Here is the latest Caml Weekly News, for the week of 26 October to 09 November, 2004.
Archive: http://caml.inria.fr/archives/200410/msg00314.htmlTiago Dionizio asked:
I was playing with ocaml (learning!) and bumped with something that i think it might be a bug... since i didn't find anything explaining this behaviour: Objective Caml version 3.08.0 # print_string "**e";; e- : unit = () # print_char '*';; - : unit = () # it seems that the '*' char is ignored at the beginning of the lines on the windows gui, the same does -not- happen on the command line version. Is this a known problem? Sorry if this was reported already or if it a known issue.Christopher A. Watford fixed the problem and replied:
As always, if you want the bleeding edge of OCamlWinPlus, I suggest you check out (that is my actual VS.Net project directory): http://projects.tunkeymicket.com/OCamlWinPlus/Release/ If you'd like the more stable side of the bleeding edge (stable directory on my webserver that only takes polished copies): http://dorm.tunkeymicket.com/OCamlWinPlus/Release/
Archive: http://caml.inria.fr/archives/200410/msg00343.htmlBrian Hurt announced:
I've created a new mailing-list/yahoo group ocaml-licensing, for a discussion of the pros and cons of various licenses for Ocaml code. The URL is here: http://groups.yahoo.com/group/ocaml-licensing/ Or send email to: email@example.com There is now an official elsewhere to take this dicussion. Thank you.
Archive: http://caml.inria.fr/archives/200410/msg00350.htmlGerd Stolpmann announced:
The GODI project has a new homepage explaining how to install and use the source code O'Caml distribution: http://godi.ocaml-programming.de Highlights are: - An online version of the new GODI manual - Lists with available packages - Collection of the most important O'Caml links The new GODI manual is also available as GODI package godi-manual. It explains almost every aspect of the GODI installation in detail. Furthermore, there is also documentation of package creation (with the GODI core method; GODIVA is not (yet?) explained). I hope the homepage and the manual make GODI a bit more transparent, and also more attractive.
Archive: http://caml.inria.fr/archives/200410/msg00363.htmlNicolas Cannasse announced:
I'm please to announce the first release of SwfLib, a pure OCaml library for parsing, manipulating, and writing SWF content. SWF is the file format used by Macromedia Flash Player and available on most users browsers. It contains a vector draw engine with bitmaps support and have a simple stack based virtual machine for a dynamic OO scripting language called ActionScript. SwfLib can both produce the graphics and the bytecode needed to build a SWF binary file. SWFLib source code is released under GPL, and is currently only available on CVS using the following CVSROOT : cvs -d :pserver:firstname.lastname@example.org:/cvsroot co ocaml/swflib With empty password.
Archive: http://caml.inria.fr/archives/200410/msg00371.htmlJohn Harrison asked and William Lovas answered:
> Is there a way to use the OCaml module system to declare an > abstract type with an implementation as a recursive type in > such a way that: > > * You can use the constructors to pattern-match against > > * You cannot use the constructors to construct values Indeed, there is! The relevant keyword is `private'. See: http://email@example.com for details. > For example, suppose I do the following: > > module type Wibble = > sig type thing = Integer of int | Boolean of bool > val mk_thing : int -> thing > val dest_thing: thing -> int > end;; > > module Thing : Wibble = struct > type thing = Integer of int | Boolean of bool > let mk_thing i = Integer i > let dest_thing t = match t with > Integer i -> i > | Boolean b -> if b then 1 else 0 > end;; > > include Thing;; > > I can now define functions by pattern-matching, which I want: > > fun (Boolean b) -> b;; > > but I can also use the constructors to construct, which I don't: > > Integer(3);; > > On the other hand, if I change the signature to just > > module type Wibble = > sig type thing > val mk_thing : int -> thing > val dest_thing: thing -> int > end;; > > then I can do neither. Is there any way to get one and not the > other? In your example, we just do: > For example, suppose I do the following: > > module type Wibble = > (* sig type thing = Integer of int | Boolean of bool *) sig type thing = private Integer of int | Boolean of bool > val mk_thing : int -> thing > val dest_thing: thing -> int > end;; > > [...] And then it works as expected: # Thing.Integer 5;; Cannot create values of the private type Thing.thing # let thing = Thing.mk_thing 5;; val thing : Thing.thing = Thing.Integer 5 # match thing with Thing.Integer i -> i | Thing.Boolean b -> 0;; - : int = 5
Archive: http://caml.inria.fr/archives/200410/msg00269.htmlFollowing this library announcement, the following took place:
Owen Gunden wrote: > Julien Signoles wrote: > > Richard Jones wrote: > > > I'm pleased to announce GregorianDate [...] > > > > What are the differences with the module Date of the "calendar" library ? > > > > http://www.lri.fr/~signoles/prog.en.html > > I've a stake in this question too, as the maintainer for the calendar > godi package. It sure would be nice if the effort was merged into one > UberCalendar so there would be no question which package to use. Ah, sorry - this discussion moved to ocaml-lib-devel. I cc'd caml-list, but it seems to have been spam filterered. http://sourceforge.net/mailarchive/forum.php?thread_id=5833296&forum_id=29880
Archive: http://caml.inria.fr/archives/200410/msg00384.htmlDiego Olivier Fernandez Pons asked and Nicolas Cannasse answered:
> I would like a Caml program to output some information to an output > channel and according to my needs this channel be redirected to > - a (human readable) file > - the standard output > - a black hole > > The "general output functions" section of Pervasives seem to be what I > need but it hasn't the same signature than "Output functions on > standard output" Generic IO from ExtLib are dealing with this problem, and have a printf functionnality. They also have useful functions such as write_i16 / write_ui32 .... (in low and big endian) when dealing with C binary files. > I suspect I could just compose with string_of_X functions to obtain > the same result. There is also an awful [fprintf] function inherided > from C but I am still trying to understand the doc (never understood > C's either). printf "%d %f %s %c" 33 1.234 "hello" 'x' > Why haven't the equivalent functions been added to the standard lib to > allow a drop in replacement ? Maybe because printf allows you to specify precision for int/floats as well as newlines ?
Archive: http://caml.inria.fr/archives/200410/msg00388.htmlMaxence Guesdon announced:
The contents of the Mozcaml sidebar has been updated (at least!) for ocaml 3.08. Mozcaml is a sidebar for Mozilla dedicated to the Caml language. It provides direct access to many information about Objective Caml: news, user's manual, library documentation and the humps (the collection of links to Caml-related stuff). Each of these sources can be browsed throughout several views, including contents tree, indexes or search engines. Mozcaml: http://caml.inria.fr/mozcaml/
Archive: http://caml.inria.fr/archives/200410/msg00404.htmlYamagata Yoriyuki announced:
Camomile 0.6.1 is released. This release is intended to be a bug-fix only release. Fixed bugs are * the bug that "get" methods of polymorphic input channels have the type 'a, which should be unit -> 'a. * a bug which causes flush methods of octet output channels only flush 1024*n bytes at a time. * Remove a superfluous check from configure. You can download the new release from http://prdownloads.sourceforge.net/camomile/camomile-0.6.1.tar.bz2?download Our Web page is http://camomile.sourceforge.net/ Please submit your bug report to the bug tracker. http://sourceforge.net/tracker/?atid=428416&group_id=40603&func=browse GODI version will be released in the next days. Camomile is a Unicode library for ocaml. Camomile provides Unicode character type, UTF-8, UTF-16, UTF-32 strings, conversion to/from about 200 encodings, collation and locale-sensitive case mappings, and more.
Archive: http://caml.inria.fr/archives/200410/msg00406.htmlYamagata Yoriyuki announced:
Surreal library is again available from http://www15.ocn.ne.jp/~rodinia/surreal.html Unfortunately, no improvement has been possible (yet). Logarithm and reverse triangular functions are not implemented. Surreal library is an exact real arithmetic library for OCaml. The goal is to do middle-scale computation with 500-2000 operands to exact reals in the reasonable amount of time. To that goal, surreal uses some heuristics to evaluate the value of reals, with optimized algorithms for transcendental functions. By using Numerix, surreal avoids memory allocation overhead, since Numerix uses OCaml heap allocator and GC directly for all memory management
Archive: http://caml.inria.fr/archives/200411/msg00006.htmlMartin Sandin:
I'm pleased to announce that the first release of Ochra, v0.1, is now available. The release and information is available at: http://www.guldheden.com/~sandin/ochra Ochra is a syntax extension for OCaml, extending the language with explicit support for programming using an Object-Oriented Reference Attributed Grammar (RAG) formalism. The primary intended use is for compiler construction. It introduces a new kind of classes, called productions, which support a number of extra features for specifying AG node children and attributes. Ochra is modeled on JastAdd, a compiler construction tool which extends Java. Ochra is however a less intrusive addition than JastAdd, which along with RAG support also introduces Aspect Orientation in Java. Ochra instead relies on the more powerful modularization mechanisms of OCaml (multiple inheritance, structural subtyping, parametrized types and modules, ...), compared to Java, to provide the same level of modularity. JastAdd has been used to construct, among other things, a Java compiler and is used in compiler classes at Lund Institute of Technology. Comments are ofcourse appreciated:) Ochra is released under the LGPL license with the same exceptions as for the OCaml libraries.
Archive: http://caml.inria.fr/archives/200411/msg00046.htmlJohn Skaller:
I have just uploaded a revised tarball for Felix 1.0.18. Felix is open source with BSD style FFAU licence. http://felix.sf.net/downlooad/flx_1.0.18_src.tgz This version now incorporates the Scheme interpreter ocs-1.0 in the compiler. Ocs was written by Ville-Pertti Keinonen <firstname.lastname@example.org> and the original source can be obtained from URL http://will.iki.fi/software/ocs/ A scheme reference can be found at http://www.schemers.org/Documents/Standards/R5RS/HTML/ The interpreter is available standalone tool (called 'ocs_main' at the moment, but the name will probably change) It can also be used with the Felix preprocessor. #scheme (display "//generated by scheme\n") #scheme (load "somefile.sch") The environment is currently shared across directives and include files so variables set in one place can be used in subsequent places. The #scheme directive is replaced by whatever it writes to standard output, and is then tokenised as if it were Felix code. In future releases I may add system variables and utilities to the environment, and perhaps extend the interpreter so it can access some of the compiler state. I will be examining whether it is feasible to invert the control relation of the front end so it's a scheme program embedding Ocaml (rather than the other way arond). This may help to make user control and extensions easier to script.
Archive: http://caml.inria.fr/archives/200411/msg00035.htmlAaron Bohannon asked and Xavier Leroy answered:
> I was quite surprised, recently, when I found out that the native code > compiler implements left-to-right evaulation, as opposed to the > right-to-left evaulation of the bytecode. This isn't quite right. The native-code compiler is essentially neutral w.r.t. evaluation order, meaning that it can implement any given evaluation order without singificant changes or performance impact. However, following the principle of least surprise, it tries to enforce the same evaluation order as the bytecode compiler, that is, right-to-left. There is one mistake in 3.08 (corrected in the main branch) that causes left-to-right evaluation for arguments to certain inlined functions (see PR#2910). If you observe left-to-right evaluation with ocamlopt, please report it. It's not really a bug according to the OCaml manual (which leaves evaluation order undefined), but it's certainly a "quality of implementation" issue that we'd like to be aware of. > You see, I am quite familiar with the ZINC machine and the benefits of > its design, and I thought that the design could be adapted in some way > or another to the native code setting. I am interested in finding out > what factors prevented this, or what made the ZINC machine execution > model impractical in the native runtime. My knowledge of systems is > perhaps somewhat weak, so maybe I am overlooking some obvious point. The ZINC / OCaml VM handling of curried function application (an instance of the push-enter model) pretty much requires that parameters are passed on a stack. For native code generation, it is much more efficient to pass the first N parameters in processor registers. This doesn't fit the ZINC model at all.
Archive: http://caml.inria.fr/archives/200411/msg00048.htmlDavid McClain asked and Xavier Leroy answered:
> I just obtained a new iMac G5 here. My cursory understanding is that this is > a 64 bit core processor. However, when I attempted to run config for > rebuilding the OCaml system, it reports a 32 bit system. What can or must I > do to coax OCaml to become a 64 bit system for this processor? As others have explained, the first thing you need is a 64-bit kernel and a development environment (C compiler, linker, libraries) that handles 64-bit code. The next release of Mac OS X is rumored to offer all this. Once this is available, you should be able to compile the bytecoded part of OCaml to 64-bit code using e.g. configure -cc "gcc -m64" or whatever gcc options that select the generation of 64-bit apps. However, ocamlopt will not work out of the box. Some changes to the asm code generator are required to produce 64-bit code. In the case of the PowerPC, the changes are relatively small. Still, I can't perform them until we have G5 machines at INRIA, which may take a while. (Pretty much the only Apple hardware we buy are Powerbooks, and it's unclear when G5 Powerbooks will be mainstream.) Also, the only situations where 64-bit code is beneficial are 1- large integer arithmetic (bignums, crypto), and 2- exploiting more than 4 Gb of RAM. In all other cases, 64-bit code is actually a waste, since pointers occupy twice as much memory as with 32-bit code. So, I expect 64-bit computing to take off when machines commonly have 4 Gb of RAM or more, which should take a few more years. Caml will have no problems adapting to this trend, since it's 64-bit clean from the start. (Caml Special Light, the ancestor of OCaml, was developed circa 1995 on a 64-bit Alpha, then backported to 32-bit architectures.) I expect that at that time our "tier 1" architectures will be x86-64 and PPC-64.
Archive: http://caml.inria.fr/archives/200411/msg00031.htmlWolfgang Müller asked and Yoann Padioleau answered:
> I would like to print values to a file in a human-readable manner without > having to compose the output writers of print_int and friends. In short, I > would like to use the toplevel's function for screen output of structured > values. I recently post a message to allow this (with generic print in the subject of the message). the code is available at: http://www.irisa.fr/prive/padiolea/hacks/generic_print.ml example: let _ = print_string (generic_print [[1;3];[2;9;8];[3;4]] "int list list" in let _ = print_string (generic_print [1;3;2;9;8;3;4] "int list") in ... test: ./test_generic ==> [[1; 3]; [2; 9; 8]; [3; 4]] [1; 3; 2; 9; 8; 3; 4]Daniel Bünzli added:
Although research oriented you may want to have a look at acute, an extension of an ocaml core to support, among other things, type safe value IO : http://www.cl.cam.ac.uk/users/pes20/acute/
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