void open(int contextPrec,int ownPrec) throws IOException {
  if (ownPrec < contextPrec)   out.write("(");
}

void open ( int contextPrec , int ownPrec ) throws IOException { if ( ownPrec < contextPrec ) out . write ( "(" ) ; }
enter a new precedence level . emit a ` ( ' if new precedence level is less than precedence level so far .
