#!/usr/local/bin/perl
use strict;
use warnings;

my $sandboxxml = do {
    open(my $fh, '<', $ARGV[0]) || die("sandbox xml file cannot be loaded;check for file name or existance");
    local $/; # Slurp
    <$fh>;
};

##</code><code>##

my @tokens;

while ($sandboxxml =~ /<!\[(CDATA)\[|<!--/) {
    if ($1) { # We're in a CDATA block
        $sandboxxml =~ s/<!\[CDATA\[(.*?)\]\]>/'<<' . (0+@tokens) . '>>'/es;
        push @tokens, $1;
    } else { # Comment
        $sandboxxml =~ s/<!--.*?-->//s;
    }
}

##</code><code>##

while ($sandboxxml =~ s#(<[^<>]*(?:/|>(?:[^<>]|<<\d*>>)*</[^<>]*)>)#'<<' . (0+@tokens) . '>>'#es) {
    push @tokens, $1;
}