(***********************************************************************) (* *) (* Caml Special Light *) (* *) (* Xavier Leroy, projet Cristal, INRIA Rocquencourt *) (* *) (* Copyright 1995 Institut National de Recherche en Informatique et *) (* Automatique. Distributed only by permission. *) (* *) (***********************************************************************) (* $Id$ *) (* Eratosthene's sieve *) (* interval min max = [min; min+1; ...; max-1; max] *) let rec interval min max = if min > max then [] else min :: interval (min + 1) max (* filter p L returns the list of the elements in list L that satisfy predicate p *) let rec filter p = function [] -> [] | a::r -> if p a then a :: filter p r else filter p r (* Application: removing all numbers multiple of n from a list of integers *) let remove_multiples_of n = filter (fun m -> m mod n <> 0) (* The sieve itself *) let sieve max = let rec filter_again = function [] -> [] | n::r as l -> if n*n > max then l else n :: filter_again (remove_multiples_of n r) in filter_again (interval 2 max) let rec do_list f = function [] -> () | a::l -> f a; do_list f l let _ = do_list (fun n -> print_int n; print_string " ") (sieve 40000); print_newline(); exit 0