June 2021 - Haskell-Cafe

How to debug HSC to HS conversion failure?
by David Banas 23 Jun '21

23 Jun '21

I’m getting the following error in response to `cabal build`: running {pros_dir}/dist-newstyle/build/x86_64-osx/ghc-8.8.4/haskarchpriv-0.1.0.0/build/HaskArch/TLM2_hsc_make failed (exit code -11) rsp file was: “{proj_dir}/dist-newstyle/build/x86_64-osx/ghc-8.8.4/haskarchpriv-0.1.0.0/build/HaskArch/hsc2hscall86171-3.rsp" My project contains one *.hsc file, which is the target of the error above. How can I debug the cause of this? The “rsp” file is nowhere to be found; what is(was) it? And, is it a helpful debugging aid? If so, is there an option I can give, to preserve it? Thanks! -db

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Is anyone running regular virtual Haskell hacking events?
by Chris Smith 23 Jun '21

23 Jun '21

I'm thinking of ideas, and wondering if anyone's beat me to this one. Before COVID-19, I organized a "co-hack" with the New York Haskell User Group one Saturday per month, where people would get together and write or discuss Haskell for several hours. I always had a great time, but... then COVID-19. Does something like this exist online? If not, I was just looking at Zoom, and realized they have breakout rooms where people can divide up and separately talk in groups. I was thinking of setting up an event something like this: Start: 9am Pacific / 12pm Eastern / 4pm GMT / 6pm CET - 15 minute intro and logistics - 30 minute Small group intros. Divide people up randomly into small groups to introduce themselves and talk about their Haskell stories and what they are working on. About 4-5 people per group (because 2 people feels too small, but too many people means shy people are afraid to speak up.) - 30 minute lightning talks and project pitches: Maybe 5 minutes / 3 slides max, sign up in advance or jump in and do a talk impulsively - 2.5 hours project time. Use for working together on projects, pair programming, teach and learn Haskell, etc. Use Zoom breakout groups and let people hop from room to room as desired. Pre-create some rooms for common activities (like "Beginner Questions", "Project Euler", etc.) Create some generic rooms people can jump in as they like for short collaborations. Create persistent project-specific rooms on demand. - 15 minute wrap-up. Finish: 1pm Pacific / 4pm Eastern / 8pm GMT / 10pm CET What does everyone think? I don't see any reason this couldn't go really well. The Cohack in New York was really fun, and I'd like to give it a shot. Anyone else motivated to help run this? If I can get at least one co-facilitator, I'll jump in and make it happen. I'll spring for the Zoom account. Probably use Meetup to take signups and manage scheduling, unless someone has another preference. Thanks, Chris Smith

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Final Call for Talks: Haskell Implementors' Workshop @ ICFP'21
by Ningning Xie 23 Jun '21

23 Jun '21

Final Call for Talks ACM SIGPLAN Haskell Implementors' Workshop https://icfp21.sigplan.org/home/hiw-2021 Virtual, 22 Aug, 2021 Co-located with ICFP 2021 https://icfp21.sigplan.org/ New: Invited Speaker -------------------- Title: Haskell reinterpreted – large-scale real-world experience with the Mu compiler in Financial Markets Speaker: Bengt Marten Agren, Standard Chartered Bank Important dates --------------- Deadline: Wednesday, 30 June, 2021 (AoE) Notification: Wednesday, 14 July, 2021 Workshop: Sunday, 22 August, 2021 The 13th Haskell Implementors' Workshop is to be held alongside ICFP 2021 this year virtually. It is a forum for people involved in the design and development of Haskell implementations, tools, libraries, and supporting infrastructure, to share their work and discuss future directions and collaborations with others. Talks and/or demos are proposed by submitting an abstract, and selected by a small program committee. There will be no published proceedings. The workshop will be informal and interactive, with open spaces in the timetable and room for ad-hoc discussion, demos, and lightning short talks. Scope and target audience ------------------------- It is important to distinguish the Haskell Implementors' Workshop from the Haskell Symposium which is also co-located with ICFP 2021. The Haskell Symposium is for the publication of Haskell-related research. In contrast, the Haskell Implementors' Workshop will have no proceedings -- although we will aim to make talk videos, slides and presented data available with the consent of the speakers. The Implementors' Workshop is an ideal place to describe a Haskell extension, describe works-in-progress, demo a new Haskell-related tool, or even propose future lines of Haskell development. Members of the wider Haskell community encouraged to attend the workshop -- we need your feedback to keep the Haskell ecosystem thriving. Students working with Haskell are specially encouraged to share their work. The scope covers any of the following topics. There may be some topics that people feel we've missed, so by all means submit a proposal even if it doesn't fit exactly into one of these buckets: * Compilation techniques * Language features and extensions * Type system implementation * Concurrency and parallelism: language design and implementation * Performance, optimisation and benchmarking * Virtual machines and run-time systems * Libraries and tools for development or deployment Talks ----- We invite proposals from potential speakers for talks and demonstrations. We are aiming for 20-minute talks with 5 minutes for questions and changeovers. We want to hear from people writing compilers, tools, or libraries, people with cool ideas for directions in which we should take the platform, proposals for new features to be implemented, and half-baked crazy ideas. Please submit a talk title and abstract of no more than 300 words. Submissions should be made via HotCRP. The website is: https://icfp-hiw21.hotcrp.com/ We will also have lightning talks session. These have been very well received in recent years, and we aim to increase the time available to them. Lightning talks be ~7mins and are scheduled on the day of the workshop. Suggested topics for lightning talks are to present a single idea, a work-in-progress project, a problem to intrigue and perplex Haskell implementors, or simply to ask for feedback and collaborators. Logistics --------- Due to the on-going COVID-19 situation, ICFP (and, consequently, HIW) will be held remotely this year. However, the organizers are still working hard to provide for a great workshop experience. While we are sad that this year will lack the robust hallway track that is often the highlight of HIW, we believe that this remote workshop presents a unique opportunity to include more of the Haskell community in our discussion and explore new modes of communicating with our colleagues. We hope that you will join us in making this HIW as vibrant as any other. Program Committee ----------------- * Dominique Devriese (Vrije Universiteit Brussel) * Daan Leijen (Microsoft Research) * Andres Löh (Well-Typed LLP) * Julie Moronuki (Typeclass Consulting) * John Wiegley (DFINITY) * Ningning Xie (the University of Hong Kong) * Edward Z. Yang (Facebook AI Research) Contact ------- * Ningning Xie <xnning at hku.hk>

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Re: [Haskell-cafe] Tips for debugging seg. faults?
by David Banas 22 Jun '21

22 Jun '21

Thank you, Viktor! Wrt/ `withForeignPtr`, you are suggesting that I use it, not that I avoid it; correct? Wrt/ “pinned memory”, could you give me a little more explanation? Thanks, -db :) > On Jun 20, 2021, at 5:00 AM, haskell-cafe-request(a)haskell.org wrote: > > Thus functions like `withForeignPtr` which try to make sure the the > referenced memory is not released too early. > > Buffer pointers should be to pinned memory, ...

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Re: [Haskell-cafe] Pearl! I just proved theorem about impossibility of monad transformer for parsing with (1) unbiased choice and (2) ambiguity checking before running embedded monadic action (also, I THREAT I will create another parsing lib)
by Askar Safin 22 Jun '21

22 Jun '21

Hi. Thanks for answer! I already wrote arrow parsing lib. I will publish it when I was done. Also, you forgot to add haskell-cafe(a)haskell.org to CC. Понедельник, 21 июня 2021, 21:53 +03:00 от "Olaf Klinke" <olf(a)aatal-apotheke.de>: > Dear Askar, > > your theorem is convincing. While a counterexample is sufficient for a > rigorous proof, I'll try to add some mathematical theory to this. Many > monad transformers are of the form FooT m a = g (m (f a)) where (f,g) > is an adjoint pair of functors. The Kleisli lifting operation (=<<) for > such a composite monad uses the Kleisli lifting of m. For your > application that means that you can not use monadic actions of your > monad transformer without executing the monadic actions of the > transformed monad m. I conjecture that any transformer FooT with the > property that FooT m is a monad provided m is a monad necessarily runs > m-actions. > > A transformer that does not require m to be a monad is the continuation > transformer ContT m r a = (a -> m r) -> m r. However, for this > transformer the lift operation is interdefinable with an operation m (m > r) -> m r so it seems that at least lift will run m-actions. > > As Chris Smith pointed out, this does not rule out that Applicative- > style parsing code may be able to prevent executing the m-actions. > > Olaf > == Askar Safin http://safinaskar.com https://sr.ht/~safinaskar https://github.com/safinaskar

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Is `MonadBaseControl` dead?
by YueCompl 21 Jun '21

21 Jun '21

Greetings! This is also posted at https://www.reddit.com/r/haskell/comments/o4sggi/is_monadbasecontrol_dead/ <https://www.reddit.com/r/haskell/comments/o4sggi/is_monadbasecontrol_dead/> but I'd like to also seek wider help here. (Background issue I'm facing: https://github.com/snapframework/snap-core/issues/309) I think the functionality of [MonadUnliftIO](https://hackage.haskell.org/package/unliftio-core-0.2.0.1/do… is exactly what I want, but unfortunately [Snap](https://hackage.haskell.org/package/snap-core-1.0.4.2/docs/Snap-Core.… appears not eligible for: > the intuition is that a monad must have no monadic state, but may have monadic context. This essentially limits MonadUnliftIO to ReaderT and IdentityT transformers on top of IO. Then I found `Snap` [has a MonadBaseControl instance](https://hackage.haskell.org/package/snap-core-1.0.4.2/docs/src/Sn…, and thought it should work for me. But sadly to find it [losing states](https://github.com/snapframework/snap-core/issues/309). Also I failed to find a user side example of `MonadBaseControl` on Github ([as there're only instance impl. hits](https://github.com/search?l=Haskell&q=org%3Asnapframework+liftBaseWit…) so I have not way to verify whether that's due to my incorrect usage. Any way quoting u/snoyberg : https://github.com/fpco/unliftio/issues/17#issuecomment-363655106 > Continuation-based monads cannot have instances of MonadUnliftIO, the same as MonadBaseControl and MonadMask. Then I'm not sure `Snap`'s `MonadBaseControl` instance shall really work. Also seems there had been debates I'm not aware of with clue at: https://github.com/fpco/unliftio/tree/master/unliftio#monad-control > > The main contention until now is that unlifting in a transformer like > `StateT` is unsafe. This is not universally true: if only one action > is being unlifted, no ambiguity exists. So, for example, `try :: IO a > -> IO (Either e a)` can safely be unlifted in `StateT`, while `finally > :: IO a -> IO b -> IO a` cannot. > > `monad-control` allows us to unlift both styles. In theory, we could > write a variant of `lifted-base` that never does state discards, and > let `try` be more general than `finally`. In other words, this is an > advantage of `monad-control` over `MonadUnliftIO`. We've avoided > providing any such extra typeclass in this package though, for two > reasons: > > * `MonadUnliftIO` is a simple typeclass, easy to explain. We don't > want to complicated matters (`MonadBaseControl` is a notoriously > difficult to understand typeclass). This simplicity > is captured by the laws for `MonadUnliftIO`, which make the > behavior of the run functions close to that of the already familiar > `lift` and `liftIO`. > * Having this kind of split would be confusing in user code, when > suddenly `finally` is not available to us. We would rather encourage > [good practices](https://www.fpcomplete.com/blog/2017/06/readert-design-pattern) > from the beginning. > > Another distinction is that `monad-control` uses the `MonadBase` > style, allowing unlifting to arbitrary base monads. In this package, > we've elected to go with `MonadIO` style. This limits what we can do > (e.g., no unlifting to `STM`), but we went this way because: > > * In practice, we've found that the vast majority of cases are dealing > with `IO` > * The split in the ecosystem between constraints like `MonadBase IO` > and `MonadIO` leads to significant confusion, and `MonadIO` is by > far the more common constraints (with the typeclass existing in > `base`) > So is `MonadBaseControl` dead or alive? Any user side example for it?

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International Conference on Applied Data Science and Intelligence - (ADSI 2021) Prague
by matteo＠confscience.com 21 Jun '21

21 Jun '21

Call for papers ************************************************* International Conference on Applied Data Science and Intelligence - (ADSI 2021) Prague- Czech Republic, October 14-15, 2021 https://confscience.com/adsi/ All papers accepted in ADSI 2021 will be published in Springer CCIS (Communications in Computer and Information Science). CCIS is abstracted/indexed in Scopus, SCImago, EI-Compendex, Mathematical Reviews, DBLP, Google Scholar, and Thomson Reuters Conference Proceedings Citation (Former ISI Proceedings) *************************************************************************** IMPORTANT DATES: - Paper Submission: June 30, 2021 (extended) - Acceptance Notification: July 15, 2021 - Final Manuscript Due: September 1, 2021 *************************************************************************** The ADSI 2021 conference will be held in Conjunction with: International Conference on Recent Theories and Applications in Transportation and Mobility (RTATM 2021) International Conference on Informatics Revolution for Smarter Healthcare (IRSH 2021) *************************************************************************** TOPICS: Authors are invited to submit their original papers to address the topics of the conference, including but not limited to: FUNDAMENTALS AND THEORIES - Theoretical Models - Spatial and temporal multi-models - Multi-dimensional data - Data acquisition and pre-processing - Data inference - Data Classification and Taxonomy - Data Metrics - New approaches for collaboration and competition - Self-organization, self-healing, fault-tolerance approaches - Spatial reasoning - Context awareness - Intelligent mobility - New approaches to supervised and unsupervised learning - New approaches for security, privacy, trust, and ethics in data science - Real-time data analytics - Multi-Agent Systems for data science - Distributed data analytics - Data authenticity - New theories and approaches for Deep learning - New approaches for Business Intelligence - Fuzzy logic - Decision trees - Support vector machines - Evolutionary computation - Statistical methods - Collaborative filtering - Data engineering - Content mining - Indexing schemes - Information retrieval - Metadata use and management INTELLIGENT DATA PROCESSING AND ANALYTICS - Multi-level data processing - Data analytics optimization - Smart data mining - Machine Learning - Deep Learning - Bio-Inspired Computing - Secure data analytics - Privacy in data analytics - Trust in Big Data - Business intelligence - Visualization Analytics - Intelligence as a Service (IaaS) - Data Science as a Service (DSaaS) - Natural Language Processing - Signal Processing - Simulation and Modeling - Data-Intensive Computing SYSTEMS AND INFRASTRUCTURES - Data storage infrastructure - Data warehouses - Data Query and Indexing Technologies - Software Defined Infrastructures - Software Defined Networks (SDN) - Distributed data systems - Smart grid computing - Intelligent data management - Big Data computing - Smart data networking - Internet of Things - Cyber Physical Systems - Blockchain - Fog and Edge intelligence - Parallel Computing systems - Open Source systems for data science - Embedded intelligence - Embedded data science - In-Memory computing - Intelligent drones - Internet of Drones - Real-time data acquisition systems APPLICATIONS - Intelligent Hazard management - Intelligent data science in healthcare - Intelligent data science in farming - Intelligent data science in Oil and Gas - Smart logistics - Intelligent data science in transportation - Intelligent data science in surveillance - Xtech (Fintech, Agritech, etc.) - Intelligent drones - Digital transformation - Bioinformatics - Marketing - Social Science - E-learning and E-services *************************************************************************** OUTSTANDING PAPERS: Based on the peer review scores as well as the presentations at the conference, the authors of outstanding papers will be invited to extend their works for a potential publication in journals special issues with high impact factors. *************************************************************************** PAPER SUBMISSION: Papers must be submitted electronically as PDF files via easychair (https://easychair.org/conferences/?conf=adsi2021) All papers will be peer reviewed. Length of Full papers: 12-15 pages long (written in the LNCS/CCIS one-column page format, 400 words per page) Length of Short papers: less than 12 pages For more information, please refer to the conference website: https://confscience.com/adsi/ *************************************************************************** CONTACT For more information, please send an email to info-adsi(a)confscience.com

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International Conference on Recent Theories and Applications in Transportation and Mobility - (RTATM 2021) Prague
by matteo＠confscience.com 21 Jun '21

21 Jun '21

Call for papers ************************************************* International Conference on Recent Theories and Applications in Transportation and Mobility - (RTATM 2021) Prague - Czech Republic, October 14-15, 2021 https://confscience.com/rtatm/ All papers accepted in RTATM 2021 will be published in Springer CCIS (Communications in Computer and Information Science). CCIS is abstracted/indexed in Scopus, SCImago, EI-Compendex, Mathematical Reviews, DBLP, Google Scholar, and Thomson Reuters Conference Proceedings Citation (Former ISI Proceedings) *************************************************************************** IMPORTANT DATES: - Paper Submission: June 30, 2021 (extended) - Acceptance Notification: July 15, 2021 - Final Manuscript Due: September 1, 2021 *************************************************************************** The RTATM 2021 conference will be held in Conjunction with: International Conference on Applied Data Science and Intelligence (ADSI 2021) International Conference on Informatics Revolution for Smarter Healthcare (IRSH 2021) *************************************************************************** TOPICS: Authors are invited to submit their original papers to address the topics of the conference, including but not limited to: FUNDAMENTALS AND THEORIES - Modelling and Simulation Algorithms - Vehicular Wireless Medium Access Control - V2X communications - Routings and Protocols for Connected Vehicles - Mobility Models and Architectures - Distribution Strategies - Traffic Incident Management Systems - Bio-Inspired Approaches - Optimization and Collaboration - Automatic Control in Vehicular Networks - Energy-aware Connected Mobility - Programming Languages - Sustainable Transportation - Multimodal Transportation Networks and Systems - Systemsb Integration - Driver Behavior Models and Simulation - Human Factors and Travel Behaviour - Green Mobility - Regulations and Bylaws for Intelligent - Transportation and Mobility SMART TRANSPORTATION AND LOGISTICS - Mobility Management - Connected Vehicles - VANETs - Predictive Logistics - Spatio-Temporal Event Tracking - Decision Support Systems - Emergency Management - Logistics and E-Commerce - Supply Chain Design and Execution - Supply Chain Management - Advanced Planning Systems - Fleet Management - Multi-Agent Systems - Machine Learning for Smart Logistics - Intelligent Infrastructures - Real-time Analysis of Comprehensive Supply Chain Data - Smart Synchronization of Logistics Processes - New Approaches for Cost Transparency - Big Data for Smart Logistics - Logistics 4.0 - Mobile Networks - Next-Generation Smart Logistics - Performance Management Approaches - Tests and Deployment - Software Defined Networks - Smart Freight Management - Smart Shipment Management - Smart Warehousing - Smart Inventory management DATA AND SERVICES - Real-Time transportation Data Acquisition - Event Detection and Monitoring - Data Warehouses for connected mobility - Data mining and Data analytics - Data Worthiness in Connected Vehicles - Data Trustworthiness for effective transportation and mobility - Road Traffic Data Analytics - Structured and Unstructured Data for Connected Mobility - Volunteered Geographic Information (VGI) - Data Representation for Connected Mobility - Transportation Data Mining - Transportation and mobility Data Visualization - Cognitive and Context-aware Intelligence - Transportation Decision Support Systems - Mobility as a Service (MaaS) - Intelligent Transportation Services - Smart Mobility Services - Big Data and Vehicle Analytics - Massive Data Management - Collective and connected Intelligence - Next Generation Services - Driver Behaviour Analysis - Geo-Spatial Services - Service-Oriented Architecture (SOA) - Web and Mobile Services SAFETY, SECURITY, AND HAZARD MANAGEMENT - Security Issues in Vehicular Communications - Safety Applications of Connected Vehicles - Weather-related Safety solutions - V2V, V2I and I2V Road Safety Applications - Connected Mobility for Hazard Management - Risk Management - Road Traffic Crashes Analytics - Traffic Jam Prediction - Resource Allocation for Hazard Management - Trust and Privacy Issues in Logistics - Management of Exceptional Events - New approaches to Networking Security for Transportation Applications - Failure modes, human factors, software safety - Automated Failure Analysis - Performance and Human Error Analysis - Design and Reliability of Control Systems - Dispersion Modelling Software - Quantification of Risk *************************************************************************** OUTSTANDING PAPERS: Based on the peer review scores as well as the presentations at the conference, the authors of outstanding papers will be invited to extend their works for a potential publication in journals special issues with high impact factors. *************************************************************************** PAPER SUBMISSION: Papers must be submitted electronically as PDF files via easychair (https://easychair.org/conferences/?conf=rtatm2021) All papers will be peer reviewed. Length of Full papers: 12-15 pages long (written in the LNCS/CCIS one-column page format, 400 words per page) Length of Short papers: less than 12 pages For more information, please refer to the conference website: https://confscience.com/rtatm/ *************************************************************************** CONTACT For more information, please send an email to info-rtatm(a)confscience.com

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Fwd: Haskell colour package repository
by Harendra Kumar 20 Jun '21

20 Jun '21

Does anyone know who maintains the "colour" package or where the repository is hosted? I tried to contact Russell O'Connor but did not get a response. -harendra ---------- Forwarded message --------- From: Harendra Kumar <harendra.kumar(a)gmail.com> Date: Mon, 17 May 2021 at 05:38 Subject: Haskell colour package repository To: <roconnor(a)theorem.ca> Hi, I was building something that depends on https://hackage.haskell.org/package/colour package using GHC-9.3, and it's failing to build. I was wondering if it is possible to add a URL to the package repository in the cabal file of the package so that I can clone/fix/send a PR? Or maybe a URL for reporting issues/bugs? Thanks, Harendra

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Tips for debugging seg. faults?
by David Banas 19 Jun '21

19 Jun '21

Does anyone have any helpful tips for debugging seg. faults in a Haskell program that calls out to a C library, via the FFI?

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