A simple algorithm for constructing the sequence of prime numbers, in SML.

primes.sml

fun divisible x xs =
   case xs of
      [] => false
    | y::xs' => x mod y = 0 orelse divisible x xs'

fun primes lst =
   let fun acc(x, rest) =
      if divisible x rest then rest else x::rest
   in rev (foldl acc [] lst)
   end

fun from2 n =
   let fun aux (k, lst) = if k < 2 then lst else aux (k-1, k::lst)
   in aux (n, [])
   end

primes (from2 200)