From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <daniel.buenzli@erratique.ch>
X-Original-To: caml-list@sympa.inria.fr
Delivered-To: caml-list@sympa.inria.fr
Received: from mail1-relais-roc.national.inria.fr (mail1-relais-roc.national.inria.fr [192.134.164.82])
	by sympa.inria.fr (Postfix) with ESMTPS id A39247ED34
	for <caml-list@sympa.inria.fr>; Tue,  3 Jul 2012 14:15:07 +0200 (CEST)
Received-SPF: None (mail1-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  daniel.buenzli@erratique.ch) identity=pra;
  client-ip=74.55.86.74;
  receiver=mail1-smtp-roc.national.inria.fr;
  envelope-from="daniel.buenzli@erratique.ch";
  x-sender="daniel.buenzli@erratique.ch";
  x-conformance=sidf_compatible
Received-SPF: None (mail1-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  daniel.buenzli@erratique.ch) identity=mailfrom;
  client-ip=74.55.86.74;
  receiver=mail1-smtp-roc.national.inria.fr;
  envelope-from="daniel.buenzli@erratique.ch";
  x-sender="daniel.buenzli@erratique.ch";
  x-conformance=sidf_compatible
Received-SPF: None (mail1-smtp-roc.national.inria.fr: no sender
  authenticity information available from domain of
  postmaster@smtp.webfaction.com) identity=helo;
  client-ip=74.55.86.74;
  receiver=mail1-smtp-roc.national.inria.fr;
  envelope-from="daniel.buenzli@erratique.ch";
  x-sender="postmaster@smtp.webfaction.com";
  x-conformance=sidf_compatible
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AnYCADbh8k9KN1ZKnGdsb2JhbABFhVqxMgEBAQEBCAsJCRQnghkBBSMEUhALGgImAgJHEAYbiAMEB6gIkzWBII8gMmADlkeEMRONDg
X-IronPort-AV: E=Sophos;i="4.77,515,1336341600"; 
   d="scan'208";a="165415671"
Received: from mail6.webfaction.com (HELO smtp.webfaction.com) ([74.55.86.74])
  by mail1-smtp-roc.national.inria.fr with ESMTP; 03 Jul 2012 14:15:06 +0200
Received: from [192.168.0.102] (5-232.197-178.cust.bluewin.ch [178.197.232.5])
	by smtp.webfaction.com (Postfix) with ESMTP id 7591D2113EA8;
	Tue,  3 Jul 2012 07:15:03 -0500 (CDT)
Date: Tue, 3 Jul 2012 14:14:59 +0200
From: =?utf-8?Q?Daniel_B=C3=BCnzli?= <daniel.buenzli@erratique.ch>
To: Ivan <ivg@ieee.org>
Cc: caml-list@inria.fr
Message-ID: <B7F0B3BD42684530A51B103D8A5B8757@erratique.ch>
In-Reply-To: <271211341286221@web29f.yandex.ru>
References: <271211341286221@web29f.yandex.ru>
X-Mailer: sparrow 1.6.1 (build 1081.52)
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Subject: Re: [Caml-list] howto: recursively iterate over filesystem

Hello, 

The book on Unix system programming in OCaml shows how to write a `find` function. 

    http://ocamlunix.forge.ocamlcore.org/files.html#htoc11

But if you don't need tight control over the process and don't want to link against the Unix module, just roll your own with the functions in Sys. 

That's what I usually use (note that it does follow symlinks). 

    val fold_files_rec : string list -> ('a -> string -> 'a) -> 'a -> 'a
    (** [fold_files_rec dirs f acc] lists the files in [dirs], recursively
         in depth first order and folds the function [f] over the file names. *)

    let fold_files_rec dirs f acc = 
      let readdir d = try Array.to_list (Sys.readdir d) with Sys_error _ -> [] in
      let is_dir d = try Sys.is_directory d with Sys_error _ -> false in
      let rec loop f acc = function
      | (d :: ds) :: up -> 
         let files = List.rev (List.rev_map (Filename.concat d) (readdir d)) in
         let dirs, files = List.partition is_dir files in
         let acc = List.fold_left f acc files in 
         loop f acc (dirs :: ds :: up)
      | [] :: [] -> acc
      | [] :: up -> loop f acc up
      | _ -> assert false
      in
      loop f acc (dirs :: []) 

Best,

Daniel