#!/usr/bin/perl -w
#Numbers to letters v2

use strict;
my $count = 0;

my $wlist = "/usr/dict/words";
open (WLIST, "<$wlist") || die "Unable to open $wlist: $!";
my @words = <WLIST>;
my %nums =(   #numbers to letters
	1 => ["L"],
	2 => ["A","B","C"],
	3 => ["D","E","F"],
	4 => ["G","H","I"],
	5 => ["J","K","L"],
	6 => ["M","N","O"],
	7 => ["P","Q","R","S"],
	8 => ["T","U","V"],
	9 => ["W","X","Y","Z"],
	0 => ["O"],
);

print "Please enter the numbers - between 2 and 9\n";
print "Note that 1's will convert to L's and 0's to O's\n: ";
chomp (my $key=<STDIN>);
my @keys=split "",$key;
my $length = scalar @keys;

#call the sub, let it know which letter in the word we are looking at,
#which letters we are looking for and the wordlist -
#this keeps going until there are no more numbers to check 

#this is seperate to give it the "first" list (faster this way)
my $words = &get_wrds($count,$nums{shift @keys},\@words,$length);
++$count;
foreach (@keys){
	$words=&get_wrds($count,$nums{$_},$words);
	++$count;
}
foreach (@{$words}){ 
	#there should only be a couple of N letter words left..
	print "Found $_\n"; 
}

sub get_wrds{
	my $pos   = shift; #position in the word
	my $list  = shift; #list of letters
	my $wlist = shift; #list of words
	my $lng   = shift; #length
	my @words;         #temp storage
	foreach my $let(@{$list}){ 
		foreach (@{$wlist}){
			chomp;
			if ($lng){  #get rid of irrelevant words
				next unless length $_ == $lng;
			}
			if ( index(uc $_,$let,$pos) == $pos){ 
				push @words,$_;      	   
			}
		}
	}
	return \@words; #return matches
}