function __TS__Iterator(iterable)
    if iterable[Symbol.iterator] then
        local iterator = iterable[Symbol.iterator](iterable)
        return function()
            local result = iterator:next()
            if not result.done then
                return result.value
            else
                return nil
            end
        end
    else
        local i = 0
        return function()
            i = i + 1
            return iterable[i]
        end
    end
end

for char in __TS__Iterator("foo") do
    print(char)
end

function __TS__Iterator(iterable)
    if iterable[Symbol.iterator] then
        local iterator = iterable[Symbol.iterator](iterable)
        return function()
            local result = iterator:next()
            if not result.done then
                return result.value
            else
                return nil
            end
        end
	elseif type(iterable) == "string" then
        local i = 0
        return function()
            i = i + 1
            return string.sub(iterable, i, i)
        end
    else
        local i = 0
        return function()
            i = i + 1
            return iterable[i]
        end
    end
end

for char in __TS__Iterator("foo") do
    print(char)
end