Compiling document with PerlTeX, then luaLaTeX - conditional \usepackage based on compilation tool

Question

Slightly connected to my previous question (Output of PerlTex with current TeXlive on Windows), I have managed to generate .pdf files with PerlTeX (precisely, with option --latex=lualatex).

Next step to use this wonderful tool fully would be to be able to use it along with other tools I am already using and automate document creation.

As stated in PerlTeX documentation, page 8, I am compiling document with options:

--latex=lualatex --makesty

With that, file noperltex.sty is created. Then, after commenting out \usepackage{perltex} and adding \usepackage{noperltex}, the document can be compiled with only lualatex, not requiring perltex to compile. If I would need to compile document twice, but first with perltex, then with only lualatex, is there a way, how to do that conditionally?

If I may, it would be great to have solution involving arara, making the compilation also automatic.

I have already created a rule for arara to work with perltex (my first attempt, based on biber rule and rule for pythontex, so its very basic), in case of arara solution please consider next code:

perltex.yaml

!config
# perltex rule for arara
# author: Tomas Krulis based on Uwe Ziegenhagen
# requires arara 4.0+
identifier: perltex
name: perltex
commands:
- name: PerlTeX for advanced string manipulation
  command: >
    @{
        return getCommand('perltex', options, getBasename(file));
    }
arguments:
- identifier: options
  flag: >
    @{
        if (isList(parameters.options)) {
            return parameters.options;
        }
        else {
            throwError('I was expecting a list of options.');
        }
    }

For testing, please consider next MWE:

% arara: perltex: { options: [ '--latex=lualatex', '--makesty' ] }
% arara: lualatex

\documentclass[11pt]{article}
\usepackage{fontspec}
\usepackage{xcolor}

\usepackage[optional]{perltex}
%\usepackage{noperltex}

\ifperl

\perlnewcommand{\reversewords}[1]{join " ", reverse split " ", $_[0]}

\perlnewcommand{\hilbertmatrix}[1]{
my $result = '
\[
\renewcommand{\arraystretch}{1.3}
';
$result .= '\begin{array}{' . 'c' x $_[0] . "}\n";
foreach $j (0 .. $_[0]-1) {
my @row;
foreach $i (0 .. $_[0]-1) {
push @row, ($i+$j) ? (sprintf '\frac{1}{%d}', $i+$j+1) : '1';
}
$result .= join (' & ', @row) . " \\\\\n";
}
$result .= '\end{array}
\]';
return $result;
}

\else

\newcommand{\reversewords}[1]{\color{red} #1}
\newcommand{\hilbertmatrix}[1]{\color{red} #1}

\fi

\begin{document}

\reversewords{Try doing this without Perl!}

\clearpage

\hilbertmatrix{20}

\end{document}

Please note, that document "works" as it is, but only thanks to conditional \ifperl, which simply sets any perlcommand argument to red text. The desired behavior is to compile with perltex and \usepackage{perltex}, then conditionally switch to \usepackage{noperltex}, when the document is compiled only with lualatex; so the \else part of \ifperl is not trigerred.

Thank very much for any insight in this, maybe peculiar, question.

EDIT: Updated MWE based on suggestion of Mrs. Fischer, to test with condition \IfFileExists. With arara, in step 2, of "only" luaLaTeX compilation, I am still getting "undefined control sequence" error with \perlnewcommand ; which leads me to think that still the \usepackage{noperltex} is not being picked up.

More interestingly, if I compile following MWE with PerlTeX only, I get the same error. I also have already noperltex.sty in project folder, with code, that (I think) doesnt involve definitions of \perlnewcommands in form, that could be processed by lualatex.

Looks like noperltex is created at start of perltex compilation, which prevents else part of \IfFileExists triggering. Is that the bug you encountered? Or is it intended?

EDITED MWE:

% arara: perltex: { options: [ '--latex=lualatex', '--makesty', '--nosafe' ] }
% arara: lualatex: { shell: yes }

\documentclass[11pt]{article}
\usepackage{fontspec}
\usepackage{xcolor}

\IfFileExists{noperltex.sty}{%
\usepackage{noperltex}%
}%
{\usepackage[optional]{perltex}}

\perlnewcommand{\reversewords}[1]{join " ", reverse split " ", $_[0]}

\perlnewcommand{\hilbertmatrix}[1]{
my $result = '
\[
\renewcommand{\arraystretch}{1.3}
';
$result .= '\begin{array}{' . 'c' x $_[0] . "}\n";
foreach $j (0 .. $_[0]-1) {
my @row;
foreach $i (0 .. $_[0]-1) {
push @row, ($i+$j) ? (sprintf '\frac{1}{%d}', $i+$j+1) : '1';
}
$result .= join (' & ', @row) . " \\\\\n";
}
$result .= '\end{array}
\]';
return $result;
}

\begin{document}

\reversewords{Try doing this without Perl!}

\clearpage

\hilbertmatrix{20}

\end{document}

Answer 1

Since you are using arara (thank you!), how about the following approach:

1. Let's create a new rule named writeconfig.yaml which, as the name indicates, creates a configuration file based on the provided text:

   !config
   identifier: writeconfig
   name: WriteConfig
   authors:
   - Paulo Cereda
   commands:
   - name: Writing the configuration file
     command: >
       @{
           writeToFile(toFile(input), text + '\n', append);
           return true;
       }
   arguments:
   - identifier: input
     flag: >
       @{
           return parameters.input;
       }
     required: true
   - identifier: append
     flag: >
       @{
           return isTrue(parameters.append);
       }
     default: false
   - identifier: text
     flag: >
       @{
           return parameters.text;
       }
     required: true
   

   This rule takes at least two parameters, namely:

   • input (required): the name of our configuration file.
   • text (required): the text to be written.
   • append (optional): a flag indicating whether the content should be appended or overwritten (default behaviour is to overwrite the content, as we want to exploit this dea).

   Prior to revision 2, arara 4.0 had a bug when handling boolean values as a return type for commands (as seen in issue #128). Make sure to update arara to at least revision 2 using your TeX distro manager, so the aforementioned rule will have the expected behaviour. You can check the revision by looking at the header when running the tool: arara 4.0 (revision 2)

2. Change your document and replace these lines:

   \usepackage[optional]{perltex} % for PerlTeX
   \usepackage{noperltex}         % for LuaLaTeX
   

   by this one:

   \input{config.cfg}
   

3. Now let's create new directives:

   % arara: writeconfig: { input: 'config.cfg', text: '\usepackage[optional]{perltex}' }
   % arara: perltex: { options: [ '--latex=lualatex', '--makesty' ] }
   % arara: writeconfig: { input: 'config.cfg', text: '\usepackage{noperltex}' }
   % arara: lualatex
   

4. Have fun:

 $ arara mwe.tex 
   __ _ _ __ __ _ _ __ __ _ 
  / _` | '__/ _` | '__/ _` |
 | (_| | | | (_| | | | (_| |
  \__,_|_|  \__,_|_|  \__,_|

 Processing 'mwe.tex' (size: 1003 bytes, last modified: 09/10/2019
 11:03:14), please wait.

 (WriteConfig) Writing the configuration file ............ SUCCESS
 (perltex) PerlTeX for advanced string manipulation ...... SUCCESS
 (WriteConfig) Writing the configuration file ............ SUCCESS
 (LuaLaTeX) LuaLaTeX engine .............................. SUCCESS

 Total: 2.60 seconds

Hope it helps! :)

EDIT: My suggestion is to keep both writeconfig.yaml and perltex.yaml inside your project directory. Then create a file named arararc.yaml (it's one of the four possible names for this file, I usually prefer this one) and add this to it:

!config
paths:
- '.'

It means to search the current project directory for rules first. Then try to run arara from this level.