I'm sort of hesitant to be "that guy", but I've seen this kind of thing be a bit of a trap before. The technique of simulating a stack on the heap is useful in

I'm sort of hesitant to be "that guy", but I've seen this kind of thing be a bit of a trap before. The technique of simulating a stack on the heap is useful in some situations, but it's very misleading to call it a form of safety. It's important to be clear about exactly what this buys you, and what it doesn't buy you. The benefit in a case like this is that you use memory a little more efficiently (since your stack frames contain exactly what you put in them) and you have a larger maximum size (since the heap tends to have more addressable space than the stack). This buys you more recursive depth (and therefore a larger input) before crashing. You can still run out of memory and crash. Arguably on systems like 64-bit Linux this is more dangerous, since the OOM killer is less predictable than stack overflow handling. Of course it is often worth it to be able to handle the input you happen to have on hand, but that's a functional improvement, not a safety improvement. It's no substitute for an algorithm that just uses less memory.