diff options
| author | Daniel de Rauglaudre <daniel.de_rauglaudre@inria.fr> | 2001-09-07 07:32:09 +0000 |
|---|---|---|
| committer | Daniel de Rauglaudre <daniel.de_rauglaudre@inria.fr> | 2001-09-07 07:32:09 +0000 |
| commit | 14075dda1789ce74afb083bd8cf75edb567ea457 (patch) | |
| tree | 84a6d8428df672d27dc80142e2d413f45ebf275c /camlp4/ocaml_src/lib/fstream.ml | |
| parent | 4cb19c456f421a28be378fcb169fb10346990253 (diff) | |
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git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@3706 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Diffstat (limited to 'camlp4/ocaml_src/lib/fstream.ml')
| -rw-r--r-- | camlp4/ocaml_src/lib/fstream.ml | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/camlp4/ocaml_src/lib/fstream.ml b/camlp4/ocaml_src/lib/fstream.ml new file mode 100644 index 000000000..de5ba0572 --- /dev/null +++ b/camlp4/ocaml_src/lib/fstream.ml @@ -0,0 +1,79 @@ +(* camlp4r *) +(* Id *) +(* 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 = ref (Lazy.Value Nil)};; +let cons a s = Cons (a, s);; +let app s1 s2 = App (s1, s2);; +let flazy f = {count = 0; data = ref (Lazy.Delayed 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 = + match !(s.data) with + Lazy.Value (Cons (_, s)) -> loop (cnt + 1) s + | _ -> cnt + in + loop 0 s +;; |