> racket and guile has expanding stacks and doesn't have a recursion limit other than the whole memory of the computer I'm not familiar with how these two in p

> racket and guile has expanding stacks and doesn't have a recursion limit other than the whole memory of the computer I'm not familiar with how these two in particular work internally, but this may actually be more a side effect related to the implementation of call/cc than recursion. A popular technique is to truncate the stack when a continuation is captured. So you obviously need a stack that can expand.