static String _sum = "${sum;<list>[;<list>...]}";
public String _sum(String args[]) throws Exception {
verifyCommand(args, _sum, null, 2, Integer.MAX_VALUE);
List<String> list = toList(args, 1, args.length);
double d = 0;
for (String s : list) {
double v = Double.parseDouble(s);
d += v;
}
return toString(d);
}