Mattias Engdegård wrote:

let line_count filename =
  let f = open_in filename in
  let rec loop count =
    match (readline f) with
      | Some(_) -> loop (count+1)
      | None -> count in
  loop 0;;


Something like this should be even faster:

exception Done of int

let line_count file =
  let rec loop count =
    let _ =
      try
	input_line f
      with End_of_file -> raise (Done count)
    in
      loop (count + 1)
  in
    try loop 0 with Done x -> x

as it avoids unnecessary consing in the inner loop.

__

This should be a FAQ.

let line_count file =
    let rec loop count =
       let test =
          try
             let _ = input_line f in
             true
          with
          | Not_found -> false
       in
       if test then
          loop (count + 1)
       else
          count
    in
    loop 0
;;

No consing, no unnecessary try/catch, tail recursive.

Brian