July 2002 - Haskell - Haskell.org

RE: foralls in class assertions
by Simon Peyton-Jones 22 Jul '02

22 Jul '02

Yes that looks plausible, though I assume you meant | class ( | Monad m, | forall a. Monoid (m a) | ) => MonadPlus m I.e. parens round the (m a). This business of having 'foralls' in a context (whether for a class or a function) is not hard to implement in principle, but in practice it'd take few days of hacking I guess. And, more to the point, thinking. What are the interactions with functional dependencies or implicit parameters? (Maybe none, but I've been caught before.) So it's really waiting for someone to say "having foralls in contexts would change my life and I would love you for ever", rather than "it'd be nice". Simon "lazy evaluation" PJ | -----Original Message----- | From: Ashley Yakeley [mailto:ashley@semantic.org] | Sent: 19 July 2002 03:24 | To: Simon Peyton-Jones; Haskell List | Subject: RE: foralls in class assertions | | | At 2002-02-20 13:15, Simon Peyton-Jones wrote: | | >OK, so it does look as though it's the same idea as | >that described in our paper. Good. | > | >I have not implemented, yet. | | I don't suppose you did for GHC 5.04?... | | >As always my implementation | >priorities are strongly influenced by my perception of whether some | >enhancement would be used. Maybe you can outline why such a change | >would be useful to you? I only have the example in our paper as | >motivation so far. | | I just thought of another motivating example for this: | | class Monoid a where | mempty :: a | mappend :: a -> a -> a | mconcat :: [a] -> a | | class ( | Monad m, | forall a. Monoid m a | ) => MonadPlus m | | Of course, you folks might not want to rewrite | Control.Monad.MonadPlus. | But I think is shows this sort of thing is useful in | principle (and it | would great for my HBase, which does its own Prelude). | | -- | Ashley Yakeley, Seattle WA | |

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COLOGNET Joint Workshop
by Manuel Carro 19 Jul '02

19 Jul '02

We apologize for multiple copies ========================================================================== Call for Papers and Participation --------------------------------- COLOGNET Joint Workshop on -------------------------- Component-based Software Development ------------------------------------ and Implementation Technology for Computational Logic Systems --------------------------------------------------------- (http://clip.dia.fi.upm.es/COLOGNET-WS/) Affiliated with LOPSTR 2002 19 - 20 September 2002, Madrid, Spain COLOGNET (http://www.colognet.org) the European Network of Excellence in Computational Logic is organizing a workshop on two of its workpackages: Component-based Software Development (CBD) and Implementation Technology for Computational Logic Systems (ITCLS). This joint workshop will be collocated with SAS/LOPSTR/AGP (http://clip.dia.fi.upm.es/SAS-LOPSTR-AGP) The aim of the workshop is to present and discuss current research issues, both in academia and industry. The joint workshop will be organized in two sessions: Component Based Software Development ------------------------------------ The goal of this session is to examine the process of component-based software development in all phases of the development life-cycle (i.e., specification, design, composition, testing, deployment). Special emphasis will be placed on the use of Computational Logic throughout the process. A non-exhaustive list of topics includes: - Methodological foundation of component-based software development. - Modeling of component-based systems. - Tools supporting component-based development. - Integration of the component paradigm into existing environments. - Component testing, verification, distribution, maintenance. - Combination of heterogeneous component technologies. - The role of Computational Logic in all the above. - Industrial experience reports. Implementation Technology for Computational Logic Programming ------------------------------------------------------------- This session is intended to be a continuation of the series of workshops on Implementations of Logic Programming Systems held in the context of COMPULOG NET, the former Network of Excellence in Computational Logic. But, in contrast to the COMPULOG area meetings on implementation, which were rather centered toward logic and constraint logic programming systems, the target of this workshop is broader: it includes implementation technology for other areas which are part of the COLOGNET network. The aim is to bring together researchers from fields such as automated reasoning, natural language processing, constraint logic programming, model checking, etc., in order to share common problems and solutions regarding implementation issues which arise in the logic-based systems arena. Suggested topics of interest for the implementation workshop include, but are not limited to: - Implementation of resolution and model elimination theorem provers. - Implementation for non-monotonic reasoning systems and semantics. - Implementation of higher-order, linear, etc. logics. - Implementation techniques for natural language processing. - Standard and non-standard sequential implementation schemes for constraint logic programing languages (e.g., generalization / modification of WAM, translation to C, etc.) - Memory management and garbage collection issues. - Implementation of concurrency and parallelism in logic-based languages. - Extensions to the Warren Abstract Machine. Term indexing. Invited Talks ------------- The workshop programme will consist of invited talks and accepted papers. So far, invited talks include the following: Keynote Speaker (shared among CBD, ITCLS and LOPSTR): ---------------------------------------------------- Robert Hall, AT & T (still pending of final confirmation). Robert Hall does research on Automated Software Engineering, particularly in making networked services and components secure, reliable, and scalable. CBD: ---- Antonio Brogi, University of Pisa, Modeling Component Behaviors. Kung-Kiu Lau, University of Manchester, A Priori Reasoning for CBD. Manuel Carro, UPM, Madrid, The AMOS Project. ITCLS: ------ Michael Fisher, University of Liverpool, Implementing Temporal Logics: Tools for Execution and Proof. Submissions and Deadlines ------------------------- Authors are invited to contribute to the programme by submitting extended abstracts (6 pages maximum) or full papers (12 pages maximum) on the workshop themes. Limits are strict, and the llncs format (http://www.springer.de/comp/lncs/authors.html) must be used. Submissions are to be sent to the organizing committee by emailing them to: - kung-kiu(a)cs.man.ac.uk (for CBD papers) or to - colognet-imp(a)clip.dia.fi.upm.es (for ITCLS papers) Submission deadline: July 26 Notification to authors: August 5 Camera-ready copies: September 5 Workshop: September 19-20 Informal proceedings will be available at the workshop. Organizing Committee -------------------- Antonio Brogi, University of Pisa, Italy. Manuel Carro, UPM, Madrid, Spain. Shui Ming Ho, University of Manchester, UK. Kung-Kiu Lau, University of Manchester, UK. Mario Ornaghi, University of Milan, Italy. German Puebla, UPM, Madrid, Spain. Claudio Vaucheret, UPM, Madrid, Spain. ===========================================================================

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RE: foralls in class assertions
by Ashley Yakeley 19 Jul '02

19 Jul '02

At 2002-02-20 13:15, Simon Peyton-Jones wrote: >OK, so it does look as though it's the same idea as >that described in our paper. Good. > >I have not implemented, yet. I don't suppose you did for GHC 5.04?... >As always my implementation >priorities are strongly influenced by my perception of whether >some enhancement would be used. Maybe you can outline >why such a change would be useful to you? I only have the >example in our paper as motivation so far. I just thought of another motivating example for this: class Monoid a where mempty :: a mappend :: a -> a -> a mconcat :: [a] -> a class ( Monad m, forall a. Monoid m a ) => MonadPlus m Of course, you folks might not want to rewrite Control.Monad.MonadPlus. But I think is shows this sort of thing is useful in principle (and it would great for my HBase, which does its own Prelude). -- Ashley Yakeley, Seattle WA

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Your message to Hugs-Users awaits moderator approval
by hugs-users-admin＠haskell.org 18 Jul '02

18 Jul '02

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another minor fault in the Haskell Report
by Malcolm Wallace 17 Jul '02

17 Jul '02

I have just discovered another minor fault in the revised Haskell'98 Report. In the definition of the Standard Prelude, (page 115) instance Read Float where readsPrec p = readFloat instance Read Double where readsPrec p = readFloat are incorrect because they do not deal with a leading minus sign. The correct versions are: instance Read Float where readsPrec p = readSigned readFloat instance Read Double where readsPrec p = readSigned readFloat Funnily enough, all the implementations seem to have this fix already, it is just the Report that gets it wrong! Regards, Malcolm

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会议提醒
by ee31＠163.com 16 Jul '02

16 Jul '02

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上海苑通计算机网络工程有限公司
by shanghaiyt＠163.com 13 Jul '02

13 Jul '02

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URGENT RESPONSE NEEDED
by MAXWELL EZE 13 Jul '02

13 Jul '02

REQUEST FOR URGENT /CONFIDENTIAL BUSINESSRELATIONSHIP. I am the Financial Controller, National Electric Power Authority (NEPA) here in Lagos, Nigeria. I am seeking for assistance of a reliable foreigner through whom I can transfer the sum of US$38,600.00(Thirty-Eight Million, Six Hundred Thousand U. S. Dollars) which arose from the deliberate over-inflated contract value of the general expansion of the Kanji Dam Thermal Station on behalf of National Electric Power Authority (NEPA) for increased energy generation to Nigeria and some other Western African Countries. The present government of chief Olusegun Obasanjo through the chairman contract award committee National Electric Power Authority awarded the contract to an expatriate firm with the consideration of 10% commission agreement on the total contract value. The contract has been completed and the contractor has long been paid, we are left with this US$38,600,000.00 being our own share that is remaining in the federal government account. The current favorable political / economic climate in the country now presented an opportunity for this money to be transferred out of the country. My contact in the federal ministry of finance have given me a go ahead advice to begin the process of the remittance, hence I have set in motion the machinery for the take off of this transaction and further actions will commence immediately I hear from you. At the conclusion of the transfer into your nominated account, 20% of this sum would be for you, 5% would be used to reimburse all expenses made during the processing of the transfer by both parties, while 75% is for me. The nature of your business is not particular relevant for the transaction. All I require is your willingness to co-operate and assurance that my own share will be given to me when this money is transferred into your account. All necessary precautions have been taken to ensure a no risk situation on the sides of both parties and it is believed that this conclusion of this transaction will not last more than 14 working days. Since I have no knowledge of business, my plan is to invest this money into real estate, stock and I can also invest in some other profitable business in your country based on your advice because many of my years has been spent as civil servant, and I may likely resign from government service to private business after this money is transferred into your account. Please if this proposal is acceptable to you, or if you have any questions feel free to contact me on the above e-mail address. I will oblige you with further information and please I need your private telephone/fax numbers, for easy and confidential communication. Best regards, MAXWELL EZE

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12 Jul '02

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C2hs compilation error
by Kenny Lu Zhuo Ming 12 Jul '02

12 Jul '02

Hi, When I try to compile my HS code with some open source C code using C2HS 0.10.14, I encountered this error, c2hs --cppopts='-I/home/luzm/sphinx2-0.4/include/ -pedantic' listener.h Listener.chs c2hs: Generic fatal error. /usr/include/gconv.h:172: (column 3) [FATAL] >>> Syntax error! The symbol `__extension__' does not fit here. Can someone tell me when it probably goes wrong? Thanks in advance! Kenny

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