Alphabet:    abcdef
Translation: d a  c

##</code><code>##

my $alpha = "abcdef";
my $cipher = "abcadbbe";
my $word   = "deadbeef";

extend_translation( $alpha, "      ", $cipher, $word );
# should return "deabf "
# note that when the entire translation is given as 
# only ' 's, this sub should always return a new 
# translation string

extend_translation( $alpha, "     c", $cipher, $word );
# should return "deabfc"

extend_translation( $alpha, "c     ", $cipher, $word );
# should return 0 or undef, since cipher 'a' is already
# representing normal 'c', and the two words would 
# require that 'a' means 'd', instead, so the 
# translation cannot work in this case.

my $tr = extend_translation( $alpha, "     ", "ebba", "feed" );
# after this step, $tr = "de  f "
if ( $tr ) { 
    $tr = extend_translation( $alpha, $tr, $cipher, $word );
    # after this step, $tr = "deabf "
}

##</code><code>##

my $alpha = "elprxyz";
my $cipher = "zyxe";
my $normal = "perl";

my @array = translation_set( $alpha, $cipher, $normal );

foreach my $trans ( @array ) {
   $_ = $cipher;
   eval "tr/$alpha/$trans/";  #need to eval in order to 
                              #expand variables
   print $trans, ": ", $_,"\n";
}

# Would expect (but not necessarily in this order:)
# lxyzrep: perl
# lxzyrep: perl
# lyxzrep: perl
# lyzxrep: perl
# lzxyrep: perl
# lzyzrep: perl