[Haskell] Control.Monad.Writer as Python generator
Hi, I was thinking to myself: What in Haskell would give me a "yield" command like a Python generator? And the answer was "tell" in Control.Monad.Writer -- and I wrote some simple examples (see below). Most Python code using yield would be translated to something much more idiomatic in Haskell than using Writer, or to something more complicated if it needed IO. I thought this interesting enough to put on the haskell mailing list and wiki since it seemed to be in neither place (I searched, but your searching may be better than mine). If there are no objections then I'll put this example on the wiki; any suggestions where on wiki to place it (e.g. MonadWriter)? === CUT HERE === import Control.Monad.Writer -- Some type signatures would need -fglasgow-exts to compile -- We only care about the Writer output, not the function return value asGenerator :: Writer [a] v -> [a] asGenerator writer = values where (_,values) = runWriter writer --yield :: (MonadWriter [a] m) => a -> m () yield x = tell [x] -- This allows several items to be yielded with one command --yieldMany :: (MonadWriter [a] m) => [a] -> m () yieldMany = tell zeros :: [Integer] zeros = asGenerator (do yield 0 yield 0 yield 0) zerosInf :: [Integer] zerosInf = asGenerator zeros' where zeros' = (yield 0 >>zeros') -- The Collatz sequence function foo :: (Integral a) => a -> a foo x = case (x `mod` 2) of 0 -> x `div` 2 1 -> (3*x+1) -- Uses "return ()" to end the list when 1 is reached --collatzW :: (MonadWriter [a] m, Integral a) => a -> m () collatzW x = do yield x case x of 1 -> return () _ -> collatzW (foo x) -- Keeps going, will repeat "1,4,2,1,.." if 1 is reached --collatzInfW :: (MonadWriter [a] m, Integral a) => a -> m t collatzInfW x = do yield x collatzInfW (foo x) --collatzGen :: (MonadWriter [a] (Writer [a]), Integral a) => a -> [a] collatzGen x = asGenerator (collatzW x) --collatzInfGen :: (MonadWriter [a] (Writer [a]), Integral a) => a -> [a] collatzInfGen x = asGenerator (collatzInfW x) -- And these can be combined collatz1 x = asGenerator (collatzW x >> yield 0 >> collatzW (x+1)) === CUT HERE === *Main> zeros [0,0,0] *Main> take 10 zerosInf [0,0,0,0,0,0,0,0,0,0] *Main> collatzGen 13 [13,40,20,10,5,16,8,4,2,1] *Main> take 100 $ collatzInfGen 13 [13,40,20,10,5,16,8,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2, 1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2, 1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1,4,2,1] *Main> collatz1 12 [12,6,3,10,5,16,8,4,2,1,0,13,40,20,10,5,16,8,4,2,1] ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] pretty printing Haskell code with auto parens?
On Tue, Apr 12, 2005 at 06:33:13PM -0700, Conal Elliott wrote: > No reply yet. > > Alternatively, does anyone happen to have a HsExp->HsExp (for > Language.Haskell.Syntax) pass that inserts disambiguating parentheses as > needed, to be applied just before pretty-printing? There is one included in 'hatchet' which I have succescfully reused in other projects. A bug is that it doesn't refix infix patterns, but that should be easy to fix. http://www.cs.mu.oz.au/~bjpop/hatchet.html You will probably have to write something to collect fixities from imported modules. -- John Meacham - ârepetae.netâjohnâ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
RE: [Haskell] pretty printing Haskell code with auto parens?
No reply yet. Alternatively, does anyone happen to have a HsExp->HsExp (for Language.Haskell.Syntax) pass that inserts disambiguating parentheses as needed, to be applied just before pretty-printing? Cheers, - Conal -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Conal Elliott Sent: Friday, April 08, 2005 3:54 PM To: haskell@haskell.org Subject: [Haskell] pretty printing Haskell code with auto parens? What pretty printers are available for Haskell code (not necessarily complete) that handle automatic insertion of minimally required parentheses? I assumed that Language.Haskell.Pretty did that, but apparently it relies on manual insertion of parentheses in the abstract syntax. Thanks, - Conal ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Post-doc position in Martin Odersky's group, EPFL, Switzerland
EPFL Lausanne Programming Methods Group Prof. Martin Odersky We have an open position for a postdoctoral researcher in the Programming Methods Group at EPFL. The research of our group is centered on Scala, a new programming language which fuses functional and object-oriented programming and which interoperates at the same time with Java and .NET. Scala pushes the state of the art in type systems for component abstractions and composition. It also provides many new concepts for web programming. Here are some of our current research directions: - Further developments in the Scala language design - High-level optimizations - Type systems for object-oriented and functional languages - Programming language support for XML - Component technology. - Reliable software, verification, testability. If you work in some of these research areas and are interested in both system building and theory, you will find an active and friendly research environment at Lausanne. The appointment is for one year initially with renewals possible up to three years. The position is open from June, 2005, but later starting dates can also be considered. Compensation is competitive at CHF 80K+ (1 CHF ~~ 0.83 U.S$), depending on age and experience. Informal inquiries about the position may be addressed to [EMAIL PROTECTED] Formal applications should be sent by e-mail to the following address: Mme Yvette Dubuis [EMAIL PROTECTED] Tel. +41 21 693 5202 Fax +41 21 693 6660 To be guaranteed full consideration, applications should be received by May 15th, 2000. Applications should consist of a curriculum vitae, a publication list, and the names of three personal references. Please ask your references to send their letters directly to [EMAIL PROTECTED] EPFL Lausanne is one of two federal universities in Switzerland. It has one of the most nationally diverse research, teaching and learning communities in Europe. Lausanne is situated in very attractive surroundings in the French-speaking part of Switzerland, on the shore of Lake Geneva, in close proximity to the Alps. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] GTTSE Summer School: Early registration deadline April 15
This is a reminder that the deadline for early registration for the Summer School on Generative and Transformational Techniques in Software Engineering (GTTSE 2005), to be held in Braga, Portugal, from July 4 to 8, 2005, is: *** Early Registration Deadline: April 15, 2005 *** Online registration can be done via the GTTSE website at: http://www.di.uminho.pt/GTTSE2005 For more details, please consult the website or the call for participation below. -- Dr. ir. Joost Visser | Departamento de Informática phone +351-253-604461 | Universidade do Minho fax+351-253-604471 | mailto:[EMAIL PROTECTED] mobile +351-91-6253618 | http://www.di.uminho.pt/~joost.visser - Summer School on Generative and Transformational Techniques in Software Engineering 4 - 8 July, 2005, Braga, Portugal http://www.di.uminho.pt/GTTSE2005 SCOPE AND FORMAT The summer school brings together PhD students, lecturers, technology presenters, as well as other researchers and practitioners who are interested in the generation and the transformation of programs, data, models, meta-models, and documentation. This concerns many areas of software engineering: software reverse and re-engineering, model-driven approaches, automated software engineering, generic language technology, to name a few. These areas differ with regard to the specific sorts of meta-models (or grammars, schemas, formats etc.) that underly the involved artifacts, and with regard to the specific techniques that are employed for the generation and the transformation of the artifacts. The tutorials are given by renowned representatives of complementary approaches and problem domains. Each tutorial combines foundations, methods, examples, and tool support. The program of the summer school also features invited technology presentations, which present setups for generative and transformational techniques. These presentations complement each other in terms of the chosen application domains, case studies, and the underlying concepts. Furthermore, the program of the school also features a participants workshop. All students of the summer school will be invited to give a presentation about their ongoing work. They will be asked to submit a title and an abstract beforehand. The senior researchers present at the summer school will provide the students with feedback on their presentations. All summer school material will be collected in proceedings that are handed out to the participants. Formal proceedings will be compiled after the summer school, where all contributions are subjected to additional reviewing. The formal proceedings will be published in the Lecture Notes in Computer Science series of Springer. TUTORIALS * Don Batory (The University of Texas at Austin): Feature Oriented Programming * Ira Baxter (Semantic Designs Inc.): Compiling Fast XML reader/writers from DTDs using Program Transformations * Jean Bezivin (INRIA, LINA, University of Nantes): Metamodelling and Model Driven Software Development * Shigeru Chiba (Tokyo Institute of Technology): Program Transformation With Reflective and Aspect-Oriented Programming * Jean-Luc Hainaut (University of Namur): The Transformational Approach to Database Engineering * Zhenjiang Hu (University of Tokyo): Program Optimization and Transformation in Calculational Forms * Erik Meijer (Microsoft, Redmond): Object, relational, and XML mapping * Tom Mens (University of Mons-Hainaut): On the Use of Graph Transformations for Model Refactoring TECHNOLOGY PRESENTATIONS The purpose of the technology presentations is to supplement the theoretical knowledge acquired in the tutorials with practical knowledge of how generative and transformational tool support can be instrumental in solving software engineering problems. Technology presentations can include, but are not limited to demonstration of the features of a single tool. Rather, they include: * Reference to the concepts behind the technology * Application of the technology to a case study of non-trivial scale * Clear statement of benefits and limitations of the technology The participants will have ample opportunity to interact in informal manner with the technology presenters. Confirmed technology presentations: (Note: titles and authors abbreviated) * Mark van den Brand (CWI & HvA, The Netherlands) et al.: Applications of the ASF+SDF Meta-Environment * Martin Bravenboer (Utrecht University, The Netherlands) et al.: Domain-specific Language Embedding using Stratego/XT and MetaBorg * Thomas R. Dean (Queen's University, Canada): Applications of Agile Parsing To Web Services * Helena Galhardas (IST Tagus Park, Portugal): Data cleaning and transformation using te AJAX framework * Dirk Heuzeroth (sd&m AG, Germany) et al.: A Tool Suite for Invasive Software Composition * Frederic Jouault (UniversitÈ de Nantes, France): Model Transformation and Weaving Tools in the AMMA Platform * Guenter Kniesel (University of Bonn): Refactoring based on Co
[Haskell] Second Call for Papers for International Workshop on Foundations of Software Engineering (FSEN'05)
Our apologies if you have received multiple copies. - Second Call for Papers IPM International Workshop on Foundations of Software Engineering (FSEN 2005) 1-3 October 2005, Tehran, Iran. http://cs.ipm.ac.ir/FSEN05 FSEN 2005 is an international workshop organized by the Institute for Studies in Theoretical Physics and Mathematics (IPM) in Iran (http://www.ipm.ac.ir). Workshop goals -- The aim of the workshop is to bring together researchers and practitioners working on different aspects of formal methods in software engineering. The specific goal is to facilitate transfer of experience, adaptation of methods, and where possible, collaboration between different groups. The topics may cover any aspect in formal methods, especially those related to advancing the application of formal methods in software industry and promoting their integration with practical engineering techniques. Topics of interest -- The topics of this workshop include, but are not restricted to, the following: * Models of programs and systems * Software specification, validation and verification * Software architectures and their description languages * Object and multi-agent systems * Coordination and feature interaction * Integration of formal and informal methods * Integration of different formal methods * Component-based development * Service-oriented development * Model checking and theorem proving * Software and hardware verification * CASE tools and tool integration * Application to industrial cases Proceedings --- Accepted papers will be available at the workshop in a pre-proceedings published by IPM. A post-proceedings will be published in the Elsevier's ENTCS conference series. Selected papers will also be published in a special issue of a journal (to be confirmed). Best Paper Award There will be an award for the best paper. Important Dates --- * June 1, 2005: Submissions deadline * July 15, 2005: Notification of authors * August 1, 2005: Camera ready copies deadline * October 1-3, 2005: FSEN workshop Submissions --- The length of each paper including figures and references must not exceed the maximum size of 15 ENTCS style pages. All papers must be submitted in PDF or postscript format. Papers are to be sent to the following email address: [EMAIL PROTECTED] Submissions should explicitly state their contribution and their relevance to the theme of the workshop. Other criteria for selection will be originality, significance, correctness, and clarity. Simultaneous or similar submissions to other conferences or journals are not allowed. Workshop Chair -- Ali Movaghar Sharif University of Technology, Iran IPM, Iran PC Chairs - Farhad Arbab CWI, Netherlands Leiden University, Netherlands University of Waterloo, Canada Marjan Sirjani Tehran University, Iran IPM, Iran Local Organization Chair Marjan Sirjani Tehran University, Iran IPM, Iran Program committee - * Farhad Arbab - CWI, Netherlands; Leiden University, Netherlands; University of Waterloo, Canada * Mohammad Ardeshir - Sharif University of Technology, Iran * Christel Baier - University of Bonn, Germany * Frank de Boer - CWI, Netherlands; Leiden University, Netherlands * Marcello Bonsangue - Leiden University, Netherlands * Franck van Breugel - York University, Canada * James C. Browne - Texas University, USA * Michael Butler - University of Southampton, UK * Marsha Chechik - University of Toronto, Canada * Dennis Dams - Bell Labs, USA * Nancy Day - University of Waterloo, Canada * Maurizio Gabbrielli - University of Bologna, Italy * Yuri Gurevich - Microsoft Research, USA * Joost Kok - Leiden University, Netherlands * Marta Kwiatkawska, University of Birmingham, UK * Mohammad Reza Meybodi - AmirKabir University of Technology, Iran * Seyyed Hassan Mirian - Sharif University of Technology, Iran * Ali Movaghar - Sharif University of Technology, Iran; IPM, Iran * Andrea Omicini - University of Bologna, Italy * George Papadopoulos - University of Cyprus, Cyprus * Willem-Paul de Roever - University of Kiel, Germany * Jan Rutten - CWI, Netherlands; Vrije University Amsterdam, Netherlands * Mohsen Sharifi, Iran University of Science and Technology, Iran * Sandeep Shukla- Virginia Tech, USA * Marjan Sirjani - Tehran University, Iran; IPM, Iran * Alan Wassyng - McMaster University, Canada Invited Speakers (to be confirmed) ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/ma
[Haskell] Formal Methods 2005: Call for Participation
(With apologies for multiple copies) Formal Methods 2005 (FM'05) 18-22 July 2005 Newcastle upon Tyne, UK First Call for Participation www.csr.ncl.ac.uk/fm05 It is our pleasure to invite you to attend FM'05, the leading international conference for researchers and practitioners in formal methods for the development of computing systems. This year, the conference is being held at the University of Newcastle upon Tyne, UK on 18-22 July. Formal methods continue to have a major impact on systems and software engineering, especially in areas where dependability, security and trust matter. FM'05 aims to publish the latest developments of interest to researchers and practitioners alike. The outstanding programme of tutorials and workshops (listed overleaf) covers the range from circuit design, through high integrity programming to fault tolerance, architectures and automated reasoning. Wednesday 20th July is a special Industry Day, with a series of invited talks on experiences of formal methods going mainstream. The programme of around 30 research papers, announced in mid-April, will provide an opportunity to get up to date in all these areas and more. Alongside the tutorials, workshops and research symposium, there will be displays of tools, products, research projects and publishers. FM'05 is being held in one of England's most dynamic cities, famous for its captivating welcome, and situated at the heart of an historic and beautiful region. There will be plenty of opportunity for informal discussion: social activities include a reception at the Hatton Gallery and conference dinner in Alnwick Castle and Gardens. We look forward to welcoming you to Newcastle in July! John Fitzgerald, General Chair Ian Hayes, Andrzej Tarlecki, Programme Chairs TO REGISTER download a registration form from www.csr.ncl.ac.uk/fm05 or contact the Organiser: Claire Smith, Tel: +44 (0) 191 222 7999 Fax: +44 (0) 191 222 8788 Email:[EMAIL PROTECTED] --- --- --- --- --- --- --- --- OUTLINE OF EVENTS Full Scientific Programme 20-22 July Invited Speakers: Mathai Joseph (Tata Research & Development, Pune, India) Marie-Claude Gaudel (Université de Paris-Sud, France) Chris Johnson (University of Glasgow, UK) Industry Day 20 July: Formal Methods Going Mainstream - Costs, Benefits and Experiences contributions from Microsoft, Intel, Embedded Systems Institute, ETH Zürich and Verum Consultants. Industry Day is sponsored by SAP Research. Co-located Conferences (18-19 July): Calculemus 2005 Formal Aspects of Security and Trust (FAST) 2005 Workshops (18-19 July): Grand Challenge Workshop on Dependable Systems Evolution Web Languages and Formal Methods (WLFM 2005) Overture - the future of VDM and VDM++ Practical Applications of Stochastic Modelling (PASM 2005) Workshop on Rigorous Engineering of Fault Tolerant Systems (REFT 2005) The Railway Domain (TRain 2005) Tutorials (18-19 July): The Spec# Programming System: an Overview Formal Aspects of Software Architecture Increasing Dependability of Smart Card Based Systems Perfect Developer SPARK Petri-nets and Role Models as Intermediate Level Tools for Asynchronous Circuit & Systems Design Verifying Industrial Control System Software Formal Engineering Methods for Industrial Software Development Modelling Languages Spectrum Formal Methods as a Unifying Basis for Electrical and Computer Engineering Design by Contract and Automatic Verification for Java with JML and ESC/Java 2 Introduction to CSP and FDR TO REGISTER download a registration form from www.csr.ncl.ac.uk/fm05 or contact the Organiser: Claire Smith, Tel: +44 (0) 191 222 7999 Fax: +44 (0) 191 222 8788 Email:[EMAIL PROTECTED] ___ events mailing list [EMAIL PROTECTED] http://www.fmeurope.org/mailman/listinfo/events ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
