OTOH parsing with a recursive descent parser requires either a machine with a stack and the approriate calling conventions OR a lot of work to fake it. FORTRANs

OTOH parsing with a recursive descent parser requires either a machine with a stack and the approriate calling conventions OR a lot of work to fake it. FORTRANs before F90 had no recursion (and you still have to explicitly declare that a function is recursive), and many early and easy architectures have no hardware stack.