> but the tail calls are integral to the function of the interpreter Not really, a trampoline could emulate them effectively where the stack won't keep growing

> but the tail calls are integral to the function of the interpreter Not really, a trampoline could emulate them effectively where the stack won't keep growing at the cost of a function call for every opcode dispatch. Tail calls just optimize out this dispatch loop (or tail call back to the trampoline, however you want to set it up).