Here is the latest Caml Weekly News, for the week of June 16 to 23, 2009.
Archive: http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/b2d4360797f291c07400a4408db0d22a.en.htmlJun Furuse announced:
It is my pleasure to announce OCaml Meeting 2009 in Tokyo. In Japan, we have significant numbers of OCaml users. OCaml has been used for programming courses in several universities for years. We can read OCaml related blog posts written by people live in Japan everyday. We have even several Japanese books about programming in OCaml. But we have never met together. Now it is the time to meet up! OCaml Meeting 2009 in Tokyo will be the first OCaml specific conference in Japan: Date: 2009/08/30 (Sorry, it collides with ICFP unfortunately.) Place: the University of Tokyo, Sanjo Conference Hall Participation fee: Free! The meeting will be partially sponsored by - IT Planning, Inc. (http://www.itpl.co.jp/) - Jane Street Capital (http://www.janestreet.com) Its primary objective this time is to kick-start a local OCaml user community in Japan. Therefore talks will be mainly in Japanese and OCaml, but we welcome everyone interested in OCaml from everywhere. Further information will appear at the following sites: http://www.cocan.org/events (in English) http://ocaml.jp/?Users%20Meeting (in Japanese) For people who need further information, you can contact either me or Satoshi Ogasawara <ogasawara(a)itpl.co.jp>. We thank OCaml Meeting organization team of the past two OCaml Meetings in France, who has kindly permitted us to use the same name, "OCaml Meeting".
Archive: http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/85383174bb1b902c9413a752cb0f8bd0.en.htmlDavid MENTRE announced:
I'm pleased to announce that all OCaml packages made by Debian developers are now synchronized to OCaml 3.11.0 in Ubuntu Karmic: http://bentobako.org/ubuntu-ocaml-status/transition_monitor/ocaml_transition_monitor.html Moreover, all packages have the same version number in Debian Unstable and Ubuntu Karmic: http://bentobako.org/ubuntu-ocaml-status/raw/compare-unstable-karmic.html So Ubuntu Karmic, aka 9.10, to be released in October will ship with a full fledge OCaml 3.11.0! Many thanks to all Debian and Ubuntu developers involved. Regarding recently released OCaml 3.11.1, I'm not sure it will be ready for Karmic but it will be available in Karmic+1 and probably in a backport or through PPA. Sincerely yours, david  Except unison package, but the changes made in 2.27.57-2 revision should not impact users. http://packages.debian.org/changelogs/pool/main/u/unison/current/changelog#versionversion2.27.57-2
Archive: http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/8369429f41ab8e92250ad052a13f00aa.en.htmlConglun Yao asked, Pascal Rigaux said, and Sylvain Le Gall added:
> > I'm wondering is there any library in OCaml performing word inflection > > between singular and plural, like Lingua-EN-Inflect in perl. Or someone is > > already doing the work? > > not really comparable to Lingua-EN-Inflect, but if you want one day to > have i18n and you are under linux, ngettext is quite powerful. > cf http://www.gnu.org/software/hello/manual/gettext/Plural-forms.html > FYI, a pure OCaml implementation of ngettext, with plural support, can be found in ocaml-gettext: http://le-gall.net/sylvain+violaine/ocaml-gettext.htmlRichard Jones also suggested:
You should be able to call the perl module directly using perl4caml.
Archive: http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/e95c643956552bdc419820e0a3a81086.en.htmlGuillaume Yziquel said:
Please don't scream: I've been using Obj.magic... But the result is rather interesting. It can record a flow of computations, and recompute them only when upstream data has been modified: > # let (n', n) = Dependent.encapsulate 1;; > val n' : int Dependent.data = <abstr> > val n : int Dependent.t = <abstr> > # let (_, next) = Dependent.encapsulate (fun x -> x + 1);; > val next : (int -> int) Dependent.t = <abstr> > # let m = Dependent.apply next n;; > val m : int Dependent.t = <abstr> > # Dependent.access m;; > - : int = 2 > # Dependent.set n' 3;; > - : unit = () > # Dependent.access m;; > - : int = 4 The piece of code responsible for this behaviour is at the end of the message. I learnt that I could perhaps overcome the use of Obj.magic by using existential types. I was advised to read the following post on this topic: http://caml.inria.fr/pub/ml-archives/caml-list/2004/01/52732867110697f55650778d883ae5e9.en.html However, I do not really understand how Daniel implemented existential types there, and I do not really see how it can be adapted to my code. Suggestions welcomed. Here's the code, rather disorganised at the moment. All the best, Guillaume Yziquel. > type read;; > type write;; > > type 'a computation = (Obj.t -> 'a) t * Obj.t t > > and ('a, 'b) aux_t = Dependent of > ( 'a option ref * > 'a computation option * > Obj.t t list ref) > > and 'a data = ('a, write) aux_t > and 'a t = ('a, read) aux_t;; > > let encapsulate (x : 'a) : ('a data) * ('a t) = > let z = Dependent ((ref (Some x)), None, (ref )) in (z, z);; > > let add_dependency (alpha : 'a t) (beta : 'b t) = > let Dependent (_, _, dep) = alpha in > dep := ((Obj.magic beta) : Obj.t t)::!dep;; > > let apply (f : ('b -> 'a) t) (x : 'b t) : 'a t = > let computation : 'a computation = > ((Obj.magic f) : (Obj.t -> 'a) t), > ((Obj.magic x) : Obj.t t) in > let f_x : 'a t = Dependent ( > ((ref None) : 'a option ref), > ((Some computation) : 'a computation option), > ((ref ) : Obj.t t list ref)) in > add_dependency f f_x; > add_dependency x f_x; > f_x;; > > exception Undefined;; > > module rec Aux : > sig > > val access : 'a t -> 'a > val update : 'a t -> ('b -> 'a) t -> 'b t -> 'a > val reset : 'a t -> unit > > end = struct > > let rec access y = > let Dependent (opt_ref_x, comp_opt, _) = y in > match !opt_ref_x with | Some x -> x | None -> > begin match comp_opt with > | None -> raise Undefined > | Some (fun_t, arg_t) -> Aux.update y fun_t arg_t > end > > and update y fun_t arg_t = > let Dependent (opt_ref_x, _, dependencies) = y in > List.iter Aux.reset !dependencies; > let result = (Aux.access fun_t) (Aux.access arg_t) in > opt_ref_x := Some result; result > > and reset z = > let Dependent (opt_ref_x, _, dependencies) = z in > match !opt_ref_x with > | None -> () | Some _ -> begin > opt_ref_x := None; > List.iter Aux.reset !dependencies > end;; > > end;; > > include Aux;; > > exception Flawed_implementation;; > > let set (x : 'a data) (v : 'a) : unit = > let Dependent (opt_ref_x, comp_opt, dependencies) = x in > match comp_opt with | Some _ -> raise Flawed_implementation | None -> > begin List.iter Aux.reset !dependencies; > opt_ref_x := Some v > end;;Daniel Bünzli replied:
Not directly responding to your question but you are looking for functional reactive programming (frp). http://erratique.ch/software/react I rewrote your example below with react (no magic used). Best, Daniel > ocaml react.cmo Objective Caml version 3.11.0 # open React;; # let n, set_n = S.create 1;; val n : int React.signal = <abstr> val set_n : int -> unit = <fun> # let m = S.map (fun x -> x + 1) n ;; val m : int React.signal = <abstr> # S.value m;; - : int = 2 # set_n 3;; - : unit = () # S.value m;; - : int = 4Jake Donham also replied:
You can also find FRP in froc (which is quite similar to React; the main difference is that it works in browsers): http://code.google.com/p/froc/ # open Froc_afp;; # let n = return 1;; val n : int Froc_afp.t = <abstr> # let m = n >>= fun x -> return (x + 1);; val m : int Froc_afp.t = <abstr> # read m;; - : int = 2 # write n 3;; - : unit = () # propagate ();; - : unit = () # read m;; - : int = 4
Archive: http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/1a3f29c3afaf4d714c28573283cd5add.en.htmlYoriyuki Yamagata announced:
I'm happy to announce Camomile 0.7.2, new version of comprehensive Unicode library for Objective Caml. Changes are - License change: Add OCaml-style exception clause to LGPL license. - Small documentation fix to REAEME: Add cpp to the list of necessary GNU tools This will be a small step to Camomile Next Generation, I hope. After previous release, several people submitted patches (thanks!). I do not have time to incorporate them but are submitted patch-tracker (including patches sent by email) https://sourceforge.net/tracker/?group_id=40603&atid=428418 In addition, a new malinglist for discussion between Camomile users is open https://lists.sourceforge.net/lists/listinfo/camomile-users So, discuss and share tips for using of Camomile. I also want to hear who and what software use Camomile.He later added:
Ahem, I'm too hurry to post the article. It lacks the link to the package itself. Camomile is available from https://sourceforge.net/project/showfiles.php?group_id=40603&package_id=32800&release_id=691358
Thanks to Alp Mestan, we now include in the Caml Weekly News the links to the recent posts from the ocamlcore planet blog at http://planet.ocamlcore.org/. New HLVM examples: http://forge.ocamlcore.org/forum/forum.php?forum_id=390 FP-Syd #16.: http://www.mega-nerd.com/erikd/Blog/FP-Syd/fp-syd-16.html Finite maps galore: imperative code strikes back: http://eigenclass.org/R2/writings/finite-map-benchmarks Ubuntu 9.10 will ship with OCaml 3.11.0... for now: https://bentobako.org/david/blog/index.php?post/2009/06/18/Ubuntu-9.10-will-ship-with-OCaml-3.11.0...-for-now OCaml Monitor Applet: http://forge.ocamlcore.org/projects/omonitor-applet/ The Tree Nursery: http://alaska-kamtchatka.blogspot.com/2009/06/tree-nursery.html
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