Here is the latest Caml Weekly News, for the week of 24 February to 02 March, 2004.
ECaml is a simple object system for OCaml, based on polymorphic variants and a Camlp4 syntax extension. ECaml can o create objects (entities) of anonymous class o create new classes within functions or other classes. o very easily define methods having polymorphic arguments NEWS: o Removed a bug resulting from the use of colon (:) as the method invocation operator. Of course this was conflicting with the type casting syntax, so now I am using the operator '#'. Users can still access methods on standard OCaml objects using the word "invoke" in place of '#'. o Added a way to concisely describe entity types, for module signatures.Jacques Garrigue said and Issac Trotts answered:
> Interesting. > I shall have a look at your encoding. It would be good to get your feedback on it. > You may also be interested by having a look at the current CVS version > of objective caml, because it actually has all the features you > describe. (This doesn't reduce your merit.) > Just a one line example: > Objective Caml version 3.07+13 (2004-01-04) > > # let o = object method id x = x end;; > val o : < id : 'a -> 'a > = <obj> This is very good to see. As far as I can tell, the OCaml object system can now do everything that ECaml can do. The only reason to use ECaml now would be if you are using an older version of OCaml (pre 3.07+13), or just to see an example of something fun to do with polymorphic variants and Camlp4. > And if you like experiments, you may even try the objvariants branch. > Just get the CVS version, and then do: > cvs update -r objvariants typing > It allows you to use unions of object types. > This is a quick hack (2 hours coding), and there may be bugs, but it > can be funny. Here is an example session. > > # let f (x : [> ]) = x#m 3;; > val f : [> as < m : int -> 'a; .. > ] -> 'a = <fun> > # let o = object method m x = x+2 end;; > val o : < m : int -> int > = <obj> > # f (`A o);; > - : int = 5 > # let l = [`A o; `B(object method m x = x -2 method y = 3 end)];; > val l : > [> `A of < m : int -> int > | `B of < m : int -> int; y : int > ] list = > [`A <obj>; `B <obj>] > # List.map f l;; > - : int list = [5; 1] > # let g = function `A x -> x#m 3 | `B x -> x#y;; > val g : [< `A of < m : int -> 'a; .. > | `B of < y : 'a; .. > ] -> 'a = <fun> > # List.map g l;; > - : int list = [5; 3] > > The type annotation (x : [> ]) is necessary: # is actually overloaded > on objects (the default) and variants of objects. You can view the > variant tag here a bit like a runtime type: you can pattern-match on > it when needed, but you can also call a method common to all cases > without looking at the tag. > > I got the idea in a paper (in Japanese) by Hideshi Nagira and Atsushi > Igarashi, but actually this trick was first suggested to me by Koji > Kagawa about 5 years ago. > > (Disclaimer: this kind of experiment is for fun, don't expect it in > the main branch anytime soon or ever.) I like it. Thanks for your message.
My company is looking for Caml riders and Caml breeders for internships and full time jobs in Milano, Italy. Anyone who is interested can send his or her CV to giorgia.spinola[ AT ]baretta[ dot ]com Thank you very much.
GODI, the O'Caml source distribution, has been updated with the following packages: - New versions of godi-tools (i.e. godi_console) and godi-core-mk. godi_console now includes a parser for makefiles that speeds up the process of scanning source packages. Furthermore, there are numerous bug fixes. - godi-ulex version 0.4 - conf-unixodbc and godi-ocamlodbc-unixodbc version 2.6 - godi-equeue version 2.0.1 - godi-findlib version 1.0.3 - conf-sdl and godi-ocamlsdl version 0.6.3 - godi-lablgl version 1.0 To install these packages, just go into the godi_console, get the new list of available packages, and select the mentioned packages for build. Note that you should exit godi_console and call it again to get the new version. Gerd GODI homepage: http://ocaml-programming.de/godi/
It is our pleasure to announce the first release of ocamlgraph, a graph library for ocaml. ocamlgraph intends to provide - several graph data strucures (persistent or imperative, labelled or not, directed or not, etc.) - several graph algorithms (shortest path, maximal flow, SCC, DFS, BFS, topological order, etc.) and graph operations (transitive closure, mirror, complement, union, intersection, random graph, random planar graph, etc.) Algorithms and operations are written independently of the graph data structrure (as functors) and thus can be easily reused in other contexts. Distribution and full API at http://www.lri.fr/~filliatr/ocamlgraph/ Comments and contributions are welcome.
I've put my small Extended thread synchronisations package in a new location as the old one was no longer available : http://www.linux-france.org/~dmentre/code/ This code provides barriers and read/write locks (with both reader and writer preference). The programing interface is a straightforward translation of the standard OCaml Thread and Mutex modules. License: GNU LGPL (same as OCaml standard library). The code is probably not much that complicated but still annoying to implement. Let me know if you find it usefull.
The following full-time tenure track position may interest some people on this list looking for a position in academia. I apologize for this not to be directly related to Ocaml but since a research theme is "Algorithms and Programming", language theorists are definitely welcome. The announce is in french because you need to be fluent enough in this language to apply. Please spread this announce around you. Thanks, ChriS ---------------------------------------------------------------------- L'Institut d'Informatique de l'Université de Mons-Hainaut souhaite vous informer de l'ouverture future d'une charge de cours à temps plein à partir du 1er octobre 2004. Les activités de recherche et d'enseignement se situeront en informatique, avec une préférence pour les domaines de l'"Algorithmique et Programmation" ou des "Réseaux et Télécommunications". Le candidat doit faire état d'une activité de recherche de haut niveau scientifique. Si vous souhaitez être informé au moment où cette vacance sera officialisée au moniteur, merci de manifester votre intérêt auprès du Prof. J. Wijsen (firstname.lastname@example.org). ---------------------------------------------------------------------- Mons is located on the highway Bruxelles-Paris near the French border. There is a direct train connection: Paris-Mons using Thalys (1h20, once a day). There are Faculties of Medicine, of Sciences, of Economics and Management, of Educational Sciences, an International School for foreign languages and a Polytechnic Faculty for engineering.
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