73 \maketitle

It works if I use a modified default.latex template with :

\makeatletter
\providecommand\subtitle[1]{\renewcommand\@subtitle{#1}}
\providecommand\@subtitle{\@latex@error{No \noexpand\subtitle given}\@ehc}
\makeatother
\subtitle{$subtitle$}

I don't know if this code could have any side effect ; I don't understand it well enough. I got it from here.

As for a workaround, putting the \providecommands in header-include works.

[mb21]

Please ask questions this on pandoc-discuss. This tracker is for issues only.

(btw, not sure what you're asking anyway... seems like you got it working somehow)

[maccadia]

Hi, sorry if I wasn't clear.

My point is that the default.latex template could be improved with :

$if(subtitle)$
\makeatletter
\providecommand\subtitle[1]{\renewcommand\@subtitle{#1}}
\providecommand\@subtitle{\@latex@error{No \noexpand\subtitle given}\@ehc}
\makeatother
\subtitle{$subtitle$}
$endif$

instead of

$if(subtitle)$
\providecommand{\subtitle}[1]{}
\subtitle{$subtitle$}
$endif$