sub fullname {
  my (@parts) = @_;
  
  for my $p (@parts) {
    $p = length($p) > 1 ? $p        : # not a single - don't change
         $p =~ /[a-z]/i ? $p . '.'  : # single letter - add a dot
         $p;                          # not a letter - don't change
  }  
  my $name = join(" ", @parts);
  return $name;
}

##</code><code>##

$p =~ /\d/  ? '$' . $p     : # single digit - add a $