public static non_terminal find(String with_name){
  if (with_name == null)   return null;
 else   return (non_terminal)_all.get(with_name);
}

public static non_terminal find ( String with_name ) { if ( with_name == null ) return null ; else return ( non_terminal ) _all . get ( with_name ) ; }
lookup a non terminal by name string
