private boolean evaluateCameraClause(String str) {
		if (str == null || str.equals(""))
			return false;
		double x = parseMathExpression(str);
		if (Double.isNaN(x))
			return false;
		view.setCameraAtom((int) Math.round(x));
		view.repaint();
		model.notifyChange();
		return true;
	}