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GHC 8.0.1 Compile time regression + Trac ticketprivileges

haskell-cafe - Tue, 05/24/2016 - 1:36pm
[x-post from Reddit reply] Thanks so much for all the hard work! Unfortunately I have a compile time performance regression to report on my FLTKHS <> library. I also don't have a minimal example. There is a demo that took about 15 seconds compile and link in 7.10.3, but with no changes now takes over a minute in 8.0.1. I've reproduced this across machines and operating systems. Since there was interest expressed in using this example as a benchmark if any GHC devs are still willing to help, I'm willing to walk them through getting the library set up etc. It's not a long process. The tip of my Github branch has been updated to build with GHC 8.0.1. I made myself a Trac account but apparently I don't have Ticket privileges so it won't let me create one. My username is 'deech'. Thanks! -deech _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
Categories: Offsite Discussion

Stack build with GHC 8?

haskell-cafe - Tue, 05/24/2016 - 9:10am
Hi, My name appears in the Stackage GHC 8 mega-issue [] and I'd like to upgrade my packages. I suspect it's just a case of relaxing the upper bound on base to <4.10 but I'd quite like to check that this does, in fact, work. However I'm not sure how to go about doing this since there don't yet seem to be any stackage snapshots that use GHC 8. What's the best way to get around this? Cheers, David _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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CFP: ACM MobiWac 2015 - November 13 - 17, 2016, Malta

General haskell list - Mon, 05/23/2016 - 7:16pm
** We apologize if you receive multiple copies of this message ** ================================================================== The 14th ACM International Symposium on Mobility Management and Wireless Access (MobiWac 2016) (in conjunction with the 19th ACM MSWiM) November 13 - 17, 2016 - Malta ================================================================== The 14th ACM International Symposium on Mobility Management and Wireless Access (MobiWac 2016) will be held in conjunction with MSWiM 2016 (the 19th ACM International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems) from November 13 to 17, 2016 in Malta. The MOBIWAC series of events are intended to provide an international forum for the discussion and presentation of original ideas, recent results and achievements by research
Categories: Incoming News

Call for papers: 21th International Conference on Engineering of Complex Computer Systems (ICECCS 2016), Dubai, United Arab Emirates, November 6-8 2016

General haskell list - Mon, 05/23/2016 - 12:28pm
21th International Conference on Engineering of Complex Computer Systems (ICECCS 2016) || November 6-8, Dubai, United Arab Emirates || Overview --------------------- Over the past several years, we have seen a rapid rising emphasis on design, implement and manage complex computer systems to help us deal with an increasingly volatile, globalised complex world. These systems are critical for dealing with the Grand Challenge problems we are facing in the 21st century, including health care, urbanization, education, energy, finance, and job creation. The complex computer systems are frequently distributed over heterogeneous networks and processing large amount data. Performance, real-time behavior, fault tolerance, security, adaptability, development time and cost, long life concerns are the key issues. The goal of this conference is to bring together industrial, academic, and government experts, from a variety of user domains
Categories: Incoming News

Help moving a bounds check into a case branch

haskell-cafe - Mon, 05/23/2016 - 4:27am
Sorry for the terrible subject line, but I'm a but stuck here. A couple days ago I overhauled Data.Sequence.splitAt, greatly improving its performance. You can see the new implementation at . There's one spot where I'm still stuck, however. Much like the original implementation, I check that the splitting index is before the end of the sequence (to ensure correctness). I go further, in fact, checking that the splitting index is positive, in order to avoid allocating a new tree-top in a trivial split. Logically, this check should be moved into the Deep case branch in splitTreeE, to avoid pattern matching on the top of the tree twice and performing redundant comparisons. However, when I make that move, the split/append benchmark gets worse. When I looked at the Core, it seemed that I confused GHC somehow. I ended up with a join point taking an extra argument that it totally ignored. I can fix that bench
Categories: Offsite Discussion

Representation of 3-D objects in non-continuous space

haskell-cafe - Sun, 05/22/2016 - 6:57pm
I've been poking at the problem that I've talked about in the following threads.!searchin/haskell-cafe/michael$20litchard|sort:date/haskell-cafe/n0Tc29UUgoQ/iitt3z3PCwAJ!searchin/haskell-cafe/michael$20litchard|sort:date/haskell-cafe/qD2kaZ9qpEA/jTDAp8KoCgAJ And my misguided conclusions here!topic/haskell-cafe/PMtYhVQ5nNQ I'm trying to write a clone in haskell of the space-system implemented in The biggest error in my thinking so far is assuming I could do without spatial extent. Nope, these objects in space will have to have spatial extent. So no octree for me. The advice and comments from the first two threads prompted me to investigate R-trees. I could only find specifics about how to describe 2-D. Until I found this paper on layered R-Trees. This looks like what I want. Here's my re-formulation of the c
Categories: Offsite Discussion

Going insane over overlapping instances

haskell-cafe - Sun, 05/22/2016 - 6:05pm
This is driving me nuts. So I have a type class HasStructParser I've defined. Details are irrelevant except that if you have HasStructParser defined, then ToJSON is also defined. So I have: instance HasStructParser s => ToJSON s where ... But now, any type that defines ToJSON any other way causes an Overlapping Instances error to happen- the conflict being between the real ToJSON implementation and the one deriving from HasStructParser- this despite the fact that there is no implementation for HasStructParser for the given type. Now, I don't want to allow Overlapping Instances because if there are *real* overlapping instances, I want that to be an error. For instance, if a structure did implement HasStructParser and some other implementation of ToJSON, I want to know. I suppose I could go: newtype JSON a = JSON a instance HasStructParser s => ToJSON (JSON s) where ... But this strikes me as being ugly- now I have to add pointless JSON constructors everywhere I want to convert to
Categories: Offsite Discussion

ANNOUNCE: testbench-

haskell-cafe - Sun, 05/22/2016 - 3:23pm
I've just released a new library onto Hackage that aims to help you writing comparison-oriented benchmarks by: a) reducing the duplication found when using criterion directly b) let you test your benchmarked values/functions to ensure that they have the same result/satisfy a given predicate c) provide more comparison-oriented output I've written more about it here: Or you could go straight to the Hackage page here:
Categories: Offsite Discussion

Interacting with Java in GHCVM

haskell-cafe - Sun, 05/22/2016 - 3:54am
Hi Haskell-Cafe, I've been working on a JVM backend for GHC [1] and I took some time to flesh out a design for the Java FFI [2] which will pretty much decide whether the project will be useful or not. I would love feedback from the community on how to improve the design or requests for important interop features that I have neglected. Thanks, Rahul Muttineni [1] [2] _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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Haskell Meetup group in Delhi, India

haskell-cafe - Sat, 05/21/2016 - 7:44am
Hi all, I just started a meetup group for Haskellers in and around Delhi NCR, India. The plan is to organise regular (monthly) meetups, talks, workshops etc for Haskell / FP enthusiasts at all skill levels. Anyone interested is welcome to join at - Also, since we are just getting started, the best way to help right now would be to spread the word! Thanks, Anupam Jain
Categories: Offsite Discussion

Proposal: add fromRight and fromLeft to Data.Either

libraries list - Fri, 05/20/2016 - 9:08pm
When working with Either, I am often missing two simple functions: fromRight :: Either a b -> b fromLeft :: Either a b -> a It has been implemented a couple of times: But I don't want to depend on yet another library for such a basic function. Could it be added? Anton
Categories: Offsite Discussion

Modeling space for a MUD - revisited.

haskell-cafe - Fri, 05/20/2016 - 5:47pm
This is a continuation of a conversation started in the following two links.!searchin/haskell-cafe/michael$20litchard|sort:date/haskell-cafe/n0Tc29UUgoQ/iitt3z3PCwAJ!searchin/haskell-cafe/michael$20litchard|sort:date/haskell-cafe/qD2kaZ9qpEA/jTDAp8KoCgAJ I am trying to model a 3-D space for a mudlike. Here's the criteria I have so far: (1) Objects in space will be either ships that can move or stationary things like non-moving game-controlled ships, space-stations , moons and planets. (2) Objects will not have spatial extent (3) Space is non-continuous (4) Collision happens only when one object is stationary or each moving objects are moving directly toward each other, on the same line. (5) Movement happens by setting a destination vector and a speed. There's no steering exactly, but you can change destination while moving, slow down or stop suddenly. (6) Octree looks like the data structure I want to use for modeling. I'm looking a
Categories: Offsite Discussion

ANNOUNCE: accelerate-typelits

haskell-cafe - Thu, 05/19/2016 - 11:16pm
I want to announce my first haskell project big/clean enough so I consider it possibly useful to others - accelerate-typelits is a library that provides vectors/matrices in a typesafe way - i.e. The dimension of the entities are stored on type level as (Nats). There is basic vector/matrix functionality, documentation and tests for those functions (mostly properties). If I have time I will provide some basic examples and a bit more complicated example within the next week. It is available on hackage as well as on github I would be happy to get some feedback. - Martin _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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DSLDI 2016: Call for Talk Proposals

General haskell list - Thu, 05/19/2016 - 10:24pm
********************************************************************* CALL FOR TALK PROPOSALS DSLDI 2016 Fourth Workshop on Domain-Specific Language Design and Implementation October 31, 2016 Amsterdam, Netherlands Co-located with SPLASH ********************************************************************* Deadline for talk proposals: August 1, 2016 *** Workshop Goal *** Well-designed and implemented domain-specific languages (DSLs) can achieve both usability and performance benefits over general-purpose programming languages. By raising the level of abstraction and exploiting domain knowledge, DSLs can make programming more accessible, increase programmer productivity, and support domain-specific optimizations. The goal of the DSLDI workshop is to bring together researchers and practitioners interested in discussing how DSLs should be designed, implemented, supported by tools, and applied in realistic contexts. The focus of the w
Categories: Incoming News

ANNOUNCE: Sifflet 2.3.0 - recursion learning aid / visual programming language

haskell-cafe - Thu, 05/19/2016 - 7:12pm
Sifflet 2.3.0 is now available on Hackage. This release brings Sifflet up to date, so it compiles with GHC 7.10.3, newer versions of depended-on libraries, and builds in a cabal sandbox. Sifflet is the visual, functional programming language and support system for students learning about recursion. Sifflet programmers define functions by drawing diagrams, and the Sifflet interpreter uses the diagrams to show how function calls are evaluated. The Sifflet library (formerly sifflet-lib package) is reintegrated into, and deprecated in favor of, the sifflet package. A test suite is added. Personal Note ------------- It's been about 18 months since I've been able to work on this project or do any serious Haskell development. A lot has changed in the Haskell world -- a lot of catching up to do! It feels good getting back to Haskell again. About Sifflet ------------- Sifflet is a visual, functional programming language intended as an aid for learning about recursion. * A picture explains Sifflet better
Categories: Offsite Discussion

CFP (Approaching Deadline): IEEE DS-RT 2016 - SpecialSession tracks

General haskell list - Thu, 05/19/2016 - 3:37pm
Dear Colleagues and Researchers, Apologies, if you have received multiple copies of this CFP. ********** CALL FOR PAPER ********** 20th IEEE/ACM* International Symposium on Distributed Simulation and Real Time Applications September 21 - 23, 2016, London, UK *IEEE/ACM Pending Upon Approval DS-RT 2016 is running four special sessions this year: - Simulation of Urban Traffic Management and ITS - Distributed Simulations of Distributed Systems - Augmented and Virtual Reality for Real-Time Applications - Agent-based Modeling and Simulation Those special sessions cover prominent areas of the field of distributed simulations and real time applications, and many papers were accepted in previous editions of DS-RT on the same topics. See below for more detailed descriptions of those special sessions. Authors of selected papers will be invited to submit extended versions of their papers to a special issue on "Data-driven and Large-scale Distributed Simulation"
Categories: Incoming News

Proposal: add full complement of support for decreasing things in Data.Map

libraries list - Thu, 05/19/2016 - 3:00pm
Data.Map offers functions to convert from ascending lists to maps, and also offers a function to map an increasing function over the keys of a map. Equivalents for descending lists and decreasing functions are missing. I think we should add them. Any objections? _______________________________________________ Libraries mailing list Libraries< at >
Categories: Offsite Discussion

[ANN] Final Call for Papers: Erlang Workshop 2016 -- Submission deadline (3 June) approaching

General haskell list - Thu, 05/19/2016 - 12:28pm
Apologies for any duplicates you may receive. CALL FOR PAPERS =============== Fifteenth ACM SIGPLAN Erlang Workshop ------------------------------ ----------------------------- Nara, Japan, September 23, 2016 Satellite event of the 21st ACM SIGPLAN International Conference on Functional Programming (ICFP 2016) September 18-24, 2016 The Erlang Workshop aims to bring together the open source, academic, and industrial communities of Erlang, to discuss technologies and languages related to Erlang. The Erlang model of concurrent programming has been widely emulated, for example by Akka in Scala, and even new programming languages were designed atop of the Erlang VM, such as Elixir. Therefore we would like to broaden the scope of the workshop to include systems like those mentioned above. The workshop will enable participants to familiarize themselves with recent developments on new techniques and tools, novel applications, draw lessons from users' experiences and identify research problems and common areas
Categories: Incoming News

RV 2016, Deadline for abstract on May 20 (AoE)

General haskell list - Thu, 05/19/2016 - 10:41am
Following several requests, the deadlines have been extended as follows: - Abstract deadline: Friday May 20 (AoE). - Paper and tutorial deadline: Friday May 27 (AoE). =============================================== RV 2016 16th International Conference on Runtime Verification September 23-30, Madrid, Spain <> Scope Runtime verification is concerned with monitoring and analysis of software and hardware system executions. Runtime verification techniques are crucial for system correctness, reliability, and robustness; they are significantly more powerful and versatile than conventional testing, and more practical than exhaustive formal verification. Runtime verification can be used prior to deployment, for testing, verification, and debugging purposes, and after deployment for ensuring reliability, safety, and security and for providing fault containment and recovery as well as online system repair. Topics of interest to the conference include: - specification
Categories: Incoming News

Proposal reminder: Add functions to get consecutive elements to Data.List

libraries list - Thu, 05/19/2016 - 6:27am
The discussion period for this proposal is near (31 of May). So far I count 1 for and 2 against the proposal. Joachim Breitner made a good enumeration of some advantages of adding these to base. Here is an enumeration of pros: * Availability in Data.List gives this pattern a common name. * A common name for this makes code easier to read and decreases the risk of getting the definition wrong. * The argument won't have to be repeated, hence making it easier to chain the functions. * List-fusion potential. Tobias Florek pointed out that `zip <*> tail` can be used to define this inline without the need for repeating the argument and made a reference to the Fairbairn threshold. This is elegant, but I am afraid that people might consider this obscure code golfing if used. Cheers Johan Holmquist ---------- Forwarded message ---------- From: Henning Thielemann <lemming< at >> Date: 2016-04-13 13:28 GMT+02:00 Subject: Re: Proposal: Add functions to get consecutive elements to Data.List To:
Categories: Offsite Discussion