#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;
use autodie;

# Possibly read from command line, database, file, etc.
my @in_patterns = qw{..AA.BB... AB.BA.......};

# Prefer exclusion (blacklist) over inclusion (whitelist).
# Here, exclude proper nouns
#   and any words with non-alphabetic characters.
# Note: in other scenarios, whitelists are better;
#   e.g. only allow access to X, Y & Z.
my $blacklist_re = qr{(?:^[A-Z]|[^A-Za-z])};

# Point to your preferred dictionary. Some on my system:
#my $dict = '/usr/share/dict/words'; # --> linux.words
my $dict = '/usr/share/dict/strine'; # --> australian-english

open my $dict_fh, '<', $dict;

for my $in_pat (@in_patterns) {
    say "*** Input Pattern: $in_pat";

    my $len = length $in_pat;
    my $match_re = '';
    my %seen;
    my $count = 0;

    for my $char (split //, $in_pat) {
        if ($char eq '.') {
            $match_re .= '.';
        }
        elsif (! $seen{$char}) {
            $match_re .= '(.)';
            $seen{$char} = ++$count;
        }
        else {
            $match_re .= "\\$seen{$char}";
        }
    }

    say "*** Match Pattern: $match_re";
    my $qr_re = qr{^$match_re$};
    say "*** QR Regex: $qr_re";

    seek $dict_fh, 0, 0;

    while (<$dict_fh>) {
        chomp;
        next unless length($_) eq $len;
        next if $_ =~ $blacklist_re;
        next unless $_ =~ $qr_re;
        say;
    }
}

##</code><code>##

*** Input Pattern: ..AA.BB...
*** Match Pattern: ..(.)\1.(.)\2...
*** QR Regex: (?^:^..(.)\1.(.)\2...$)
barrelling
barrenness
...
tunnellers
tunnelling
*** Input Pattern: AB.BA.......
*** Match Pattern: (.)(.).\2\1.......
*** QR Regex: (?^:^(.)(.).\2\1.......$)
minimisation
monomaniacal
...
reverberates
secessionist