/*
 * call-seq:
 *   prefix
 *
 * Get the shorthand reference to the namespace associated with the node.
 */
static VALUE prefix(VALUE self)
{
  xmlTextReaderPtr reader;
  Data_Get_Struct(self, xmlTextReader, reader);
  const char * prefix = (const char *)xmlTextReaderConstPrefix(reader);
  if(prefix == NULL) return Qnil;

  VALUE MAYBE_UNUSED(enc) = rb_iv_get(self, "@encoding");
  return NOKOGIRI_STR_NEW2(prefix,
      RTEST(enc) ? StringValuePtr(enc) : NULL);
}