dtxmk.latexmkrc

#---
# Populate the @default_files list with the files 
# generated by the docstrip \generate command

# check if one file is newer than another
sub nt {
    return (stat($_[0]))[9] > (stat($_[1]))[9];
}

# slurp a file into a string
sub read_file {
    my($file) = @_;
    open my $fh, '<', $file or die "Can't open file $!";
    read $fh, my $text, -s $fh;
    return $text;
}

# the files generated by running docstrip on the given files
sub dtx_generated_files {
    my @all_files = ();
    foreach (@_) {
        my $dtx_file = $_;
        (my $dtx_log = $dtx_file) =~ s/.dtx$/.log/;
        system ("tex $dtx_file") if (! (-e $dtx_log) || nt($dtx_file,$dtx_log));
        # slurp log file into string.  
        # See https://www.perl.com/article/21/2013/4/21/Read-an-entire-file-into-a-string/
        my $dtx_log_text = read_file($dtx_log);
        $dtx_log_text =~ s/\n//g;
        (my $gen_files_str) = $dtx_log_text =~ /Generating file\(s\) (.*?)\\openout/;
        push @all_files, split(/\s/, $gen_files_str);
    }
    return @all_files;
}

# add the .tex files generated by any .dtx file to the argument list
# and mark the dtx files which generate .tex files for deletion from the arg list
my %dtx_togo;
foreach (@ARGV) {
    next unless /\.dtx$/;
    if (my @generated_tex_files = grep { /\.tex$/ } dtx_generated_files($_)) {
        push @ARGV, @generated_tex_files;
        $dtx_togo{$_} = 1;
    }
    
}
# delete those marked .dtx files from the argument list.
@ARGV = grep { !$dtx_togo{$_} } @ARGV;