Tabular edge-to-edge dotted line: suppress overshoot, reduce dotsize, align dots to edges

Question

I am trying to add dotted line from left-edge to right-edge of tabular after rows. There are 3-problems with my best attempt (code & screenshot below): 1) The length of the dotted line equals width of minipage instead of table, 2) The dots don't exactly start at left edge of the table (there is a slight gap), 3) Reducing dot size also changes the start point of the dotted line, further mismatching the start points of lines with different dot sizes (I would like to have lines with different dot sizes, but all starting & ending at same edge). The left edge of the leftmost dot should touch the left edge of table (just like \hrule used on the first line), and right edge of the rightmost dot should touch the right edge of the table. I am using lualatex.

NOTE: I have come across hacks on stack exchange that use dashes instead of dots, I am looking for dots so please don't post any dash answers. Also, I cannot move to another environment for now, so it has to be a solution for tabular environment. Also, please don't post tikz or other slow drawing tricks. If it isn't clear from the description: I don't intend to manually specify length of the table length like n pt/cm/in, the solution would be able to figure out length of table just like the \hrule I use for the first line. Lastly: Given the emphasis on PDF tagging & accessibility in TUG 2020, the solution ideally won't make pdf-accessibility text-to-speech utility to start speaking 'dot dot dot dot dot...' a gazillion times.

Code:

% >> lualatex table.tex
\documentclass[notitlepage,letterpaper]{article}
\usepackage{array}
\begin{document}

\begin{minipage}[t][1in][t]{3in}
    Hello world!\\
    \begin{tabular}[t]{@{}rll@{}}
            \noalign{\hrule height 0.5pt}
        a & some & text \\
            \noalign{\dotfill}
        b & some & other text \\
            \noalign{\dotfill}
        b & some more & text \\
            \noalign{\dotfill}
    \end{tabular}%
\end{minipage}

\end{document}

Screenshot: (I intend to start smaller sized dotted line from left edge of red box, and end it at its right edge (ideally the dots touching the edge))

Answer 1

Adapted from my answer at Dotted line instead of \hline in table environment, to include \xleaders rather than \leaders, for improved flushness, and to provide an optional inclusion of dots for each column's margin, allowing it to be used with @{} column-margin specifications. Also, it now works for more than a 2-column tabular.

In an effort to better match left and right margins, two additional EDITS were made to the adaptation:

1. specified sidebearings to the dot were accounted for.

2. A final right-column kern was required to subtract off one \replength of leader minus the width of the (sidebearing-free) dot

The values of \replength and \dotscale can be changed on a column by column basis, if desired. Unfortunately, I can not construct the dots as a single leader, but must handle it column by column. Since I use \xleader to achieve flushness, this means that the dot separation in each column will be slightly different, based on the column width and the values of \replength and \tabcolsep.

\documentclass{article}
\usepackage{graphicx}
\newlength\replength
\setlength\replength{1.3pt}% HORIZONTAL DOT SEP
\newcommand\dotscale{.5}% SCALES DOT SIZE
\newcommand\sidebearing{.9pt}% DOT'S SIDEBEARING
\newsavebox\mydot
\newcommand\tdotfill[1][\repfrac]{\xleaders\hbox to \replength{%
  \smash{\raisebox{\arraystretch\dimexpr\ht\strutbox-.1ex\relax}%
    {\usebox{\mydot}}}}%
  \hfill}
\newcommand\tdotleft[1][\tabcolsep]{%
  \makebox[0pt][r]{\makebox[#1]{\tdotfill}}}
\newcommand\tdotright[1][\tabcolsep]{%
  \makebox[0pt][l]{\makebox[#1]{\tdotfill}}}
\newcommand\tabdotline[1][Q]{%
  \savebox\mydot{%
    \scalebox{\dotscale}{\kern-\sidebearing.\kern-\sidebearing}}%
  \ifx l#1\relax\tdotleft\tdotfill\else
  \ifx r#1\relax\tdotfill\tdotright\else
  \ifx \relax#1\relax\tdotfill\else
  \tdotleft\tdotfill\tdotright 
  \fi\fi\fi\mbox{}}
\newcommand\dotend{\unskip\kern\dimexpr\wd\mydot-\replength\relax
  \\[-\arraystretch\dimexpr\ht\strutbox+\dp\strutbox\relax]}
\begin{document}
\begin{minipage}[t][1in][t]{3in}
    Hello world!\\
    \begin{tabular}[t]{@{}rll@{}}
            \noalign{\hrule height 0.5pt}
        a & some & text \\
          \tabdotline[r] &  \tabdotline &\tabdotline[l] \dotend
        b & some & other text \\
          \tabdotline[r] &  \tabdotline &\tabdotline[l] \dotend
        b & some more & text \\
          \tabdotline[r] &  \tabdotline &\tabdotline[l] \dotend
    \end{tabular}%
\end{minipage}
\end{document}

Answer 2

Here is what you can do with {NiceTabular} of nicematrix. That environment is similar to {tabular} (of array) but adds PGF/Tikz nodes under the rows, cells and columns of the array.

It's possible to use that nodes to draw dotted rules with Tikz.

\documentclass[notitlepage,letterpaper]{article}
\usepackage{nicematrix}
\usepackage{tikz}

\begin{document}


\ExplSyntaxOn
\makeatletter
\NewDocumentCommand { \mydottedline } { }
  {
    \tl_gput_right:Nx \g_nicematrix_code_after_tl
      {
        \exp_not:N \tikz [dotted]
          \exp_not:N \draw (\int_use:N \c@iRow -| 1 ) 
                -- (\int_use:N \c@iRow -|\exp_not:N \int_eval:n { \c@jCol + 1 } ) ;
      }
  }
\makeatother
\ExplSyntaxOff  
  
\begin{minipage}[t][1in][t]{3in}
    Hello world!\\
    \begin{NiceTabular}[t]{@{}rll@{}}
        \noalign{\hrule height 0.5pt}
        a & some & text \\
            \mydottedline
        b & some & other text \\
            \mydottedline
        b & some more & text \\
            \mydottedline
    \end{NiceTabular}%
\end{minipage}

\end{document}

Answer 3

https://tex.stackexchange.com/a/332124/197451

This should point you in the right direction

\documentclass{article}

\newcommand\fillin[1][3cm]{\makebox[#1]{\dotfill}}
\begin{document} 
Why appropriate, specify? \fillin\\ 


Why inappropriate, specify? \fillin[4cm]\\ 


Why appropriate, specify? \dotfill\\


Why inappropriate, specify? \fillin[2cm]
\end{document}