const range = struct {
    start: usize,
    stepsz: usize,
    end: usize,

    fn init(start_: usize, stepsz_: usize, end_: usize) @This() {
        return range {
            .start = start_,
            .stepsz = stepsz_,
            .end = end_
        };
    }
    fn next(self: *@This()) ?usize {
        if (self.start + self.stepsz <= self.end) {
            var ret = self.start;
            self.start += self.stepsz;
            return ret;
        }
        return null;
    }

    fn size(self: *@This()) usize {
        return (self.end - self.start) / self.stepsz;
    }
};

pub fn main() void {
    comptime var sum: usize = 0;
    comptime {
        var r = range.init(0, 10, 100);

        while(r.next()) |val| {
            sum += val;
        }
    }

    @import("std").debug.warn("sum = {}\n", sum);
}