Question

Suppose I have this function, in pseudo-code, that reverse a list:

def function reverse( list ) :
if ( empty(list) ) 
    return empty_list;
else 
    return append( 
        reverse( list(2, lenght) , 
                 list(1)));

This code is not tail-recursive;
how can i make it tail-recursive?

Answer 1

See: Tail Call

For F#

let map f l =
    let rec loop acc = function
        | [] -> List.rev acc
        | x::xs -> loop (f x::acc) xs
    loop [] l

For reversing a string