[Haskell] Haskell dev role in Strats at Standard Chartered London
I'm hiring another Haskell dev to join the Strats team in London. Details here: https://donsbot.wordpress.com/2015/06/15/haskell-dev-role-in-strats-at-standard-chartered-london-2/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] VISSOFT 2015 - Call for Papers: New Ideas or Emerging Results and Tool Demos
--- VISSOFT 2015 - Call for Papers: New Ideas or Emerging Results and Tool Demos 3rd IEEE Working Conference on Software Visualization (VISSOFT) September 27-28, 2015, Bremen, Germany Paper submission date: June 29, 2015 Notification: July 31, 2015 http://vissoft.info Software visualization is a broad research area encompassing concepts, methods, tools, and techniques that assist in a range of software engineering and software development activities. Covered aspects include the development and evaluation of approaches for visually analyzing software and software systems, including their structure, execution behavior, and evolution. The VISSOFT IEEE Working Conference on Software Visualization continues the history of the ACM SOFTVIS Symposium on Software Visualization and the IEEE VISSOFT International Workshop on Visualizing Software for Understanding and Analysis. The conference focuses on visualization techniques that target aspects of software maintenance and evolution, program comprehension, reverse engineering, and reengineering, i.e., how visualization helps professionals to understand, analyze, test and evolve software. We aim to gather tool developers, experts, users, and researchers from software engineering, information visualization, computer graphics, and human-computer interaction to discuss theoretical foundations, algorithms, techniques, tools, and applications related to software visualization. Topics of interest include, but are not limited to: * Innovative visualization and visual analytics techniques for software engineering data, such as, - source code - static and dynamic dependencies - software evolution and repositories - software documentation - web services - protocol, log, and performance data - parallel techniques - database schemes - software security and privacy issues - workflow and business processes * Visualization to support program comprehension, software testing, and debugging * Interaction techniques and algorithms for software visualization * Visualization-based techniques in computer science and software engineering education * Integration of software visualization tools and development environments * Empirical evaluation of software visualization * Industrial experience on using software visualization VISSOFT features a New Ideas or Emerging Results (NIER) track and a Tool Demo track related to the list of topics suggested above. Papers are solicited that present original, unpublished research results and will be rigorously reviewed by an international program committee. The NIER contributions (New Ideas and Emerging Results) describe work-in-progress and preliminary exciting results. Authors should include open questions and even provocative hypotheses to get early feedback on their research ideas or even support through new research collaborations. Tool contributions describe the design or actual utilization of software visualization tools, with a focus on relevant tool construction aspects or the use of the tool for gaining new insights. Authors should be prepared to demonstrate their tool at the conference. The submission may also contain a link to a screencast (video). All accepted submissions will appear in the conference proceedings and the IEEE Digital Library. -== How to Submit ==- Both types of papers have to be maximum 5 pages long (including bibliography and annexes). Paper submission date: June 29, 2015 (previously: June 15, 2015) Notification: July 31, 2015 Submissions must be submitted online via the VISSOFT 2015 EasyChair conference management system at https://easychair.org/conferences/?conf=vissoft2015 Please adhere to the formatting instruction published on the ICSME website: http://www.icsme.uni-bremen.de/formatting.php -== Organizing Committee ==- General Chair: Jürgen Doellner, Hasso-Plattner-Institut, Germany Program Co-Chairs: Fabian Beck, University of Stuttgart, Germany Alexandre Bergel, University of Chile, Chile NIER/Tool Co-Chairs: Craig Anslow, Middlesex University, UK Johan Fabry, University of Chile, Chile NIER/Tool Program Committee: Bilal Alsallakh TU Vienna, Austria Jennifer Baldwin Swinburne University,Australia Ivan Beschastnikh University of British Columbia, Canada Usman Bhatti INRIA Lille / Synectique, France Michael Burch University of Stuttgart, Germany Andrei Chis Bern University, Switzerland Neville Churcher University of Canterbury, New Zealand Marcus Denker INRIA Lille, France Coen De Roover Vrije Universiteit Brussel, Belgium Jens Dietrich Massey University, New Zealand Bogdan Dit Boise State University, US Matthias Frisch Magdeburg University, Germany Maria-Elena Froese University of Victoria, Canada Michael Homer Victoria University of Wellington, New Zealand James A. Jones University of California, Irvine, US Adrian Kuhn AirBNB, US Jannik Laval Ecole Des Mines de Douai, France Paul Leger Universidad Catolica Del Norte, Chile Andrea
RE: overlapping instances in 7.10.1
On Mon, 2015-06-15 at 09:29 +, Simon Peyton Jones wrote:
| This is why I think that ghc-7.8.3 treats the OI notion in a more
| natural way than ghc-7.10.1 does.
| May be, ghc-7.10.1 has a better technical tool for this, but ghc-
| 7.8.3 corresponds to a natural notion of OI.
|
| Can GHC return to a natural OI notion?
| Or am I missing something?
Well it all depends what you mean by natural. To me it is profoundly
un-natural to deliberately have the same type-class constraint solved in two
different ways in the same program!
To require this would prevent cross-module specialisation. If I have
f :: C a = a - a
in one module, and I specialise it to
f_spec :: [Int] - [Int]
in one module, I want to be free to re-use that specialisation in other
modules. But under your natural story, I cannot do that, because (C [Int])
might be resolved differently there.
I'd be interested in what others think. I've started
https://ghc.haskell.org/trac/ghc/ticket/10526
to collect these points.
Meanwhile, Sergei, it's clear how to fix docon, so you are no longer stuck.
I hope DoCon is not stuck -- because it relies (so far) on ghc-7.8.3.
But I need to understand the subject of overlapping instances (OI).
--
I am writing this _here_ because to clicking at
https://ghc.haskell.org/trac/ghc/ticket/10526
my browser responds Problem occurred while loading the URL
https://ghc.haskell.org/trac/ghc/ticket/10526
SSL handshake failed: A TLS fatal alert has been received.
Then, I start searching from https://ghc.haskell.org/trac/ghc/
and cannot find #10526
Also I had earlier a certain difficulty with registering to this bug
tracker, and suspect that registration was not fully successful, so that
I doubt that I can write there.
May I, please, discuss the subject here?
---
The report of 7.10.1-errReport-may23-2015.zip
shows that 7.8.3 and 7.10.1 treat OI differently,
But this report is rather complex.
Instead consider the following simple example.
module A where
class Size a where size :: a - Int
instance {-# OVERLAPPING #-}
Size [a] where size = length
f :: Size a = a - Int
f = size
g :: [Maybe Int] - Int
g = size
module Main where
import A
instance {-# OVERLAPPING #-}
Size [Maybe a] where size _ = -1
mbs = [] :: [Maybe Int]
main = putStr (shows (f mbs) \n) -- I -1
-- putStr (shows (g mbs) \n) -- II 0
Making and running in ghc-7.10.1 :
ghc --make -XFlexibleInstances Main
./Main
It prints -1 for the line (I) for main,
and0 for the line (II).
To compare to ghc-7.8.3, comment out the pragma and add
-XOverlappingInstances to the ghc call.
And this yields the same results -1 and -0 respectively.
Please, how to change (a bit) the above simple example in order to see
the difference between 7.8.3 and 7.10.1
?
Thanks,
--
Sergei
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Re: ANNOUNCE: GHC 7.10.2 Release Candidate 1
Not in particular - I guess we didn't get everything we precisely needed for the RC. I've filed a ticket: #10530 On Sun, Jun 14, 2015 at 10:25 PM, Andrés Sicard-Ramírez a...@eafit.edu.co wrote: On 14 June 2015 at 19:16, Austin Seipp aus...@well-typed.com wrote: We are pleased to announce the first release candidate for GHC 7.10.2: Since transformers is a GHC-include library, is there any particular reason why GHC 7.10.2 RC1 didn't include the latest version of the transformers library, i.e. transformers-0.4.3.0? -- Andrés -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
Re: ANNOUNCE: GHC 7.10.2 Release Candidate 1
On 15 June 2015 at 09:16, Austin Seipp aus...@well-typed.com wrote: We are pleased to announce the first release candidate for GHC 7.10.2: Thank you I did a 'quick' build of it for Fedora 22 in my Copr repo: https://copr.fedoraproject.org/coprs/petersen/ghc-7.10.2 I will try to update it to a 'perf' build soon. Cheers, Jens ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
Re: ANNOUNCE: GHC 7.10.2 Release Candidate 1
Yes, as noted on the ticket, I've bumped the priority and we'll be looking into this - and hopefully have a fix in time for 7.10.2. There are some similar tickets where we get large explosions of terms, so it may be in the same ballpark. On Sun, Jun 14, 2015 at 11:18 PM, Rob Everest rober...@cse.unsw.edu.au wrote: We plan to make the 7.10.2 final release at the end of this coming week - so please test as much as possible; bugs are much cheaper if we find them before the release! Could I possibly draw attention to #10491? It's a regression in the simplifier that is causing considerable pain for Accelerate, namely a compile time of many hours for a 300 line module. It would be unfortunate if this couldn't be resolved for the 7.10.2 release. -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
Re: ANNOUNCE: GHC 7.10.2 Release Candidate 1
Thanks. GHC 7.10.2-rc1 can now be installed with Halcyon: halcyon install --ghc-version=7.10.2-rc1 --cabal-version=1.22.4.0 Supported platforms include: - Amazon Linux 2014.09 - Arch Linux - CentOS 6, 7 - Debian 6, 7, 8 - Gentoo Linux - openSUSE 13.2 - OS X 10.8, 10.9, 10.10 - Red Hat Enterprise Linux 6, 7 - Slackware 14.1 - SUSE Linux Enterprise Server 12 - Ubuntu 12.04 LTS, 14.04 LTS, 14.10, 15.04 - Fedora 20, 21 -- Miëtek https://mietek.io On 2015-06-15, at 01:16, Austin Seipp aus...@well-typed.com wrote: We are pleased to announce the first release candidate for GHC 7.10.2: https://downloads.haskell.org/~ghc/7.10.2-rc1 https://downloads.haskell.org/~ghc/7.10.2-rc1/docs/html/ This includes the source tarball and bindists for Windows, Mac OS X, and Debian Linux. FreeBSD and Solaris binaries will follow soon. These binaries and tarballs have an accompanying SHA256SUMS file signed by my GPG key id (0x3B58D86F). We plan to make the 7.10.2 final release at the end of this coming week - so please test as much as possible; bugs are much cheaper if we find them before the release! -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ ___ ghc-devs mailing list ghc-d...@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs smime.p7s Description: S/MIME cryptographic signature ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
RE: overlapping instances in 7.10.1
On Mon, 2015-06-15 at 09:29 +, Simon Peyton Jones wrote:
| This is why I think that ghc-7.8.3 treats the OI notion in a more
| natural way than ghc-7.10.1 does.
| May be, ghc-7.10.1 has a better technical tool for this, but ghc-
| 7.8.3 corresponds to a natural notion of OI.
|
| Can GHC return to a natural OI notion?
| Or am I missing something?
Well it all depends what you mean by natural. To me it is profoundly
un-natural to deliberately have the same type-class constraint solved in
two different ways in the same program!
To require this would prevent cross-module specialisation. If I have
f :: C a = a - a
in one module, and I specialise it to
f_spec :: [Int] - [Int]
in one module, I want to be free to re-use that specialisation in other
modules.
But under your natural story, I cannot do that, because (C [Int]) might be
resolved differently there.
Now, I give a simple (and a very contrived) example illustrating of how
overlapping instances (OI)
are used in DoCon.
Also this example is made after the sample that Simon has given in his
recent letter:
GHC generally assumes that if it generates
(the instance)
(C T) in one place, then it can use that anywhere in the program that
(C T) is needed. That is, there is only one (C T) dictionary.
But suppose you have overlapping instance in different modules; say
module A where instance C [a]
module B where import A; instance C [Maybe a]
If you use (C [Maybe Int]) in A, then of course we won’t see the
instance in B. So you’ll get a different dictionary than if you
compute C [Maybe Int] in module B.
In short, overlapping instances are OK, but it’s best to put them in
the same module as the instances they overlap.
My example:
module A where
class Att a where att :: a - (Int , Maybe Int)
instance {-# OVERLAPPING #-}
Att [a] where att xs = (length (reverse xs) , Nothing)
f :: [Maybe Int] - (Int , Maybe Int)
f = att
-
module Main where
import A
instance {-# OVERLAPPING #-}
Att [Maybe a] where att mbs = (length mbs , Just 1)
mbs = [] :: [Maybe Int]
main = putStr (shows (f mbs) \n) -- (I) (0 , Nothing)
-- putStr (shows (att mbs) \n) -- (II) (0, Just 1)
--
Att stands for the class C of Simon's letter.
It means certain attributes of a value, and also of its type.
The value Nothing for the second part of (att a) means that the second
component of attributes is not definitely known for this particular
instance.
length (reverse xs) imitates a non-optimal method for computing att
in the instance for a = [a]. This instance is very general, so that
the first component of attributes is evaluated in-efficiently (but
correct), the second component has a correct value, but highly
indefinite (few information derived).
The function f uses the instance Att [Maybe Int],
and it is satisfied with the generic instance given in A.hs.
Because a) at this stage of the project there is not enough
functionality to implement a better special method b) for this
particular case in this module the generic instance is sufficient.
Main.hs defines a special instance of Att for [Maybe a].
This instance in more special than the one defined in A.hs.
And the value (att mbs) has the first component evaluated more
efficiently than for the generic (Att [a]) instance. But the value is
the same.
The second component even has a different value in the result. But it is
considered as correct
(this is similar to the situation of:
generally the speed is 2 s 8,
and in this the special case it is 3).
The call (att mbs) in `main' uses a different dictionary for Att
than the call A.f (mbs).
Right?
Both ghc-7.8.3
(with -XFlexibleInstnce -XOverlappingInstances in the call)
and ghc-7.10.1
(with -XFlexibleInstnce in the call)
give the same results in 'main':
(0, Nothing) for the line (I)
and
(0, Just 1) for the line (II).
And I thought that everything is set naturally in this program.
Simon, you would state that
as A.f and (Main.att mbs) use the instances of Att for the
same type [Maybe Int],
overlapping instances are OK, but it’s best to put them in the same
module as the instances they overlap.
I do not understand the grammar of the phrase in quotes, either it has a
typo or this is too difficult English for me.
Anyway: does this mean for this particular example, that it is highly
desirable to set the two above instance declarations in the same module
?
1) What if they are in different modules, like in the above example.
What unnatural may happen -- for example?
2) At least ghc-7.8.3 and ghc-7.10.1 do the same in this example.
May be, you can change this example a bit to make ghc-7.8.3 and
ghc-7.10.1 diverse, so that my
[Haskell] Summer School on Generic and Effectful Programming (2nd call for participation)
Call for Participation SUMMER SCHOOL ON GENERIC AND EFFECTFUL PROGRAMMING St Anne's College, Oxford, 6th to 10th July 2015 http://www.cs.ox.ac.uk/projects/utgp/school/ TOPIC Generic programming is a technique that exploits the inherent structure that exists in data, to automatically produce efficient and flexible algorithms that can be adapted to suit different needs. The goal of this school is to explore datatype-generic programming and related topics from a variety of different angles, emphasizing in particular the interplay of generics and effects. This summer school is the closing activity of the EPSRC-funded project Unifying Theories of Generic Programming at Oxford University. LECTURERS Six lecturers from the Programming Languages community, each an acknowledged expert in their specialism, will cover various aspects of generic and effectful programming. Each will give about four hours' lectures, distributed throughout the week. Edwin Brady (University of St Andrews) Embedded Domain-Specific Languages in Idris Fritz Henglein (University of Copenhagen) Worst-case Efficient Generic Functional Programming on Bulk Data Andres Löh (Well-Typed) Applying Type-level and Generic Programming in Haskell Conor McBride (University of Strathclyde) Datatypes of Datatypes Don Syme (Microsoft Research) Compile-time Meta-programming for the Information-rich World Tarmo Uustalu (Tallinn University of Technology) Containers for Effects and Contexts PREREQUISITES The school is aimed at doctoral students in programming languages and related areas; however, researchers and practitioners will be very welcome, as will strong masters students with the support of a supervisor. It will be assumed that participants have a good understanding of typed functional programming, as in Haskell, O'Caml, or F#. DATES Registration deadline: 21st June 2015 School:6th July (9am) to 10th July 2015 (lunchtime) COSTS Costs will be kept low, thanks to support from EPSRC. There will be a nominal registration fee of £135, and BB accommodation in college will be £75 (ensuite) or £48 (shared bathroom) per night. We can accept at most 50 participants; places will be allocated on a first-come, first-served basis. FURTHER INFORMATION Further information, including instructions on how to register, is available at the website: http://www.cs.ox.ac.uk/projects/utgp/school/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
