I'm thinking of something like an interpreter, where each function implements one instruction and it does tail calls to go to the next instruction, instead of h

I'm thinking of something like an interpreter, where each function implements one instruction and it does tail calls to go to the next instruction, instead of having a giant switch statement in a loop. To match the implementation without tail calls, you probably don't want the previous instruction(s) on the stack, but all entry points into the interpreter should probably be on the stack.