/**
  * Create an array of values to use in place of variables in template strings
  *
  * @param BfoxRef $ref
  * @return array
  */
 private static function template_vars(BfoxRef $ref)
 {
     $book_name = '';
     $ch1 = $vs1 = 0;
     if ($ref->is_valid()) {
         $bcvs = BfoxRef::get_bcvs($ref->get_seqs());
         $books = array_keys($bcvs);
         $book_name = BibleMeta::get_book_name($books[0]);
         $cvs = array_shift($bcvs);
         $cv = array_shift($cvs);
         list($ch1, $vs1) = $cv->start;
     }
     return array('%ref%' => urlencode($ref->get_string()), '%book%' => urlencode($book_name), '%chapter%' => $ch1, '%verse%' => $vs1);
 }
 /**
  * Subtract bible references
  *
  * @param BfoxRef $ref
  */
 public function sub_ref(BfoxRef $ref)
 {
     return $this->sub_seqs($ref->get_seqs());
 }