[Tex/LaTex] the correct way to delineate directories in Lua

best practiceslualuatex

I have been experimenting with some Lua code to list directories and provide them to the TeX engine.

I have been using the Lua File System (lfs) module.

The first part list the current directory (code line 4) and it is printed using \, as C:\Users\Admin\...

In the second part I iterate over the directory which I am providing as a variable, 

`local z="C:/test"`

This also works if I provide it as: `local z="C:\test"

The library accepts this as a valid directory. I am curious to find out how well this will work on other operating systems (I have tested on Windows) and what is the best practice in this regard.

enter image description here

Full MWE listing follows. (Warning it can print 100s of pages if you test on C: alone, create a small temporary directory to test).

\documentclass{tufte-book}
\usepackage[listings]{tcolorbox}
\lstloadlanguages{[LaTeX]TeX, [primitive]TeX}
\usepackage{luacode} % loads luatexbase as well
% Emphasis
%\renewcommand{\ttdefault}{cmtt}            % prefer old tt font
\newcommand\emphasis[2][blue]{\lstset{emph={exec,if,then,else,do,end,while,for,print,sprint,directlua,#2},
   emphstyle={\ttfamily\textcolor{#1}}}}%

\lstset{language={[LaTeX]TeX},
      escapeinside={{(*@}{@*)}}, 
      numbers=left, 
      gobble=0,
      stepnumber=1,numbersep=5pt, 
       numberstyle={\footnotesize\color{gray}},%firstnumber=last,
      breaklines=true,
      framesep=5pt,
      basicstyle=\small\ttfamily,
      showstringspaces=false,
      keywordstyle=\ttfamily\textcolor{blue},
      stringstyle=\color{orange},
      commentstyle=\color{black},
      rulecolor=\color{gray!10},
      breakatwhitespace=true,
     showspaces=false,  % shows spacing symbol
     xleftmargin=0pt,
     xrightmargin=5pt,
     aboveskip=3pt, % compact the code looks ugly in type
     belowskip=7pt,  % user responsible to insert any skips
      backgroundcolor=\color{gray!15}}
\begin{document}

%\begin{tcblisting}{} uncomment if you have the latest version of tcolorbox
\begin{luacode}
  require "lfs"
  local temp=lfs.currentdir()
  tex.sprint(-2, temp)
  tex.sprint("\\par")
  function attrdir (path)
    for file in lfs.dir(path) do
        if file ~= "." and file ~= ".." then
            local f = path..'/'..file
            tex.sprint (-1, f.."\\par     ")
            local attr = lfs.attributes (f)
            assert (type(attr) == "table")
            if attr.mode == "directory" then
                attrdir (f)
            else
               -- for name, value in pairs(attr) do
                    --tex.sprint (-2,name, value)
                -- end
            end
        end
    end
  end
  local z="C:/test"
  attrdir (z)
\end{luacode}
%\end{tcblisting}
\end{document}

Best Answer

You can use / for path separators on both unix and windows. "google" tells me that windows software also accepts / as a separator, but you can't use it on the command line as it denotes an option / command line argument.

Instead of writing tex.sprint(-1, f.."\\par ") you should write tex.tprint({-2 , f},{"\\par "}) and you can use lfs.isdir() to check for a directory. Otherwise a good solution.

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