Describe what is meant by tail recursion

Compiler Construction Programming answers should be written in some notation approximating SML or OCaml. (a) Describe what is meant by tail recursion. [4 marks] (b) Eliminate tail recursion from foldl given below. Explain your answer. (* foldl : (‘a -> ‘b -> ‘a) -> ‘a -> ‘b list -> ‘a *) let rec foldl f accu l = match l with [] -> accu | a::l -> foldl f (f accu a) l [8 marks] (c) Eliminate tail recursion from the following mutually tail-recursive functions. Explain your answer. let rec is even n = if n = 0 then true else is_odd (n – 1) and is_odd n = if n = 0 then false else is even(n – 1) [8 marks] 4