#!/usr/bin/perl -w
# chipher PATTERN [< WORDLIST] - search dictionary for words
#
# lowercase letters match literally
# uppercase letters all refer to the same unknown letter
# * matches any sequence of letters

use strict;

if (-t) {
	open(STDIN, "<", "/usr/share/dict/words")  or die "no more words: $!\n";
}

$_ = shift;
my @avoid = do {
	my @lits = /[a-z]/g;
	@lits ? "[" . join("", @lits) . "]" : ()
};
my %template;
my $regex = "^";
for (split //) {
	if (/[a-z]/) {
		$regex .= "$_";
	} elsif (/[A-Z]/) {
		if (exists $template{$_}) {
			$regex .= $template{$_};
		} else {
			my $id = 1 + keys %template;
			if (@avoid) {
				$regex .= "(?!" . join("|", @avoid) . ")";
			}
			$regex .= "(.)";
			push @avoid, $template{$_} = "\\$id";
		}
	} elsif (/\*/) {
		$regex .= ".*";
	} else {
		warn "ignoring $_";
	}
}
$regex .= "\$";
warn "$_ => $regex\n";

my $matches = 0;
while (<>) {
	if (/$regex/i) {
		print;
		$matches++;
	}
}

exit !$matches;