public ClassCalc(String filename) throws IOException {
		try{
			load(new BufferedReader(new FileReader(filename)));
		}catch(FileNotFoundException e2) {
			System.out.println(filename + " not found");
		}
	}

        private load(BufferedReader r) throws IOException {
		while(true){
                        String s = r.readLine();
                        if (s != null) {
                              eval(s);
                        } else {
                               break;
                        }
                }

         }