[Tex/LaTex] Making hhline work together with arydshln

Question

I am trying to create Optimality Theory tableaux (a specific type of tables used in linguistics). These tableaux generally look like the following – the important thing is that both the first column and the first row are "separated" from the rest of the table:

(note that in larger tables, the 2nd to nth columns and rows look like in any other table; that is, they are separated by a single line only)

MWE that works:

\documentclass{scrartcl}
%\usepackage{arydshln}
\usepackage{hhline}
%\usepackage{arydshln}
\begin{document}
\begin{tabular}{|r||c|}\hhline{|-||-|}
a & b\\\hhline{:=::=:}
c & d\\\hhline{|-||-|}
\end{tabular}
\end{document}

The problem is that I also require the ability to use a dashed vertical line in my tables instead of the regular |. The arydshln package provides this; it allows you to use : in your tabular spec to get a dashed line.

The problem is that even loading this package (before or after hhline) screws up the table — the below is just with either of the commented lines in the MWE uncommented:

I have been able to find three references that have a samilar problem, in that their posters were attempting to use arydshln and hhline together:

• Dashed hline in longtabu (arydshln conflicts, does not work?)

• Conflict between \hline and arydshln in aligned environment?

• Tables with colored cells and dashed lines

But these problems were all solved by using a different approach, e.g. using TikZ to draw the "table". This is not an option for me; I really wish to use the tabular environment here. Is it in any way possible to have both dashed vertical lines (what I need arydshln for) and to be able to "separate" the first column and the first row from the rest of the table as in the first picture?

Answer 1

tabu seems very powerful but I guess you would only need something fairly simple in this case:

\documentclass{article}
\usepackage{hhline,tabu}
\begin{document}
  \newtabulinestyle { mystyle=.5pt on 1.5pt  off 1.5pt }
  \begin{tabu}{| r || *{3}{c|} c |[mystyle] c |}\hhline{|-||*{5}{-|}}
    a & b & e & f & i & j\\\hhline{:=::*{5}{=:}}
    c & d & g & h & k & l\\\hhline{|-||*{5}{-|}}
    m & n & o & p & q & r\\\hhline{|-||*{5}{-|}}
  \end{tabu}
\end{document}