Mantra has a number of built-in types so far: object, int, char, string, list, dict, tree as well as some I/O objects.
There are no arrays in Mantra, only lists:
list names = ["Jim", "Ashar"];
Strings and ints etc.. are immutable but you can use mustring and mutint:
mutint i = mutint(34);
i++; println(i); mustring s = mustring("hi");
s += "mom";
println(s);
emits