* [Caml-list] Hashtable, possible?
@ 2003-05-24 19:52 Lukasz Lew
2003-05-25 0:34 ` Remi Vanicat
0 siblings, 1 reply; 6+ messages in thread
From: Lukasz Lew @ 2003-05-24 19:52 UTC (permalink / raw)
To: caml-list
Hi.
Is it possible to implement with camlp4, syntax for using hashtables like
arrays?
I think about something like this:
# let a = [{ }];;
val a : ('_a, '_b) Hashtbl.t = <abstr>
# a.{"foo"} <- 'f';;
- : unit = ()
I need only "yes" or "no" :)
Regards,
Lukasz Lew
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Caml-list] Hashtable, possible? 2003-05-24 19:52 [Caml-list] Hashtable, possible? Lukasz Lew @ 2003-05-25 0:34 ` Remi Vanicat 2003-05-25 0:48 ` Remi Vanicat 0 siblings, 1 reply; 6+ messages in thread From: Remi Vanicat @ 2003-05-25 0:34 UTC (permalink / raw) To: caml-list Lukasz Lew <ll189417@zodiac.mimuw.edu.pl> writes: > Hi. > Is it possible to implement with camlp4, syntax for using hashtables like > arrays? > I think about something like this: > > # let a = [{ }];; > val a : ('_a, '_b) Hashtbl.t = <abstr> > > # a.{"foo"} <- 'f';; > - : unit = () > > I need only "yes" or "no" :) yes it is -- Rémi Vanicat vanicat@labri.u-bordeaux.fr http://dept-info.labri.u-bordeaux.fr/~vanicat ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Hashtable, possible? 2003-05-25 0:34 ` Remi Vanicat @ 2003-05-25 0:48 ` Remi Vanicat 2003-05-25 13:40 ` Lukasz Lew 0 siblings, 1 reply; 6+ messages in thread From: Remi Vanicat @ 2003-05-25 0:48 UTC (permalink / raw) To: caml-list Remi Vanicat <vanicat@labri.u-bordeaux.fr> writes: > Lukasz Lew <ll189417@zodiac.mimuw.edu.pl> writes: > >> Hi. >> Is it possible to implement with camlp4, syntax for using hashtables like >> arrays? >> I think about something like this: >> >> # let a = [{ }];; >> val a : ('_a, '_b) Hashtbl.t = <abstr> >> >> # a.{"foo"} <- 'f';; >> - : unit = () >> >> I need only "yes" or "no" :) > > yes it is well, you should use something else than [{ }] and a.{ ... } because they already have a meaning, but if you find something then yes you can. -- Rémi Vanicat vanicat@labri.u-bordeaux.fr http://dept-info.labri.u-bordeaux.fr/~vanicat ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Hashtable, possible? 2003-05-25 0:48 ` Remi Vanicat @ 2003-05-25 13:40 ` Lukasz Lew 2003-05-25 13:50 ` Eray Ozkural 2003-05-26 1:15 ` Jacques Garrigue 0 siblings, 2 replies; 6+ messages in thread From: Lukasz Lew @ 2003-05-25 13:40 UTC (permalink / raw) To: Remi Vanicat; +Cc: caml-list On Sun, 25 May 2003, Remi Vanicat wrote: > Remi Vanicat <vanicat@labri.u-bordeaux.fr> writes: > > > Lukasz Lew <ll189417@zodiac.mimuw.edu.pl> writes: > > > >> Hi. > >> Is it possible to implement with camlp4, syntax for using hashtables like > >> arrays? > >> I think about something like this: > >> > >> # let a = [{ }];; > >> val a : ('_a, '_b) Hashtbl.t = <abstr> > >> > >> # a.{"foo"} <- 'f';; > >> - : unit = () > >> > >> I need only "yes" or "no" :) > > > > yes it is > > well, you should use something else than [{ }] and a.{ ... } because > they already have a meaning, but if you find something then yes you > can. thank you all. So. If it is possibe, and there is such syntax for arrays, strings and bigarrays, so why there isn't any for hashtables? I belive hashtables are more often used than bigarrays... Lukasz Lew ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Hashtable, possible? 2003-05-25 13:40 ` Lukasz Lew @ 2003-05-25 13:50 ` Eray Ozkural 2003-05-26 1:15 ` Jacques Garrigue 1 sibling, 0 replies; 6+ messages in thread From: Eray Ozkural @ 2003-05-25 13:50 UTC (permalink / raw) To: Lukasz Lew, Remi Vanicat; +Cc: caml-list On Sunday 25 May 2003 16:40, Lukasz Lew wrote: > thank you all. > > So. If it is possibe, and there is such syntax for arrays, strings and > bigarrays, so why there isn't any for hashtables? > I belive hashtables are more often used than bigarrays... Why don't you write one for yourself? It would also be good p4 practice. Be careful not to do something that looks like something else in mathematics though. That's how I would go about it. Happy hacking, -- Eray Ozkural (exa) <erayo@cs.bilkent.edu.tr> Comp. Sci. Dept., Bilkent University, Ankara KDE Project: http://www.kde.org www: http://www.cs.bilkent.edu.tr/~erayo Malfunction: http://mp3.com/ariza GPG public key fingerprint: 360C 852F 88B0 A745 F31B EA0F 7C07 AE16 874D 539C ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Hashtable, possible? 2003-05-25 13:40 ` Lukasz Lew 2003-05-25 13:50 ` Eray Ozkural @ 2003-05-26 1:15 ` Jacques Garrigue 1 sibling, 0 replies; 6+ messages in thread From: Jacques Garrigue @ 2003-05-26 1:15 UTC (permalink / raw) To: ll189417; +Cc: caml-list From: Lukasz Lew <ll189417@zodiac.mimuw.edu.pl> >> Is it possible to implement with camlp4, syntax for using hashtables like >> arrays? [...] > So. If it is possibe, and there is such syntax for arrays, strings and > bigarrays, so why there isn't any for hashtables? > I belive hashtables are more often used than bigarrays... Maybe, but code using hash tables does not access/modify them several times on the same line... There is also a reasonnable concern about not having too many fancy notations in the language. Last, as ocaml does not use camlp4 by default, the answer to your question would not imply that this is possible in ocaml alone. However, if you are not using bigarrays, you can actually reuse their notation in the vanilla compiler, by just defining the following module: # module Bigarray = struct module Array1 = struct let set = Hashtbl.add let get = Hashtbl.find end end;; module Bigarray : sig module Array1 : sig val set : ('a, 'b) Hashtbl.t -> 'a -> 'b -> unit val get : ('a, 'b) Hashtbl.t -> 'a -> 'b end end # let f x y z = x.{y} <- z;; val f : ('a, 'b) Hashtbl.t -> 'a -> 'b -> unit = <fun> # let g x y = x.{y};; val g : ('a, 'b) Hashtbl.t -> 'a -> 'b = <fun> However you probably also want sugar for hash table creation, and this would indeed require camlp4: {|"a" => 1; "b" => 2|} But you can still do a lot with simple functions: # let (=>) x y = (x,y);; val ( => ) : 'a -> 'b -> 'a * 'b = <fun> # let hash l = let h = Hashtbl.create (max 7 (List.length l)) in List.iter (fun (k,d) -> h.{k} <- d) l; h;; val hash : ('a * 'b) list -> ('a, 'b) Hashtbl.t = <fun> # let h = hash["a"=>1;"b"=>2];; val h : (string, int) Hashtbl.t = <abstr> # h.{"a"};; - : int = 1 --------------------------------------------------------------------------- Jacques Garrigue Kyoto University garrigue at kurims.kyoto-u.ac.jp <A HREF=http://wwwfun.kurims.kyoto-u.ac.jp/~garrigue/>JG</A> ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2003-05-26 1:15 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2003-05-24 19:52 [Caml-list] Hashtable, possible? Lukasz Lew 2003-05-25 0:34 ` Remi Vanicat 2003-05-25 0:48 ` Remi Vanicat 2003-05-25 13:40 ` Lukasz Lew 2003-05-25 13:50 ` Eray Ozkural 2003-05-26 1:15 ` Jacques Garrigue
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