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ucuz arama
by NETTEALO 05 Jul '03

05 Jul '03

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Worldwide Partners program
by The TechNews 05 Jul '03

05 Jul '03

The TechNews, July 2003 Production Mini-plants in mobile containers. Worldwide Partners program Science Network will supply to countries and developing regions the technology and necessary support for production in series of Mini-plants in mobile containers (40-foot). The Mini-plant system is designed in such a way that all the production machinery is fixed on the platform of the container, with all wiring, piping, and installation parts; that is, they are fully equipped... and the mini-plant is ready for production." More than 700 portable production systems: Bakeries, Water purification, Dehydrated food, Steel Nails, Fruit juice preparation, Tire Retreading, Reinforcement Bar Bending for Construction Framework, Sheeting for Roofing, Ceilings and Façades, Plated Drums, Aluminum Buckets, Injected Polypropylene Housewares, Pressed Melamine Items (Glasses, Cups, Plates, Mugs, etc.), Mufflers, Construction Electrically Welded Mesh, Plastic Bags and Packaging, Mobile units of medical assistance, Sanitary Material, Hypodermic Syringes, Hemostatic Clamps, etc. Science Network has started a Co-investment program for the installation of small Assembly plants to manufacture in series the Mini-plants of portable production on site, region or country where required. One of the most relevant features is the fact that these plants will be connected to the World Trade System (WTS) with access to more than 50 million raw materials, products and services and automatic transactions for world trade. Due to financial reasons, involving cost and social impact, the best solution is setting up assembly plants on the same countries and regions, using local resources (labor, some equipment, etc.) Science Network participates at 50% (fifty percent) for investment of each Assembly plant. If you are interested in being a Science Network partner in your country or region, you can send your CV to: Mini-plants <A HREF="mailto:letters@the-tech-news.com">Worldwide Partners program</A> By Robert B. Lethe, The TechNews, Editor ------------------------------------------------------------------------- If you received this in error or would like to be removed from our list, please return us indicating: remove or un-subscribe in subject field, Thanks. <A HREF="mailto:editor@the-tech-news.com"> Editor</A> © 2003 The TechNews. All rights reserved.

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FFI Ptr question
by paul＠theV.net 03 Jul '03

03 Jul '03

If a C function returns a (void*), let's say: data MyObj = MyObj foreign import ccall "static myobj_ffi.h new_obj" newMyObject :: IO (Ptr MyObj) ptr <- newMyObject should I free the ptr afterwards or not? If I have another imported C function: foreign import ccall "static myobj_ffi.h print_obj" printMyObject :: Ptr MyObj -> IO () Can I safely assume the C function print_obj(void *) always get the same pointer even if I call (printMyObject ptr) multiple times? Any hints is greatly appreciated! Regards, .paul.

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by webmaster 03 Jul '03

03 Jul '03

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RE: haskell array access
by Simon Peyton-Jones 01 Jul '03

01 Jul '03

| Are there any concoctions of flags/pragmas/techniques to coax GHC into | unrolling a function (or rather an IO computation in this case) a couple | of iterations. There was another (admittedly also noddy) program that I | could get to near gcc, but only by unrolling by hand (though Ian's TH | stuff likely could have done it). GHC generally doesn't unroll recursions. The inliner runs repeatedly, so it's hard for it to know how much it unrolled "last time". (There's a paper "Secrets of the GHC inliner" on my publications page.) Simon

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UML diagrams of Haskell
by Bas van Dijk 30 Jun '03

30 Jun '03

Hi, It's maybe a weird question but do there exist UML diagrams of the Haskell language. They don't necessarily have to be UML diagrams, as long as they show the different concepts in the language (i.e.: functions, datatypes, patterns, etc.) and the relations between them(i.e.: a function consists of other functions, functions have a type). Bas.

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RE: Arrow Classes
by Simon Peyton-Jones 30 Jun '03

30 Jun '03

It may interest you guys to know that Ross Paterson and I have just put syntactic support for arrows into GHC. It's only in the CVS version at the moment, and is not documented at all, but those things will come. The type error messages should, I hope, be a lot better than those one can get by type checking pre-processed code. Simon | -----Original Message----- | From: haskell-cafe-admin(a)haskell.org [mailto:haskell-cafe-admin@haskell.org] On Behalf Of Joe | English | Sent: 28 June 2003 17:01 | To: haskell-cafe(a)haskell.org | Subject: Re: Arrow Classes | | | Ashley Yakeley wrote: | > Wolfgang Jeltsch wrote: | > | > > This brings me to another point. One year ago we had a discussion on The | > > Haskell Mailing List concerning arrows. (The subject of the mails was just | > > "arrows".) The point was that it seemed strange to me that first and second | > > are included in the basic arrow class Arrow while left and right have their | > > extra class ArrowChoice. Not only that it seemed strange to me but it made | > > impossible to make Parser baseMonad an instance of Arrow. Parser baseMonad | > > has nice implementations of pure and (>>>) but none of first or second. | > | > I agree. My own Arrow module hierarchy looks more or less like this: | > | > class Compositor comp where [...] | > class (Compositor arrow) => Arrow arrow where [...] | > class (Arrow arrow) => ProductArrow arrow where [...] | > class (Arrow arrow) => CoproductArrow arrow where [...] | > class (ProductArrow arrow,CoproductArrow arrow) => FullArrow arrow | > instance (ProductArrow arrow,CoproductArrow arrow) => FullArrow arrow | > class (Arrow arrow) => ArrowFix arrow where [...] | > class (FullArrow arrow) => ApplyArrow arrow where [...] | | | On that topic, see below for what mine looks like | (from HXML, <URL: http://www.flightlab.com/~joe/hxml/ >). | | I started off with Hughes' conventions, but for some | reason could never remember the difference between &&& and ***, | or between ||| and +++. I found &&&, >&<, |||, >|< to have | better mnemonic value. This also frees up +++ for ArrowPlus, | which -- in HXML applications -- is frequently used and should | thus be easy to type. | | When using the ArrowChoice operators, I kept tripping over all | the 'Either' coproduct types, so added some syntactic sugar | (borrowed from HaXML): | | data Choice a = a :> a | class (Arrow a) => ArrowChoice a where | [ ... ] | ( ?>) :: (b -> Bool) -> Choice (a b c) -> a b c | (>?>) :: a b Bool -> Choice (a b c) -> a b c | | I found "p ?> f :> g" much more pleasant to use. | | (I also like the idea of splitting the product operators out of | the base Arrow class -- will consider doing that in my library). | | -- | | infixr 5 +++ | infixr 3 >&<, &&& | infixr 2 >|<, |||, ?>, >?>, :> | infixl 1 >>> | | class Arrow a where | arr :: (b -> c) -> a b c | (>>>) :: a b c -> a c d -> a b d | apfst :: a b c -> a (b,x) (c,x) | apsnd :: a b c -> a (x,b) (x,c) | (>&<) :: a b c -> a d e -> a (b,d) (c,e) | (&&&) :: a b c -> a b d -> a b (c,d) | liftA2 :: (b -> c -> d) -> a e b -> a e c -> a e d | aConst :: c -> a b c | idArrow :: a b b | -- Minimal implementation: arr, >>>, apfst or >&< | | data Choice a = a :> a | class (Arrow a) => ArrowChoice a where | apl :: a b c -> a (Either b d) (Either c d) | apr :: a b c -> a (Either d b) (Either d c) | (>|<) :: a b c -> a d e -> a (Either b d) (Either c e) | (|||) :: a b c -> a d c -> a (Either b d) c | ( ?>) :: (b -> Bool) -> Choice (a b c) -> a b c | (>?>) :: a b Bool -> Choice (a b c) -> a b c | -- Minimal implementation: >|< or apl | | class (Arrow a) => ArrowApply a where | app :: a (a b c,b) c | | class (Arrow a) => ArrowZero a where | aZero :: a b c | aMaybe :: a (Maybe c) c | aGuard :: (b -> Bool) -> a b b | | class (Arrow a) => ArrowPlus a where | (+++) :: a b c -> a b c -> a b c | | | | --Joe English | | jenglish(a)flightlab.com | _______________________________________________ | Haskell-Cafe mailing list | Haskell-Cafe(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe

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RE: UML diagrams of Haskell
by Hal Daume 30 Jun '03

30 Jun '03

There's something like UML, called FAD (Functional Analysis and Design, I believe). It was the topic of Daniel Russell's PhD thesis. See http://www.cs.kent.ac.uk/pubs/2001/1152/index.html for more. -- Hal Daume III | hdaume(a)isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume > -----Original Message----- > From: haskell-cafe-admin(a)haskell.org > [mailto:haskell-cafe-admin@haskell.org] On Behalf Of Bas van Dijk > Sent: Sunday, June 29, 2003 2:50 PM > To: HaskellCafe Mailinglist > Subject: UML diagrams of Haskell > > > Hi, > > It's maybe a weird question but do there exist UML diagrams > of the Haskell > language. > They don't necessarily have to be UML diagrams, as long as > they show the > different concepts in the language (i.e.: functions, > datatypes, patterns, > etc.) and the relations between them(i.e.: a function > consists of other > functions, functions have a type). > > Bas. > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >

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RE: Simple monads
by Hal Daume 29 Jun '03

29 Jun '03

> (a) People could point out to me where I'm still confused, as > revealed by > my code. Is it needlessly complicated? looks pretty reasonable to me :) as to why Unique is in the IO monad is probabyl because if it were in any other monad, you could start the monad twice and thus get a repeat of each ID (if that makes sense). The only way around this is to put it in IO.

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Bom dia haskell-cafe
by Marta 29 Jun '03

29 Jun '03

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