February 2021 - Haskell-Cafe

Haskell exercises for beginners
by Olaf Klinke 06 Feb '21

06 Feb '21

> Hello Haskell Café, > > I have been working on a website aimed at teaching programming and Computer > Science through quick examples. It is called "Computer Science by Example > <https://cscx.org/>;": https://cscx.org/ > > The exercises start very simple (e.g. read two numbers and print their sum > <https://cscx.org/add>;) then increase in difficulty and complexity > gradually (e.g. solving the change-making problem <https://cscx.org/cash>;). > The website has an "online judge" functionality where students can submit > their solutions which are tested and graded automatically without human > intervention. It currently supports solutions in *Haskell* and > additionally: Python, C, C++, C#, Java, JavaScript, Lua and Ruby. > > The exercises are useful not only to first time programmers, but also to > experienced programmers trying to learn a new language such as Haskell. > > Check it out at cscx.org. The exercises are freely available for anyone to > try. > > Best Regards, > Rudy Dear Rudy, thanks for sharing all these excercises. Automated grading has many advantages. The kind of automated grading cscx uses lets the program use stdin and stdout. However, for Haskell (and all other programming languages too) this means that students are, from the very beginning, forced to write parsers for the data the grading system gives on stdin. This means that either * You limit input data to stuff with built-in parsers (which you don't) * You teach proper parsing early, which is non-trivial, or * You permit the students develop an ad-hoc and potentially messy style of coping with unstructured input. In all the excercises I looked at, the grading specification does not say what the program should do with invalid input. Therefore messy ad- hoc parsing is what you should expect to see in, and in some cases comprise the largest part of, submitted solutions. Others may disagree whether this is to be prevented or not. I have limited experience in teaching. In some other CS courses the excercises give a program fragment which is to be completed by the student. In Haskell you could use property- based testing [1] like QuickCheck or doctests to do the heavy lifting for you, while at the same time presenting the students with an infinity of test cases. Another way might be to provide a random generator of structured test data, and the student's task is to write a program that echoes the random data together with the computed result. That way, you could still use the stdout-based automated grading. Example of QuickCheck-based grading: module Triple1 where -- Your task: Complete this function -- so that for example -- -- >>> triple 2 -- 6 -- >>> triple 123 -- 369 triple :: Integer -> Integer triple = undefined -- Automated grading appends the following and runs -- quickCheck prop_triple prop_triple :: Integer -> Bool prop_triple = triple n == 3*n Example of Random-based grading: module Triple1 where -- Your task: complete this function -- so that for example -- -- >>> pure 2 >>= triple -- 2 -- 6 triple :: Integer -> IO () triple n = do print n undefined -- Automated grading compiles -- main = (yourIntegerGenerator :: IO Integer) >>= triple -- and executes repeatedly. Kind regards Olaf [1] https://www.cs.tufts.edu/~nr/cs257/archive/john-hughes/automatic-grading.pdf

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International Conference on Applied Data Science and Intelligence - (ADSI 2021) Prague
by matteo＠confscience.com 06 Feb '21

06 Feb '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/ Submission deadline: April 1, 2021 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: April 1, 2021 - Acceptance Notification: July 1, 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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Haskell exercises for beginners
by Rudy Matela 05 Feb '21

05 Feb '21

Hello Haskell Café, I have been working on a website aimed at teaching programming and Computer Science through quick examples. It is called "Computer Science by Example <https://cscx.org/>": https://cscx.org/ The exercises start very simple (e.g. read two numbers and print their sum <https://cscx.org/add>) then increase in difficulty and complexity gradually (e.g. solving the change-making problem <https://cscx.org/cash>). The website has an "online judge" functionality where students can submit their solutions which are tested and graded automatically without human intervention. It currently supports solutions in *Haskell* and additionally: Python, C, C++, C#, Java, JavaScript, Lua and Ruby. The exercises are useful not only to first time programmers, but also to experienced programmers trying to learn a new language such as Haskell. Check it out at cscx.org. The exercises are freely available for anyone to try. Best Regards, Rudy

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International Conference on Recent Theories and Applications in Transportation and Mobility - (RTATM 2021) Prague
by matteo＠confscience.com 04 Feb '21

04 Feb '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/ Submission deadline: April 1, 2021 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: April 1, 2021 - Acceptance Notification: July 1, 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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TH: quoting name and value
by Sylvain Henry 02 Feb '21

02 Feb '21

Hi, I have the following kind of template haskell code: module Foo where foo :: String -> Name -> Q [Dec] foo str name = return [] module Bar where bar :: String bar = "whatever" module FooBar where import Foo import Bar foo bar 'bar It works great as in `foo` I can use both bar's Name and bar's value computed at compile time. But it's unsafe for my purpose because a user could call: `foo "fakeBarValue" 'bar` So the question is: is there a way to write `foo` so that it can only be used safely? If not, I guess it could be possible to add a new kind of quote to TH, something like: data Named a = Named Name a -- constructor not exported so that Named values can't be forged by users. [namedValue||bar||] :: Named String -- new quote What do you think? Thanks, Sylvain

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Call for Papers: PACMPL issue ICFP 2021
by Sam Tobin-Hochstadt 02 Feb '21

02 Feb '21

PACMPL Volume 5, Issue ICFP 2021 Call for Papers Accepted papers to be invited for presentation at The 26th ACM SIGPLAN International Conference on Functional Programming To Be Held Virtualy http://icfp21.sigplan.org/ ### Important dates Submissions due: 2 March 2021 (Tuesday) Anywhere on Earth https://icfp21.hotcrp.com Author response: 20 April (Tuesday) - 23 April (Friday) 17:00 UTC Notification: 7 May (Friday) Final copy due: 30 June (Wednesday) Conference: 22 August (Sunday) - 27 August (Friday) ### About PACMPL Proceedings of the ACM on Programming Languages (PACMPL <https://pacmpl.acm.org/>) is a Gold Open Access journal publishing research on all aspects of programming languages, from design to implementation and from mathematical formalisms to empirical studies. Each issue of the journal is devoted to a particular subject area within programming languages and will be announced through publicized Calls for Papers, like this one. ### Scope [PACMPL](https://pacmpl.acm.org/) issue ICFP 2021 seeks original papers on the art and science of functional programming. Submissions are invited on all topics from principles to practice, from foundations to features, and from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects, concurrency, or parallelism. Topics of interest include (but are not limited to): * Language Design: concurrency, parallelism, and distribution; modules; components and composition; metaprogramming; macros; pattern matching; type systems; type inference; dependent types; session types; gradual typing; refinement types; interoperability; domain-specific languages; imperative programming; object-oriented programming; logic programming; probabilistic programming; reactive programming; generic programming; bidirectional programming. * Implementation: abstract machines; virtual machines; interpretation; compilation; compile-time and run-time optimization; garbage collection and memory management; runtime systems; multi-threading; exploiting parallel hardware; interfaces to foreign functions, services, components, or low-level machine resources. * Software-Development Techniques: algorithms and data structures; design patterns; specification; verification; validation; proof assistants; debugging; testing; tracing; profiling; build systems; program synthesis. * Foundations: formal semantics; lambda calculus; program equivalence; rewriting; type theory; logic; category theory; monads; continuations; control; state; effects; names and binding; program verification. * Analysis and Transformation: control flow; data flow; abstract interpretation; partial evaluation; program calculation. * Applications: symbolic computing; formal-methods tools; artificial intelligence; systems programming; distributed systems and web programming; hardware design; databases; XML processing; scientific and numerical computing; graphical user interfaces; graphics and multimedia; GPU programming; scripting; system administration; security. * Education: teaching introductory programming; parallel programming; mathematical proof; algebra. Submissions will be evaluated according to their relevance, correctness, significance, originality, and clarity. Each submission should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. The technical content should be accessible to a broad audience. PACMPL issue ICFP 2021 also welcomes submissions in two separate categories — Functional Pearls and Experience Reports — that must be marked as such when submitted and that need not report original research results. Detailed guidelines on both categories are given at the end of this call. Please contact the associate editor if you have questions or are concerned about the appropriateness of a topic. ### Preparation of submissions **Deadline**: The deadline for submissions is **Tuesday, March 2, 2021**, Anywhere on Earth (<https://www.timeanddate.com/time/zones/aoe>). This deadline will be strictly enforced. **Formatting**: Submissions must be in PDF format, printable in black and white on US Letter sized paper, and interpretable by common PDF tools. All submissions must adhere to the "ACM Small" template that is available (in both LaTeX and Word formats) from <https://www.acm.org/publications/authors/submissions>. There is a limit of **25 pages for a full paper or Functional Pearl** and **12 pages for an Experience Report**; in either case, the bibliography will not be counted against these limits. Submissions that exceed the page limits or, for other reasons, do not meet the requirements for formatting, will be summarily rejected. Supplementary material can and should be **separately** submitted (see below). See also PACMPL's Information and Guidelines for Authors at <https://pacmpl.acm.org/authors.cfm>. **Submission**: Submissions will be accepted at <https://icfp21.hotcrp.com/> Improved versions of a paper may be submitted at any point before the submission deadline using the same web interface. **Author Response Period**: Authors will have a 72-hour period, starting at 17:00 UTC on **Tuesday, April 20, 2021**, to read reviews and respond to them. **Supplementary Material**: Authors have the option to attach supplementary material to a submission, on the understanding that reviewers may choose not to look at it. This supplementary material should **not** be submitted as part of the main document; instead, it should be uploaded as a **separate** PDF document or tarball. Supplementary material should be uploaded **at submission time**, not by providing a URL in the paper that points to an external repository. Authors are free to upload both anonymized and non-anonymized supplementary material. Anonymized supplementary material will be visible to reviewers immediately; non-anonymized supplementary material will be revealed to reviewers only after they have submitted their review of the paper and learned the identity of the author(s). **Authorship Policies**: All submissions are expected to comply with the ACM Policies for Authorship that are detailed at <https://www.acm.org/publications/authors/information-for-authors>. **Republication Policies**: Each submission must adhere to SIGPLAN's republication policy, as explained on the web at <http://www.sigplan.org/Resources/Policies/Republication>. ### Review Process This section outlines the two-stage process with lightweight double-blind reviewing that will be used to select papers for PACMPL issue ICFP 2021. We anticipate that there will be a need to clarify and expand on this process, and we will maintain a list of frequently asked questions and answers on the PACMPL issue website to address common concerns. **PACMPL issue ICFP 2021 will employ a two-stage review process.** The first stage in the review process will assess submitted papers using the criteria stated above and will allow for feedback and input on initial reviews through the author response period mentioned previously. As a result of the review process, a set of papers will be conditionally accepted and all other papers will be rejected. Authors will be notified of these decisions on **May 7, 2021**. Authors of conditionally accepted papers will be provided with committee reviews along with a set of mandatory revisions. After four weeks (June 4, 2021), the authors will provide a second submission. The second and final reviewing phase assesses whether the mandatory revisions have been adequately addressed by the authors and thereby determines the final accept/reject status of the paper. The intent and expectation is that the mandatory revisions can be addressed within four weeks and hence that conditionally accepted papers will in general be accepted in the second phase. The second submission should clearly identify how the mandatory revisions were addressed. To that end, the second submission must be accompanied by a cover letter mapping each mandatory revision request to specific parts of the paper. The cover letter will facilitate a quick second review, allowing for confirmation of final acceptance within two weeks. Conversely, the absence of a cover letter will be grounds for the paper’s rejection. **PACMPL issue ICFP 2021 will employ a lightweight double-blind reviewing process.** To facilitate this, submitted papers must adhere to two rules: 1. **author names and institutions must be omitted**, and 2. **references to authors' own related work should be in the third person** (e.g., not "We build on our previous work ..." but rather "We build on the work of ..."). The purpose of this process is to help the reviewers come to an initial judgement about the paper without bias, not to make it impossible for them to discover the authors if they were to try. Nothing should be done in the name of anonymity that weakens the submission or makes the job of reviewing the paper more difficult (e.g., important background references should not be omitted or anonymized). In addition, authors should feel free to disseminate their ideas or draft versions of their paper as they normally would. For instance, authors may post drafts of their papers on the web or give talks on their research ideas. ### Information for Authors of Accepted Papers * As a condition of acceptance, final versions of all papers must adhere to the new ACM Small format. The page limit for the final versions of papers will be increased by two pages to help authors respond to reviewer comments and mandatory revisions: **27 pages plus bibliography for a regular paper or Functional Pearl, 14 pages plus bibliography for an Experience Report**. * Authors of accepted submissions will be required to agree to one of the three ACM licensing options: open access on payment of a fee (**recommended**, and SIGPLAN can cover the cost as described next); copyright transfer to ACM; or retaining copyright but granting ACM exclusive publication rights. Further information about ACM author rights is available from <http://authors.acm.org>. * PACMPL is a Gold Open Access journal, and authors are encouraged to publish their work under a CC-BY license. Gold Open Access guarantees permanent free online access to the definitive version in the ACM Digital Library, and the recommended CC-BY option also allows anyone to copy and distribute the work with attribution. Gold Open Access has been made possible by generous funding through ACM SIGPLAN, which will cover all open access costs in the event authors cannot. Authors who can cover the costs may do so by paying an Article Processing Charge (APC). PACMPL, SIGPLAN, and ACM Headquarters are committed to exploring routes to making Gold Open Access publication both affordable and sustainable. * ACM offers authors a range of copyright options, one of which is Creative Commons CC-BY publication; this is the option recommended by the PACMPL editorial board. A reasoned argument in favour of this option can be found in the article [Why CC-BY?](https://oaspa.org/why-cc-by/) published by OASPA, the Open Access Scholarly Publishers Association. * ACM Author-Izer is a unique service that enables ACM authors to generate and post links on either their home page or institutional repository for visitors to download the definitive version of their articles from the ACM Digital Library at no charge. Downloads through Author-Izer links are captured in official ACM statistics, improving the accuracy of usage and impact measurements. Consistently linking to the definitive version of an ACM article should reduce user confusion over article versioning. After an article has been published and assigned to the appropriate ACM Author Profile pages, authors should visit <http://www.acm.org/publications/acm-author-izer-service> to learn how to create links for free downloads from the ACM DL. * The official publication date is the date the papers are made available in the ACM Digital Library. This date may be up to *two weeks prior* to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work. * Authors of each accepted submission are invited to attend and be available for the presentation of that paper at the conference. The schedule for presentations will be determined and shared with authors after the full program has been selected. ### Artifact Evaluation Authors of papers that are conditionally accepted in the first phase of the review process will be encouraged (but not required) to submit supporting materials for Artifact Evaluation. These items will then be reviewed by an Artifact Evaluation Committee, separate from the paper Review Committee, whose task is to assess how the artifacts support the work described in the associated paper. Papers that go through the Artifact Evaluation process successfully will receive a seal of approval printed on the papers themselves. Authors of accepted papers will be encouraged to make the supporting materials publicly available upon publication of the papers, for example, by including them as "source materials" in the ACM Digital Library. An additional seal will mark papers whose artifacts are made available, as outlined in the ACM guidelines for artifact badging. Participation in Artifact Evaluation is voluntary and will not influence the final decision regarding paper acceptance. ### Special categories of papers In addition to research papers, PACMPL issue ICFP solicits two kinds of papers that do not require original research contributions: Functional Pearls, which are full papers, and Experience Reports, which are limited to half the length of a full paper. Authors submitting such papers should consider the following guidelines. #### Functional Pearls A Functional Pearl is an elegant essay about something related to functional programming. Examples include, but are not limited to: * a new and thought-provoking way of looking at an old idea * an instructive example of program calculation or proof * a nifty presentation of an old or new data structure * an interesting application of functional programming techniques * a novel use or exposition of functional programming in the classroom While pearls often demonstrate an idea through the development of a short program, there is no requirement or expectation that they do so. Thus, they encompass the notions of theoretical and educational pearls. Functional Pearls are valued as highly and judged as rigorously as ordinary papers, but using somewhat different criteria. In particular, a pearl is not required to report original research, but, it should be concise, instructive, and entertaining. A pearl is likely to be rejected if its readers get bored, if the material gets too complicated, if too much specialized knowledge is needed, or if the writing is inelegant. The key to writing a good pearl is polishing. A submission that is intended to be treated as a pearl must be marked as such on the submission web page, and should contain the words "Functional Pearl" somewhere in its title or subtitle. These steps will alert reviewers to use the appropriate evaluation criteria. Pearls will be combined with ordinary papers, however, for the purpose of computing the conference's acceptance rate. #### Experience Reports The purpose of an Experience Report is to help create a body of published, refereed, citable evidence that functional programming really works -- or to describe what obstacles prevent it from working. Possible topics for an Experience Report include, but are not limited to: * insights gained from real-world projects using functional programming * comparison of functional programming with conventional programming in the context of an industrial project or a university curriculum * project-management, business, or legal issues encountered when using functional programming in a real-world project * curricular issues encountered when using functional programming in education * real-world constraints that created special challenges for an implementation of a functional language or for functional programming in general An Experience Report is distinguished from a normal PACMPL issue ICFP paper by its title, by its length, and by the criteria used to evaluate it. * Both in the papers and in any citations, the title of each accepted Experience Report must end with the words "(Experience Report)" in parentheses. The acceptance rate for Experience Reports will be computed and reported separately from the rate for ordinary papers. * Experience Report submissions can be at most 12 pages long, excluding bibliography. * Each Experience Report accepted to the PACMPL issue will be presented at the conference, but depending on the number of Experience Reports and regular papers accepted, authors of Experience reports may be asked to give shorter talks. * Because the purpose of Experience Reports is to enable our community to accumulate a body of evidence about the efficacy of functional programming, an acceptable Experience Report need not add to the body of knowledge of the functional-programming community by presenting novel results or conclusions. It is sufficient if the Report states a clear thesis and provides supporting evidence. The thesis must be relevant to the PACMPL issue, but it need not be novel. The review committee will accept or reject Experience Reports based on whether they judge the evidence to be convincing. Anecdotal evidence will be acceptable provided it is well argued and the author explains what efforts were made to gather as much evidence as possible. Typically, more convincing evidence is obtained from papers which show how functional programming was used than from papers which only say that functional programming was used. The most convincing evidence often includes comparisons of situations before and after the introduction or discontinuation of functional programming. Evidence drawn from a single person's experience may be sufficient, but more weight will be given to evidence drawn from the experience of groups of people. An Experience Report should be short and to the point: it should make a claim about how well functional programming worked on a particular project and why, and produce evidence to substantiate this claim. If functional programming worked in this case in the same ways it has worked for others, the paper need only summarize the results; the main part of the paper should discuss how well it worked and in what context. Most readers will not want to know all the details of the project and its implementation, but the paper should characterize the project and its context well enough so that readers can judge to what degree this experience is relevant to their own projects. The paper should take care to highlight any unusual aspects of the project. Specifics about the project are more valuable than generalities about functional programming; for example, it is more valuable to say that the team delivered its software a month ahead of schedule than it is to say that functional programming made the team more productive. If the paper not only describes experience but also presents new technical results, or if the experience refutes cherished beliefs of the functional-programming community, it may be better to submit it as a full paper, which will be judged by the usual criteria of novelty, originality, and relevance. The associate editor will be happy to advise on any concerns about which category to submit to. ### ICFP Organizers General Chair: Sukyoung Ryu (KAIST, South Korea) Accessibility Co-Chairs: Lindsey Kuper (UC Santa Cruz, USA), Kathrin Stark (Princeton University, USA) Artifact Evaluation Co-Chairs: Gabriel Scherer (INRIA Saclay, France), Brent Yorgey (Hendrix College, USA) Industrial Relations Co-Chairs: Alan Jeffrey (Roblox, USA), Simon Marlow (Facebook, England) Programming Contest Co-Organisers: Alex Lang, Jasper Van der Jeugt (Fugue, Switzerland) Publicity and Web Chair: Sam Tobin-Hochstadt (Indiana University, USA) Student Research Competition Chair: Anders Miltner (University of Texas, USA) Student Volunteer Co-Chairs: Lily Bryant (University of British Columbia, Canada), Jaemin Hong (KAIST, South Korea), Hanneli Tavante (McGill University, Canada) Video Co-Chairs: Leif Andersen (Northeastern University, USA), Benjamin Chung (Northeastern University, USA) Workshops Co-Chairs: Leonidas Lampropoulos (University of Maryland, USA), Zoe Paraskevopoulou (Princeton University, USA) ### PACMPL Volume 5, Issue ICFP 2021 Associate Editor: Ronald Garcia, (University of British Columbia, Canada) Review Committee: Zena Ariola (University of Oregon, USA) Stephanie Balzer (Carnegie Mellon University, USA) Matteo Cimini (UMass Lowell, USA) Youyou Cong (Tokyo Institute of Technology, Japan) Harley Eades (University of Augusta, USA) Andrew Gordon (Microsoft Research & University of Edinburgh, United Kingdom) Benjamin Greenman (Brown University, USA) Arjun Guha (Northeastern University, USA) Jurriaan Hage (Utrecht, The Netherlands) Favonia (University of Minnesota, USA) Suresh Jagannathan (Purdue University, USA) Patricia Johann (Appalachian State University, USA) Ralf Jung (Max Planck Institute, Germany) Ekaterina Komendantskaya (Heriot-Watt, Scotland) Leonidas Lampropoulos (University of Maryland, USA) Kazutaka Matsuda (Tohoku University, Japan) Akimasa Morihata (Univeristy of Tokyo, Japan) Stefan Muller (Illinois Institute of Technology, USA) Max New (Wesleyan University, USA) Rishiyur Nikhil (Bluespec , USA) Cyrus Omar (University of Michigan, USA) Brigitte Pientka (McGill University, Canada) Norman Ramsey (Tufts University, USA) Christine Rizkallah (University of New South Wales, Australia) Taro Sekiyama (National Institute for Informatics, Japan) Eijiro Sumii (Tohoku University, Japan) Amin Timany (Aarhus University, Denmark) Mitchell Wand (Northeastern University, USA) Steve Zdancewic (University of Pennsylvania, USA)

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PhD position at IMDEA Software Institute
by Niki Vazou 02 Feb '21

02 Feb '21

Hey Haskellers, Applications are invited for a PhD position at the IMDEA Software Institute, Madrid, Spain. The selected candidate will work under my supervision on the theory and practise of refinement types. Application deadline is March 15. More information are available here: https://software.imdea.org/open_positions/2021-02-phd-refinements.html Best, Niki Vazou

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Project builds with stack, not with cabal. How to diagnose?
by Han Joosten 01 Feb '21

01 Feb '21

Dear Café, I have been building my project for quite some time now using Stack. That works fine. However, I also want to make sure cabal users can build it from source. Recently I have been trying to set this up using github actions. I use a matrix to build both with stack and with cabal. I use the same version of ghc. A recent build can be seen here: https://github.com/AmpersandTarski/Ampersand/runs/1756887612 I guess that the error is due to the fact that the used packages to build are somehow different between the stack build and the cabal build. Is there some way to find out what those differences are? Any help would be appreciated! Thanks Han Joosten

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