A range that iterates over elements of the container from index i up to (excluding) index j.
Precondition: i <= j && j <= length.
auto v = Array!int([1, 2, 3]); auto r = v[]; assert(r.front == 1); assert(r.back == 3); r.popFront(); assert(r.front == 2); r.popBack(); assert(r.back == 2); assert(r.length == 1);
auto v = Array!int([1, 2, 3, 4]); auto r = v[1 .. 4]; assert(r.length == 3); assert(r[0] == 2); assert(r[1] == 3); assert(r[2] == 4); r = v[0 .. 0]; assert(r.length == 0); r = v[4 .. 4]; assert(r.length == 0);