Latex/PDF: change longtable to be correctly row colored

[salim-b]

If one would like to have zebra striped table rows (or any other kind of row coloring) in the PDF output converted from Pandoc Markdown, the longtable environment could be redefined in the YAML header like the following:

---
header-includes:
  - \usepackage[table]{xcolor}
  - \definecolor{lightgray}{gray}{0.95}
  - \let\OldLongtable\longtable
  - \let\OldEndLongtable\endlongtable
  - \renewenvironment{longtable}{\rowcolors{1}{white}{lightgray}\OldLongtable}{\OldEndLongtable}
---

Now the problem with this is that the resulting row coloring is wider than the actual table. Therefore I've asked for a solution on the Tex/Latex Stack Exchange site and a user called Zarko recently provided a workaround – but on the level of the intermediary Latex code. Right now the longtable for a 4-column table with right-left-left-center alignments produced by Pandoc starts with

\begin{longtable}[]{@{}rllc@{}}

Zarko changed this into

\begin{longtable}[]{@{} >{\columncolor{white}[0pt][\tabcolsep]}rll >{\columncolor{white}[\tabcolsep][0pt]} c@{}}

which makes the row coloring the correct width.

Now I wonder if his adjustmens could be somehow incorporated into Pandoc or it's default Latex template to allow users to define zebra-striped tables. 🙂

(Unfortunately I'm not proficient enough to assess – not to speak of implement – this.)

Addendum:
As Zarko pointed out, just removing the two @{} so that the longtable begins only with

\begin{longtable}[]{rllc}

also fixes the problem. But I guess the @{} do serve some purpose, right?

[mb21]

there's also quite some discussion about table LaTeX output in this issue: #1023

[Wandmalfarbe]

This seems to be a duplicate of #3929.

[mb21]

Duplicate of #3929