static Category category(Object x){
	Class xc = x.getClass();

	if(xc == Integer.class)
		return Category.INTEGER;
	else if(xc == Double.class)
		return Category.FLOATING;
	else if(xc == Long.class)
		return Category.INTEGER;
	else if(xc == Float.class)
		return Category.FLOATING;
	else if(xc == BigInt.class)
		return Category.INTEGER;
	else if(xc == Ratio.class)
		return Category.RATIO;
	else if(xc == BigDecimal.class)
		return Category.DECIMAL;
	else
		return Category.INTEGER;
}