feat: capcont-text

[sam-maloney]

This adds a new template capcont-text (and capcont-pre) so that capcont is no longer hard-coded to use conthead-* templates. This is useful when one wants to format long tables with captions in the footer rather than the header, where otherwise one currently has to either redefine capcont to use contfoot-text or swap the meaning of conthead-text and contfoot-text, which is confusing.

I haven't documented anything in the manual yet, but am happy to do so if others agree with the idea itself; I'm also very open to other suggestions to achieve the desired outcome in a clean manner!

Essentially I would like to be able to do this:

% simply change `capcont-text` to use footer text instead of header text
\DeclareTblrTemplate{capcont-text}{default}{\UseTblrTemplate{contfoot-text}{default}}
\DeclareTblrTemplate{firsthead}{default}{}
% headers then use standard `conthead` template
\DeclareTblrTemplate{middlehead,lasthead}{default}{\UseTblrTemplate{conthead}{default}}
% and `capcont` is used the footer
\DeclareTblrTemplate{firstfoot,middlefoot}{default}{\UseTblrTemplate{capcont}{default}}
\DeclareTblrTemplate{lastfoot}{default}{
  \UseTblrTemplate{caption}{default}
  \UseTblrTemplate{note}{default}
  \UseTblrTemplate{remark}{default}
}

instead of either this:

% swap the header and footer text
\DeclareTblrTemplate{conthead-text}{default}{\tblrcontfootname}
\DeclareTblrTemplate{contfoot-text}{default}{\tblrcontheadname}
\DeclareTblrTemplate{firsthead}{default}{}
% and now the headers use the `contfoot` template, which is semantically confusing
\DeclareTblrTemplate{middlehead,lasthead}{default}{\UseTblrTemplate{contfoot}{default}}
% the rest is the same
\DeclareTblrTemplate{firstfoot,middlefoot}{default}{\UseTblrTemplate{capcont}{default}}
\DeclareTblrTemplate{lastfoot}{default}{
  \UseTblrTemplate{caption}{default}
  \UseTblrTemplate{note}{default}
  \UseTblrTemplate{remark}{default}
}

or having to redefine the entire capcont template, which is annoying for such a simple switch if one wants to preserve the full normal template behaviour:

LaTeX code

\ExplSyntaxOn
% have to copy-and-paste the whole definition from `tabularray.sty`
\DeclareTblrTemplate { capcont } { normal }
  {
    \hbox_set:Nn \l__tblr_caption_box
      {
        \UseTblrTemplate { caption-tag } { default }
        \UseTblrTemplate { caption-sep } { default }
        \UseTblrTemplate { caption-text } { default }
        \UseTblrTemplate { conthead-pre } { default }
        \UseTblrTemplate { contfoot-text } { default } % just to change `conthead-text` to `contfoot-text`
      }
    \dim_compare:nNnTF { \box_wd:N \l__tblr_caption_box } > { \hsize }
      {
        \UseTblrAlign { capcont }
        \UseTblrIndent { capcont }
        \hbox_set:Nn \l__tblr_caption_left_box
          {
            \UseTblrTemplate { caption-tag } { default }
            \UseTblrTemplate { caption-sep } { default }
          }
        \hangindent = \box_wd:N \l__tblr_caption_left_box
        \hangafter = 1
        \UseTblrHang { capcont }
        \leavevmode
        \hbox_unpack:N \l__tblr_caption_box
        \par
      }
      {
        \centering
        \makebox [\hsize] [c] { \box_use:N \l__tblr_caption_box }
        \par
      }
  }
\ExplSyntaxOff
% and the rest is the same as the first example, where the above was simplified to one line
\DeclareTblrTemplate{firsthead}{default}{}
\DeclareTblrTemplate{middlehead,lasthead}{default}{\UseTblrTemplate{conthead}{default}}
\DeclareTblrTemplate{firstfoot,middlefoot}{default}{\UseTblrTemplate{capcont}{default}}
\DeclareTblrTemplate{lastfoot}{default}{
  \UseTblrTemplate{caption}{default}
  \UseTblrTemplate{note}{default}
  \UseTblrTemplate{remark}{default}
}