package Slang;
use Modern::Perl;
use String::CRC32;
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(mask);

our $compiled_masks;

my $debug = 0;

sub mask
   {
    my $crc32 = crc32($_[0]);
    return $compiled_masks->{$crc32} if (defined $compiled_masks->{$crc32});

    my $stash = $_[1];
    my $mask = $_[0];

    say "compiling from scratch" if $debug;

       while ($mask =~ m/<s>([^<]*?)<\/>/gs)
            {
             my $key = $1;

             if ($key =~ m@\.@s)
               {
                say "dot operator detected" if $debug;

                my $value;

                my @keys = split /\./,$key;
                my $first = 1;

                foreach my $new_key (@keys)
                   {
                    say $new_key if $debug;
                    if ($first) { $value = $stash->{$new_key}; $first = 0; }
                    else { $value = $value->{$new_key}; }
                   }

                $mask =~ s/<s>$key<\/>/$value/gs;
               }
             else
               {
                say "edit : $key = $stash->{$key}"  if $debug;
                $mask =~ s/<s>$key<\/>/$stash->{$key}/gs;
               }
            }

      $compiled_masks->{$crc32} = $mask;
      return $mask;

   }