Backslash in block quotes causes errors

[Witiko]

Discussed in #494

^{Originally posted by l0th3r September 6, 2024}
Hi,
I am new to Tex and LaTex.

@Witiko let me know if this should be in issues instead of here.
When using backslash for new line in a block quote, it causes long series of errors.

Test tex file:

\documentclass{article}
\usepackage{markdown}

\begin{document}
\begin{markdown}
> **TITLE** \
> Lorem ipsum dolor sit amet
\end{markdown}
\end{document}

Thank you in advance for your time and help.

[Witiko]

@Witiko let me know if this should be in issues instead of here.

It should, I just transferred it.

When using backslash for new line in a block quote, it causes long series of errors.

Converting he above code with the Markdown package 3.7.0 produces the following TeX code:

\markdownRendererDocumentBegin
\markdownRendererBlockQuoteBegin
\markdownRendererStrongEmphasis{TITLE}\markdownRendererError{parse_inlines_no_link_or_emphasis failed on:
 \markdownRendererBackslash{}
> Lorem ipsum dol}\markdownRendererBlockQuoteEnd

There are two issues here:

1. We fail to parse a completely valid Markdown input. I added a regression test in commit 86efd5c from draft PR #496.

2. \markdownRendererError chokes on the error text, since it incorrectly calls \markdownError. Here is the necessary change of file kpsewhich markdownthemewitiko_markdown_defaults.tex:

   170c170
   < \let\markdownRendererErrorPrototype\markdownError
   ---
   > \def\markdownRendererErrorPrototype#1{\markdownError{#1}{}}

   After this change, compiling the above code produces this more informative error message:

   ! Package markdown Error: parse_inlines_no_link_or_emphasis failed on:
   (markdown)                \TU\textbackslash {} > Lorem
   (markdown)                ipsum dol
   

   There are other changes that should be done. For example, the parameter of \markdownRendererError should be only minimally escaped, allowing a more readable error message:

   ! Package markdown Error: parse_inlines_no_link_or_emphasis failed on: \ >
   (markdown)                Lorem ipsum dol
   

   Alternatively and perhaps more appropriately, the default renderer prototype should redefine the special symbol renderers and expand the message text before logging it.

[Witiko]

There are two issues here:

1. We fail to parse a completely valid Markdown input. I added a regression test in commit 86efd5c from draft PR #496.

@l0th3r: This has been fixed in commit 322f91f from PR #495. I should have #495 merged next Monday. However you should be able to patch your copy of file markdown-parser.lua right now based just on 322f91f. Early feedback welcome.