- Haskell-Cafe - Haskell.org

Records, type-changing update, type inference
by Roman 21 Dec '19

21 Dec '19

I wrote a post about the records problem, in particular about type-changing update and how to get it without sacrificing type inference: https://github.com/effectfully/sketches/tree/master/has-lens-done-right The ideas are rather raw, but look promising to me. Any comments would be appreciated.

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PhD and Postdoc positions at IMDEA
by Niki Vazou 21 Dec '19

21 Dec '19

Dear all, IMDEA Software Institute has open PhD and Postdoc positions. The selected candidate will work on liquid relational types and the application deadline is February 1st: https://software.imdea.org/open_positions.html Feel free to contact me for more information. Best, Niki

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Third call for draft papers for TFPIE 2020 (Trends in Functional Programming in Education)
by Jurriaan Hage 20 Dec '19

20 Dec '19

Hello, Please, find below the third call for draft papers for TFPIE 2020. Please forward these to anyone you think may be interested. Apologies for any duplicates you may receive. best regards, Jurriaan Hage Chair of TFPIE 2020 ======================================================================== TFPIE 2020 Call for papers http://www.staff.science.uu.nl/~hage0101/tfpie2020/index.html February 12th 2020, Krakow, Poland (co-located with TFP 2020 and Lambda Days) *NEW* Invited Speaker We are happy to announce the invited speaker for TFPIE 2020, Thorsten Altenkirch, who also speaks at Lambda Days. At TFPIE 2020 he shall be talking about his new book, Conceptual Programming With Python. *NEW* Registration This year TFPIE takes place outside of the Lambda Days/TFP organisation, although it takes place near their location. This means you do need to register separately for TFPIE; it also means you can register for TFPIE without registering for TFP/LambdaDays, and vice versa. Registration is mandatory for at least one author of every paper that is presented at the workshop. Only papers that have been presented at TFPIE may be submitted to the post-reviewing process. Registration is 25 euro per person. TFPIE 2020 welcomes submissions describing techniques used in the classroom, tools used in and/or developed for the classroom and any creative use of functional programming (FP) to aid education in or outside Computer Science. Topics of interest include, but are not limited to: FP and beginning CS students FP and Computational Thinking FP and Artificial Intelligence FP in Robotics FP and Music Advanced FP for undergraduates FP in graduate education Engaging students in research using FP FP in Programming Languages FP in the high school curriculum FP as a stepping stone to other CS topics FP and Philosophy The pedagogy of teaching FP FP and e-learning: MOOCs, automated assessment etc. Best Lectures - more details below In addition to papers, we are requesting best lecture presentations. What's your best lecture topic in an FP related course? Do you have a fun way to present FP concepts to novices or perhaps an especially interesting presentation of a difficult topic? In either case, please consider sharing it. Best lecture topics will be selected for presentation based on a short abstract describing the lecture and its interest to TFPIE attendees. The length of the presentation should be comparable to that of a paper. On top of the lecture itself, the presentation can also provide commentary on the lecture. Submissions Potential presenters are invited to submit an extended abstract (4-6 pages) or a draft paper (up to 20 pages) in EPTCS style. The authors of accepted presentations will have their preprints and their slides made available on the workshop's website. Papers and abstracts can be submitted via easychair at the following link: https://easychair.org/conferences/?conf=tfpie2020 . After the workshop, presenters will be invited to submit (a revised version of) their article for review. The PC will select the best articles that will be published in the Electronic Proceedings in Theoretical Computer Science (EPTCS). Articles rejected for presentation and extended abstracts will not be formally reviewed by the PC. Dates Submission deadline: January 14th 2020, Anywhere on Earth. Notification: January 17th 2020 TFPIE Registration Deadline: January 20th 2020 Workshop: February 12th 2020 Submission for formal review: April 19th 2020, Anywhere on Earth. Notification of full article: June 6th 2020 Camera ready: July 1st 2020 Program Committee Olaf Chitil - University of Kent Youyou Cong - Tokyo Institute of Technology Marko van Eekelen - Open University of the Netherlands and Radboud University Nijmegen Jurriaan Hage (Chair) - Utrecht University Marco T. Morazan - Seton Hall University, USA Sharon Tuttle - Humboldt State University, USA Janis Voigtlaender - University of Duisburg-Essen Viktoria Zsok - Eotvos Lorand University Note: information on TFP is available at http://www.cse.chalmers.se/~rjmh/tfp/

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[ANN] Venzone, an ASCII adventure/platformer
by Francesco Ariis 20 Dec '19

20 Dec '19

Hello -cafe, I am pleased to announce the release of `venzone`, an ASCII platform/adventure game. See it in action here: http://www.ariis.it/static/articles/venzone/venzone-cast.gif Get it (binaries or source) in the game page [1] or check Discourse [2] for a more details on the release. Happy festivities everyone! -F [1] http://www.ariis.it/static/articles/venzone/page.html [2] https://discourse.haskell.org/t/venzone-an-ascii-adventure-platformer-writt…

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Haskell 2010 report nit?
by Viktor Dukhovni 18 Dec '19

18 Dec '19

Not sure where to post about this, and it has likely been noted elsewhere already, but reading through the report I see in Section 3.17.2 > • Consider the following declarations: > > newtype N = N Bool > data D = D !Bool > > These examples illustrate the difference in pattern matching between types defined by data and newtype: > > (\ (N True) -> True) ⊥ ⇒ ⊥ > (\ (D True) -> True) ⊥ ⇒ ⊥ > (\ ~(D True) -> True) ⊥ ⇒ True > > Additional examples may be found in Section 4.2.3. But unlike the examples in 4.2.3, which do show differences between "newtype" and "data", the above does not seem to show any actual difference. For that the pattern after the constructor would I believe have to be irrefutable, which "True" is not. Thus, e.g. the below (which duplicates 4.2.3) would do the job: (\ (N _) -> True) ⊥ ⇒ True (\ (D _) -> True) ⊥ ⇒ ⊥ Perhaps I misunderstood something, but if not, and this has not been noted before, it may be worth fixing in the next revision. -- Viktor.

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Practical Aspects of Declarative Languages (PADL 2020) Call for Participation
by Ekaterina Komendantskaya 18 Dec '19

18 Dec '19

PADL 2020 Final Call for Participation: Please see many exciting talks and events at PADL 2020: The 22nd Symposium on Practical Aspects of Declarative Languages https://popl20.sigplan.org/home/PADL-2020 (Early registration by 12/18) Invited Talks Nikolaj Bjørner, Microsoft Research Logical Engines for Cloud Configurations Adnan Darwiche, UCLA Symbolic Reasoning About Machine Learning Systems Invited Experience and Direction Session Invited Talks Molham Aref, Relational AI Relational Artificial Intelligence Mayur Naik, University of Pennsylvania Learning Interpretable Rules from Structured Data Grant Passmore, Imandra Inc. and Cambridge University An Introduction to the Imandra Automated Reasoning System Philip Wadler, University of Edinburgh We Are All Poor Schmucks: On the Value of Gradual Types [image: Nikolaj Bjørner][image: Adnan Darwiche][image: Molham Aref][image: Grant Passmore][image: Mayur Naik][image: Phil Wadler] Complete Program https://popl20.sigplan.org/home/PADL-2020#program This includes also presentations of 10 full papers and 4 short papers; four discussion panels: (1) Programming with Logic for the Masses, (2) Memory and Real-Time Programming in Practice, (3) Reasoning for Machine Learning at Large, and (4) Experience and Direction; and a competitive programming experience session. Registration https://regmaster4.com/2020conf/POPL20/register.php Early rate closes on December 18th

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[ANNOUNCE] lzlib - lzma compression/decompression for Haskell
by Vanessa McHale 17 Dec '19

17 Dec '19

Hi all, I have written http://hackage.haskell.org/package/lzlib, a high-level interface to the lzlib library. Cheers, Vanessa McHale

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10 PhD studentships in Nottingham
by Graham Hutton 17 Dec '19

17 Dec '19

Dear all, The School of Computer Science at the University of Nottingham is seeking applications for 10 fully-funded international PhD studentships: https://tinyurl.com/10-phds-2020 Applicants in the area of the Functional Programming Laboratory (https://tinyurl.com/fp-notts) are strongly encouraged! If you are interested in applying, please contact a potential supervisor as soon as possible (the application deadline is 17th January): Thorsten Altenkirch - constructive logic, proof assistants, homotopy type theory, category theory, lambda calculus. Venanzio Capretta - type theory, mathemZZatical logic, corecursive structures, proof assistants, category theory, epistemic logic. Graham Hutton - not taking on any new students this year, but you may find these notes useful: https://tinyurl.com/scbkxkr Henrik Nilsson - functional reactive programming, domain- specific languages, generalised notions of computation. These positions are only open to international applicants. An advert for UK/EU applicants will be posted in January 2020. Best wishes, Graham +-----------------------------------------------------------+ 10 Fully-Funded International PhD Studentships School of Computer Science University of Nottingham, UK https://tinyurl.com/10-phds-2020 Applications are invited for 10 fully-funded international PhD studentships in the School of Computer Science at the University of Nottingham, starting on 1st October 2020. The topics for the studentships are open, but should relate to the interests of one of the School’s research groups: Agents Lab; Computational Optimisation and Learning Lab; Computer Vision Lab; Functional Programming; Intelligent Modelling and Analysis; Mixed Reality Lab; Data Driven Algorithms, Systems and Design and Uncertainty in Data and Decision Making The studentships are for three and a half years and include a stipend of £15,009 per year and tuition fees. Applicants are normally expected to have a first-class Masters or Bachelors degree in Computer Science or a related discipline, and must obtain the support of a potential supervisor in the School prior to submitting their application. Initial contact with supervisors should be made at least two weeks prior to the closing date for applications. Successful applicants are expected to apply for an International VC Scholarship. Informal enquiries may be addressed to Kathleen.Fennemore(a)nottingham.ac.uk. To apply, please submit the following items by email to: Marc.Williams(a)nottingham.ac.uk: (1) a copy of your CV, including your actual or expected degree class(es), and results of all University examinations; (2) an example of your technical writing, such as a project report or dissertation; (3) contact details for two academic referees. (4) a research proposal – max 2 x sides A4 You may also include a covering letter but this is optional. Closing date for applications: Friday 17 January 2020. +-----------------------------------------------------------+ This message and any attachment are intended solely for the addressee and may contain confidential information. If you have received this message in error, please contact the sender and delete the email and attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. Email communications with the University of Nottingham may be monitored where permitted by law.

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[ANN] Call for Participation: BOB 2020 (February 28, Berlin)
by Stefan Wehr 16 Dec '19

16 Dec '19

================================================================================ BOB 2020 Conference “What happens if we simply use what’s best?” February 28, 2020, Berlin http://bobkonf.de/2020/ Program: http://bobkonf.de/2020/en/program.html Registration: http://bobkonf.de/2020/en/registration.html ================================================================================ BOB is the conference for developers, architects and decision-makers to explore technologies beyond the mainstream in software development, and to find the best tools available to software developers today. Our goal is for all participants of BOB to return home with new insights that enable them to improve their own software development experiences. The program features 14 talks and 8 tutorials on current topics: http://bobkonf.de/2020/en/program.html The subject range of talks includes functional programming, formal methods, architecture documentation, functional-reactive programming, and language design. The tutorials feature introductions to Idris, Haskell, F#, TLA+, ReasonML, and probabilistic programming. Heather Miller will give the keynote talk. Registration is open online: http://bobkonf.de/2020/en/registration.html NOTE: The early-bird rates expire on February 19, 2020! BOB cooperates with racketfest and :clojureD on the day before/after BOB: https://racketfest.com/ https://clojured.de/

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Why many .tix files are generated in Haskell Program Coverage
by F L 16 Dec '19

16 Dec '19

I am using Haskell Program Coverage (HPC) to collect coverage information for Pandoc (https://github.com/jgm/pandoc) However, after adding the -fhpc option to GHC and running the program, two .tix files are generated. One is test-pandoc.tix in the main directory and the other is pandoc.tix under the "test" directory (test/pandoc.tix). These two files have different contents and I just cannot see the meaning of them from their names. Moreover, I tried to execute "hpc show xxx.tix" for them and test/pandoc.tix gives "hpc: hash in tix file for module Main does not match hash in ./.hpc/Main.mix". So, I wonder the specific generation rules of HPC tix files (possibly including the number and location) and how I can get the correct coverage information. Thanks very much!

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