struct Range {
    a : int;
    b : int;
}
Range.metamethods.__for = function(iter,body)
    return quote
        var it = &iter
        while it.a < it.b do
            var i = it.a
            [body(i)]
            it.a = it.a + 1
        end
    end
end

terra foo()
    var a = 0
    -- This iterator is resumable, so you can break out of the loop and reenter.
    var iter = Range {0, 10}
    for i in iter do
        a = a + i
        break
    end
    for i in iter do
        a = a + i
        break
    end
    for i in iter do
        a = a + i
    end
    return a
end

assert(foo() == 10*9/2)