ocaml/camlp4/ocaml_src/lib/fstream.ml

82 lines
1.7 KiB
OCaml

(* camlp4r *)
(* This file has been generated by program: do not edit! *)
(* Copyright 2001 INRIA *)
type 'a t = { count : int; data : 'a data Lazy.t }
and 'a data = Nil | Cons of 'a * 'a t | App of 'a t * 'a t
;;
let from f =
let rec loop i =
{count = 0;
data =
lazy
(match f i with
Some x -> Cons (x, loop (i + 1))
| None -> Nil)}
in
loop 0
;;
let rec next s =
let count = s.count + 1 in
match Lazy.force s.data with
Nil -> None
| Cons (a, s) -> Some (a, {count = count; data = s.data})
| App (s1, s2) ->
match next s1 with
Some (a, s1) -> Some (a, {count = count; data = lazy (App (s1, s2))})
| None ->
match next s2 with
Some (a, s2) -> Some (a, {count = count; data = s2.data})
| None -> None
;;
let empty s =
match next s with
Some _ -> None
| None -> Some ((), s)
;;
let nil () = {count = 0; data = Lazy.lazy_from_val Nil};;
let cons a s = Cons (a, s);;
let app s1 s2 = App (s1, s2);;
let flazy f = {count = 0; data = Lazy.lazy_from_fun f};;
let of_list l =
List.fold_right (fun x s -> flazy (fun () -> cons x s)) l (nil ())
;;
let of_string s =
from (fun c -> if c < String.length s then Some s.[c] else None)
;;
let of_channel ic =
from
(fun _ ->
try Some (input_char ic) with
End_of_file -> None)
;;
let iter f =
let rec do_rec strm =
match next strm with
Some (a, strm) -> let _ = f a in do_rec strm
| None -> ()
in
do_rec
;;
let count s = s.count;;
let count_unfrozen s =
let rec loop cnt s =
if Lazy.lazy_is_val s.data then
match Lazy.force s.data with
Cons (_, s) -> loop (cnt + 1) s
| _ -> cnt
else cnt
in
loop 0 s
;;