Re: [Haskell-cafe] Poll: Do you want a mascot?

No. Am Mittwoch, den 23.11.2011, 13:11 -0600 schrieb heathmatlock: > Question: Do you want a mascot? > > > Answers: > Yes > No > > > > > -- > This is an attempt to figure out if this idea is going anywhere. > ___ > Haskell-Cafe mailing list > Hask

Re: [Haskell-cafe] A Mascot

Am Mittwoch, den 16.11.2011, 10:46 +0100 schrieb Bas van Dijk: > Is ⊥ the right symbol to express the non-strict evaluation of the > language? Is it true that non-strict evaluation requires that ⊥ > inhabits every type? In typical strict languages, ⊥ also inhabits every type. The difference is tha

[Haskell-cafe] package cache being out of date

Hi, I have a freshly installed Haskell Platform 2010.2.0.0 on Windows 7. When I run ghc-pkg list, I get the following message (besides the expected package info): WARNING: cache is out of date: C:/Program Files (x86)/Haskell Platform/2010.2.0.0\lib\package.conf.d\package.cache use 'g

Re: [Haskell-cafe] H98, OOHaskell - getting started with objects in Haskell

Am Sonntag, den 16.01.2011, 14:48 -0800 schrieb gutti: > Looking at life u probably could save time, if u only would evaluate > code on cells, where the neighbors have changed status. So rather than > triggering them all centrally and each checks its neighbours, we could > use the concept: > > -

Re: [Haskell-cafe] H98, OOHaskell - getting started with objects in Haskell

Am Donnerstag, den 13.01.2011, 15:23 -0800 schrieb gutti: > I'm especially interestes in engineering calculation tasks where cellular > automata could be used. In that case all u have to do is to give the class > the right properties and that "let it grow". > > Such a localised intelligence appro

Re: [Haskell-cafe] Improving HList programming/debugging (longish)

Am Dienstag, den 11.01.2011, 20:05 -0500 schrieb jeff p: > This message shows how to slightly reformulate HLists (and other > type-level things) to get better type-checking and more informative > error messages. The technique is interesting in that it uses GADTs and > functional dependencies and se

Re: [Haskell-cafe] record update

Am Dienstag, den 14.09.2010, 13:31 -0600 schrieb Jonathan Geddes: > Wow, I had no idea there were so many record packages! The trouble is that only one of them (i.e., mine) is categorized under “Records” on Hackage. Best wishes, Wolfgang ___ Haskell-Ca

Re: [Haskell-cafe] Re: Coding conventions for Haskell?

Am Sonntag, den 26.09.2010, 17:25 +0100 schrieb Maciej Piechotka: > I use it in following way; > > 1. For short sharing name (rarely) > > let a = b ++ c in (a, a) > > 2. Default > > let a :: [Int] > a = b ++ c > f :: Int -> String > f 0 = "" > f x = sho

Re: [Haskell-cafe] record update

Am Samstag, den 11.09.2010, 11:21 -0600 schrieb Jonathan Geddes: > I know that record updates is a topic that has become a bit of a dead > horse, but here I go anyway: > > I find that most of the record updates I read and write take the form > > >someUpdate :: MyRecord -> MyRecord > >someUpdate m

Re: [Haskell-cafe] Haskell, arrows and signal processing

Am Mittwoch, den 08.09.2010, 11:47 -0300 schrieb Rafael Gustavo da Cunha Pereira Pinto: > The input and output are infinite streams. I have a few questions: > > 1) Is it possible to change it to use arrows? How would it look like? > 2) How would one implement an continuous time version? Have you

Re: Re[2]: [Haskell-cafe] overloaded list literals?

Am Montag, den 06.09.2010, 19:38 +0400 schrieb Bulat Ziganshin: > btw, i also had proposal to automatically convert typeclasses used in > type declarations into constraints, so that: > > putStr :: StringLike -> IO () > > treated as > > putStr :: StringLike s => s -> IO () This blurs the distincti

Re: [Haskell-cafe] overloaded list literals?

Am Montag, den 06.09.2010, 11:47 +0100 schrieb Neil Brown: > I would have thought you have two obvious choices for the type-class > (things like folding are irrelevant to overloading list literals): > > class IsList f where >fromList :: [a] -> f a > > or: > > class IsList f where >cons

Re: [Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Am Donnerstag, 11. März 2010 00:37:18 schrieb wren ng thornton: > Wolfgang Jeltsch wrote: > > Hello, > > > > some time ago, it was pointed out that generalized newtype deriving could > > be used to circumvent module borders. Now, I found out that generalized > >

Re: [Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Am Dienstag, 9. März 2010 11:53:14 schrieben Sie: > Isn't this just an extension of the notion that multi-parameter typeclasses > without functional dependencies or type families are dangerous and allow > for type-naughtiness? Multi-parameter typeclasses are dangerous? It’s the first time I hear t

Re: [Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Am Dienstag, 9. März 2010 15:54:16 schrieb Jan-Willem Maessen: > On Mar 9, 2010, at 5:53 AM, Max Cantor wrote: > > Isn't this just an extension of the notion that multi-parameter > > typeclasses without functional dependencies or type families are > > dangerous and allow for type-naughtiness? > >

Re: [Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Am Dienstag, 9. März 2010 07:24:35 schrieb Steffen Schuldenzucker: > On 03/08/2010 10:45 PM, Wolfgang Jeltsch wrote: > > The point is, of course, that such conversions are not only possible for > > binary operations but for arbitrary values and that these conversions are >

Re: [Haskell-cafe] Haskell course, training

Am Montag, 8. März 2010 23:17:56 schrieb Henning Thielemann: > On Sun, 7 Mar 2010, G?nther Schmidt wrote: > > I think I've reached the point where I need some tutoring, so provided > > I've got money for travel and course fees, and time, where do I get it? > > I'm not a student so some courses aren

Re: [Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Am Montag, 8. März 2010 22:45:19 schrieb Wolfgang Jeltsch: > Hello, > > some time ago, it was pointed out that generalized newtype deriving could > be used to circumvent module borders. Now, I found out that generalized > newtype deriving can even be used to define function

[Haskell-cafe] generalized newtype deriving allows the definition of otherwise undefinable functions

Hello, some time ago, it was pointed out that generalized newtype deriving could be used to circumvent module borders. Now, I found out that generalized newtype deriving can even be used to define functions that would be impossible to define otherwise. To me, this is surprising since I thought

Re: [Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)

Am Samstag, 6. März 2010 03:45:02 schrieb Maciej Piechotka: > PS. There is also GPL-with-linking-exception which allows linking etc. > but does not require relinking capability. I'd believe that in such case > the cross-module inlining is not a problem since it is 'linking' for > compiler. The ter

Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)

Am Donnerstag, 4. März 2010 18:57:03 schrieb MightyByte: > Interesting. It seems to me that the only solution for the > BSD-oriented haskell community is to practically boycott GPL'd > libraries. From what I understand, this is exactly what the LGPL is > for. I've known the basic idea behind the

Re: [Haskell-cafe] grapefruit on windows or osX

Am Sonntag, 21. Februar 2010 21:57:45 schrieb gladst...@gladstein.com: > I'm unable to get grapefruit going on osx or windows because (I think) I > can't get the underlying GTK installed. Hi, thank you for giving Grapefruit a try. Yes, you are most likely right that Gtk2Hs is the stumbling block

Re: [Haskell-cafe] Examples

Am Samstag, 8. August 2009 13:29 schrieb Andrew Coppin: > As some of you may remember, I recently released a couple of packages on > Hackage. I'd like to also release some example programs using these > packages, but I'm not sure of the best way to do this. > > Do I make the example programs part o

Re: [Haskell-cafe] Hackage and version control

Am Montag, 20. Juli 2009 05:25 schrieb Robin Green: > community.haskell.org requires you to wait for a volunteer to review > every new project request. However, response times are usually low. Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-

Re: [Haskell-cafe] ANN: AC-Vector, AC-Colour and AC-EasyRaster-GTK

Am Sonntag, 19. Juli 2009 23:42 schrieben Sie: > On Jul 18, 2009, at 9:26 PM, Wolfgang Jeltsch wrote: > > I don’t think, it’s a good idea to have German identifiers, since > > Haskell’s keywords are English. > > Put it this way: if Haskell's keywords were in German, do y

Re: [Haskell-cafe] is closing a class this easy?

Am Samstag, 18. Juli 2009 08:58 schrieb Miguel Mitrofanov: > Oops... Sorry, wrong line. Should be > > isAB :: forall p. p A -> p B -> p x Is this a well-known approach for closing classes? I came across the same idea and implemented a generic framework for closing classes in this way. I did this

Re: newtype deriving, was Re: [Haskell-cafe] is closing a class this easy?

Am Samstag, 18. Juli 2009 11:43 schrieb Conor McBride: > The trouble here is that somewhere along the line (GADTs? earlier?) > it became possible to construct candidates for p :: * -> * which don't > respect isomorphism. Hello Conor, I’m not sure whether I exactly understand what you mean here. I

Re: [Haskell-cafe] ANN: AC-Vector, AC-Colour and AC-EasyRaster-GTK

Am Samstag, 18. Juli 2009 06:31 schrieben Sie: > On Jul 18, 2009, at 2:35 AM, Wolfgang Jeltsch wrote: > > So I should upload a package with German identifiers to Hackage? > > Sure, why not? The fact that I can't read it is my loss, not your fault, > and there will be

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: first Grapefruit release

hat makes > for a lot more difficult coding to say the least. > > On Wed, Feb 18, 2009 at 4:17 AM, Wolfgang Jeltsch > > wrote: > > Am Dienstag, 17. Februar 2009 19:36 schrieben Sie: > >> > If you have problems with Gtk2Hs on Windows, it might be better to > >&

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: first Grapefruit release

Am Montag, 16. Februar 2009 15:27 schrieben Sie: > On Mon, 16 Feb 2009, Wolfgang Jeltsch wrote: > > [redirecting to haskell-cafe] > > > > Am Sonntag, 15. Februar 2009 00:25 schrieben Sie: > >> Hi Wolfgang, > >> > >> I was wondering if I can use

Re: [Haskell-cafe] What is the point of the 'What the bleep' names in haskell?

Am Freitag, 17. Juli 2009 21:06 schrieb Daryoush Mehrtash: > Why do Haskell programmers (and libraries) name their function like "<@<" > or "###"?Why not use a more descriptive label for functions? It’s for the same reason that mathematicians say 2 + 3 instead of plus(2,3): it’s more readable

Re: [Haskell-cafe] Pattern matching with where free variables can be used more than once

Am Freitag, 17. Juli 2009 20:38 schrieb Stefan Holdermans: > Christopher, > > > Wouldn't it be great if pattern variables could be used more than once > > in a pattern? Like so: > > > >foo [x,x,_,x] = "The values are the same!" > >foo _ = "They're not the same!" > > These are called n

Re: [Haskell-cafe] What's the status with unicode characters on haddock ?

Am Freitag, 17. Juli 2009 16:43 schrieben Sie: > On Fri, Jul 17, 2009 at 4:37 PM, Wolfgang > > Jeltsch wrote: > > To my knowledge, Haddock only supports ASCII as input encoding. If you > > want to have characters outside ASCII, you have to escape them using > > someth

Re: [Haskell-cafe] What's the status with unicode characters on haddock ?

Am Freitag, 10. Juli 2009 09:54 schrieb david48: > Hello all, > > I made a small program for my factory and I wanted to try to document > it using haddock. The thing is, the comments are in French and the > resulting html pages are unreadable because the accentuated letters > are mangled. > > It's

Re: [Haskell-cafe] ANN: AC-Vector, AC-Colour and AC-EasyRaster-GTK

Am Mittwoch, 15. Juli 2009 05:27 schrieben Sie: > On Jul 10, 2009, at 8:44 PM, Wolfgang Jeltsch wrote: > > Why do we use English for identifiers? Because English is the language of > > computer science. What English should we use? It’s tempting to say, we > > should use the or

Re: [Haskell-cafe] ANN: AC-Vector, AC-Colour and AC-EasyRaster-GTK

Am Dienstag, 7. Juli 2009 14:42 schrieb Robin Green: > On Fri, 10 Jul 2009 10:44:51 +0200 > > Wolfgang Jeltsch wrote: > > PASCAL > > uses “program”, not “programme”, > > The word program (as in computer program) is spelled program in both > British and American E

Re: [Haskell-cafe] Alternative IO

Am Samstag, 11. Juli 2009 00:16 schrieben Sie: > On Friday 10 July 2009 4:35:15 am Wolfgang Jeltsch wrote: > > I fear that this instance doesn’t satisfy required laws. As far as I > > know, the following equalities should hold: > > > > (*>) = (>>) > >

Re: [Haskell-cafe] Alternative IO

Am Freitag, 10. Juli 2009 23:41 schrieben Sie: > On Jul 10, 2009, at 4:35 AM, Wolfgang Jeltsch wrote: > > I fear that this instance doesn’t satisfy required laws. As far as > > I know, the following equalities should hold: > > > > (*>) = (>>) > > &g

Re: [Haskell-cafe] ANN: AC-Vector, AC-Colour and AC-EasyRaster-GTK

Am Freitag, 10. Juli 2009 05:26 schrieb rocon...@theorem.ca: > I find it amazing that you independently chose to spell colour with a `u'. > It makes me feel better about my choice. I have to admit that it makes me unhappy. :-( Why do we use English for identifiers? Because English is the languag

Re: [Haskell-cafe] Alternative IO

Am Donnerstag, 9. Juli 2009 15:27 schrieb Cristiano Paris: > As a joke, I wrote an instance of Alternative for IO actions: > {-# LANGUAGE ScopedTypeVariables #-} > module Main where > > import Control.Applicative > import Control.Exception > > instance Alternative IO where > empty = undefined >

Re: [Haskell-cafe] Creating a new Haskell mailing list

Am Donnerstag, 18. Juni 2009 16:21 schrieb Henning Thielemann: > Ryan Trinkle schrieb: > > Hi all, > > > > I'm interested in starting a mailing list on haskell.org > > . Who should I talk to about such things? > > Is it a mailing list related to a project? Then you may request

Re: [Haskell-cafe] GUIs, FRP, (Delimited) Continuations and Zippers

Am Samstag, 16. Mai 2009 16:18 schrieb GüŸnther Schmidt: > Hi all, > > In my app, there is one part which has a rather complicated GUI logic, > it involves n drop downs with n choices each. > > Whenever the current selection in one of the drop downs changes by user > interaction, the other (n-1) dr

Re: [Haskell-cafe] Removing mtl from the Haskell Platform

Am Mittwoch, 13. Mai 2009 01:03 schrieb rocon...@theorem.ca: > I wanted to pass this idea around the cafe to get some thoughts before > submitting a trac on this topic. > > I'd like to see the mtl removed from the Haskell Platform. > > The mtl was a tremendous step forward when it was developed. H

Re: [darcs-users] [Haskell-cafe] Darcs as undo/redo system?

Am Mittwoch, 13. Mai 2009 02:55 schrieb Trent W. Buck: > Wolfgang Jeltsch writes: > > Am Freitag, 8. Mai 2009 18:43 schrieb Jason Dagit: > >> If you wanted to work on this, I would encourage you to read more > >> about patch theory[1,2,3,4] and also try out libdarcs[

Re: [Haskell-cafe] commending "Design concepts in programming languages"

Am Freitag, 8. Mai 2009 14:31 schrieb Daniel Fischer: > Though I had no contact with algebraists in the 1980s, I also hadn’t. However, nowadays I have contact with someone who was an algebraist in the 1980s. It’s my boss (professor), by the way. :-) > > I think, also category theorists often wr

Re: [darcs-users] [Haskell-cafe] Darcs as undo/redo system?

Am Freitag, 8. Mai 2009 18:43 schrieb Jason Dagit: > If you wanted to work on this, I would encourage you to read more > about patch theory[1,2,3,4] and also try out libdarcs[5]. Is libdarcs the same as the darcs library package on Hackage (which exports the darcs API)? Best wishes, Wolfgang ___

Re: [Haskell-cafe] commending "Design concepts in programming languages"

Am Donnerstag, 7. Mai 2009 14:42 schrieb Daniel Fischer: > Of course, if centuries ago people had decided to write the argument before > the function, composition would've been defined the other way round. > They haven't. Algebraists used to write x f instead of f(x) at least in the 1980s. I think

Re: [Haskell-cafe] Interesting Thread on OO Usefulness (scala mailing list)

Am Dienstag, 5. Mai 2009 18:39 schrieb Bulat Ziganshin: > Hello Wolfgang, > > Tuesday, May 5, 2009, 8:27:17 PM, you wrote: > >> i know two problems in Haskell/GHC that require OO-loke features - > >> extensible exceptions and GUI widget types hierarchy > > > > Note that you don’t need different typ

Re: [Haskell-cafe] Interesting Thread on OO Usefulness (scala mailing list)

Am Montag, 4. Mai 2009 13:35 schrieb Bulat Ziganshin: > Hello Paolo, > > Monday, May 4, 2009, 2:05:44 PM, you wrote: > > Martin Odersky advocates the OO features of the scala language > > proposing an interesting problem where the OO approach seams > > valuable. > > i know two problems in Haskell/G

Re: [Haskell-cafe] Research in functional programming

Am Sonntag, 3. Mai 2009 23:13 schrieb Louis Wasserman: > Where might I find or submit a paper on functional data structures? > Examples I've found so far include ICFP > and the JFP , > but Google hasn't fo

Re: [Haskell-cafe] Research in functional programming

Am Montag, 4. Mai 2009 11:32 schrieb Malcolm Wallace: > TFP - Trends in Functional Programming Deadline on sunday. Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] When is it OK to create a new mailing list?

Am Samstag, 2. Mai 2009 14:11 schrieb Mads Lindstrøm: > Hi > > I wanted a mailing list for my project WxGeneric and I am wondering when > it is OK to do so? How big must the potential audience be? Is there any > kind of etiquette or guidelines? > > Here http://haskell.org/mailman/admin it says that

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Mittwoch, 22. April 2009 16:00 schrieb Patai Gergely: > This also means that if you want to restart a signal without external > dependencies using a latcher, you have to inject some bogus dependency > to prevent memoisation. If the new signal depends on some others, > latching should behave intu

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Dienstag, 21. April 2009 17:18 schrieb Patai Gergely: > > What about evaluation time? If I remember correctly, the values > > of signals depend on the time when the signal expressions are > > evaluated. So evaluating them multiple times might lead to > > different behavior. Is this correct? > >

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Donnerstag, 16. April 2009 10:06 schrieb Patai Gergely: > unsafePerformIO is apparently never inlined, i.e. each instance is > executed once, so sharing works as desired But expressions that use unsafePerformIO might get inlined. > CSE is no problem either, it even helps if it's performed (and

Re: [Haskell-cafe] Non-atomic "atoms" for type-level programming

Am Dienstag, 14. April 2009 20:01 schrieb Tillmann Rendel: > How is the need for a common import for 'data TTrue; data TFalse' > different then the need for a common import for 'data Bool = True | False'? Why not say data True data False, instead of data TTrue data TFalse? I

Re: [Haskell-cafe] Re: ANN: Elerea, another FRP library

Am Mittwoch, 15. April 2009 09:03 schrieb Achim Schneider: > I don't think using dirty tricks to implement FRP deserves flak, at > all, from my POV, it sounds like complaining that the IO monad is > implemented using C... meaning that if you're that close to bare > thunks, you have every right to u

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Samstag, 11. April 2009 16:57 schrieb Patai Gergely: > > Any idea how Elerea compares to Grapefruit? It's great to see a lot of > > competition in the FRP arena, but I hope in the end this results in a > > really usable and scalable FRP system for Haskell :-) > > I think Wolfgang can judge this

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Dienstag, 14. April 2009 11:33 schrieb Patai Gergely: > and then the integration of a Grapefruit-like and a Reactive-like system > could be the ultimate solution in the long run. What do you think, Grapefruit is lacking, compared to Reactive? Best wishes, Wolfgang _

Re: [Haskell-cafe] ANN: Elerea, another FRP library

Am Freitag, 10. April 2009 18:41 schrieb Patai Gergely: > is based on some unsafePerformIO dark magic (that might easily break > depending on many factors) I wonder if this breaks referential transparency. Say, you define a signal s and use s twice in some expression. s may be evaluated once and

Re: [Haskell-cafe] Re: categories and monoids

Am Donnerstag, 19. März 2009 13:58 schrieben Sie: > An easier idea to think about would be to categorize most adjectives > applied to mathematical constructs into traits and cotraits. > > A trait refines a notion and a cotrait broadens the definition. > > When talking about a commutative ring, comm

Re: [Haskell-cafe] Re: categories and monoids

Am Mittwoch, 18. März 2009 15:17 schrieben Sie: > Wolfgang Jeltsch schrieb: > > Okay. Well, a monoid with many objects isn’t a monoid anymore since a > > monoid has only one object. It’s the same as with: “A ring is a field > > whose multiplication has no inverse.” One usuall

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Donnerstag, 19. März 2009 03:53 schrieb Benjamin L.Russell: > Therefore, rank 1 is the best. This is quite the opposite of what Denis Bueno said. :-( Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Mittwoch, 18. März 2009 13:31 schrieben Sie: > On Wed, Mar 18, 2009 at 04:36, Wolfgang Jeltsch wrote: > > Am Mittwoch, 18. März 2009 10:03 schrieb Benjamin L.Russell: > >> Just go through the list, choose your top favorite, and assign rank 1 > >> to it; > > &g

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Mittwoch, 18. März 2009 03:22 schrieb Robin Green: > I'm afraid it is entirely terminal-based (i.e. text only), so it doesn't > show the pictures. Hmm, this doesn’t help me since I’ve already written a terminal-based app. See attachement. However, no guarantees that this app works as intended.

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Dienstag, 17. März 2009 21:08 schrieb Robin Green: > However, I am now hacking together a quick-and-dirty utility for > ranking things which I will put on hackage. I'm not sure that anyone > other than myself will use it, but it's fun hacking it up. If you announce it on the mailing list, I mig

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Mittwoch, 18. März 2009 10:03 schrieb Benjamin L.Russell: > Just go through the list, choose your top favorite, and assign rank 1 > to it; Is rank 1 the best or the worst? I thought it would be the worst so I would probably have voted exactly the opposite way than I wanted to. :-( Best wish

Re: [Haskell-cafe] Re: Haskell Logo Voting has started!

Am Dienstag, 17. März 2009 16:55 schrieb Eelco Lempsink: > We'll see. Worst case: nobody votes (with 123 votes at this moment, I > don't think that will be the problem). Second worst case: most people > don't have/take the time to order a bit, so it turns into a majority > vote. Or there are man

Re: [Haskell-cafe] Type equality proof

Am Dienstag, 17. März 2009 21:51 schrieben Sie: > On Tue, Mar 17, 2009 at 6:14 AM, Wolfgang Jeltsch wrote: > > Am Dienstag, 17. März 2009 11:49 schrieb Yandex: > > > data (a :=: a') where > > > Refl :: a :=: a > > > Comm :: (a :=: a') -> (a

Re: [Haskell-cafe] Re: categories and monoids

Am Mittwoch, 18. März 2009 05:36 schrieb wren ng thornton: > Wolfgang Jeltsch wrote: > > Am Dienstag, 17. März 2009 10:54 schrieben Sie: > > > I'm reading the Barr/Wells slides at the moment, and they say the > > > following: > > > > > > "

[Haskell-cafe] Re: categories and monoids

Am Dienstag, 17. März 2009 18:43 schrieben Sie: > On Tue, Mar 17, 2009 at 5:06 AM, Wolfgang Jeltsch > > wrote: > > What is a “generalized monoid”? According to the grammatical construction > > (adjective plus noun), it should be a special kind of monoid > > There'

[Haskell-cafe] Re: categories and monoids

Am Dienstag, 17. März 2009 16:32 schrieben Sie: > On Tue, 2009-03-17 at 13:06 +0100, Wolfgang Jeltsch wrote: > > A category is not a “generalized monoid” but categories (as a concept) > > are a generalization of monoids. Each category is a monoid, but not the > > other wa

Re: [Haskell-cafe] Type equality proof

Am Dienstag, 17. März 2009 11:49 schrieb Yandex: > data (a :=: a') where > Refl :: a :=: a > Comm :: (a :=: a') -> (a' :=: a) > Trans :: (a :=: a') -> (a' :=: a'') -> (a :=: a'') I don’t think, Comm and Trans should go into the data type. They are not axioms but can be proven. Refl says tha

categories and monoids (was: Re: [Haskell-cafe] Design Patterns by Gamma or equivalent)

Am Dienstag, 17. März 2009 10:54 schrieben Sie: > Wolfgang Jeltsch writes: > > By the way, the documentation of Control.Category says that a category is > > a monoid (as far as I remember). This is wrong. Category laws correspond > > to monoid laws but monoid composition is

Re: [Haskell-cafe] Design Patterns by Gamma or equivalent

Am Dienstag, 17. März 2009 05:09 schrieb wren ng thornton: > a...@spamcop.net wrote: > > Or to put it another way, category theory is the pattern language of > > mathematics. > > Indeed. Though, IMO, there's a distinction between fairly banal things > (e.g. monoids), Monoids aren’t a concept of ca

Re: [Haskell-cafe] Natural Numbers: Best implementation?

Am Samstag, 14. März 2009 23:33 schrieben Sie: > On Fri, 13 Mar 2009, Wolfgang Jeltsch wrote: > > Class instances should satisfy certain laws. (Although these laws are > > often not stated explicitely, they are assumed to hold by users of the > > class and they should hold

Re: [Haskell-cafe] Microsoft PhD Scholarship at Strathclyde

Am Samstag, 14. März 2009 14:51 schrieb Conor McBride: > > Conor, is Epigram currently under development? > > We've even stopped working on the engine and started working on the chassis. > I'm in an intensive teaching block until the end of April, but from May it > becomes Priority. The "Reusabilit

Re: [Haskell-cafe] Microsoft PhD Scholarship at Strathclyde

Am Samstag, 14. März 2009 08:19 schrieb Peter Verswyvelen: > Well, in C++ one can already use the numerical values with templates for > achieving a lot of compile time computations. > > So I would be very happy to have this feature in Haskell. It might also be > good research towards full dependent

Re: [Haskell-cafe] Natural Numbers: Best implementation?

Am Freitag, 13. März 2009 09:21 schrieb Roman Cheplyaka: > * Alexander Dunlap [2009-03-12 20:01:57-0700] > > > Also, a lot of functions just take > > Integers so it would be more of a pain to use. > > AFAIK there are very few fuctions that take Integers. Many functions > take instances of Integral

Re: [Haskell-cafe] Natural Numbers: Best implementation?

Am Freitag, 13. März 2009 04:53 schrieb Brandon S. Allbery KF8NH: > On 2009 Mar 12, at 22:54, Mark Spezzano wrote: > > I was wondering what the best way to implement Natural number would > > be. Is there a package which already does this? > > type-level on Hackage. I think, the original poster wan

Re: [Haskell-cafe] Natural Numbers: Best implementation?

Am Freitag, 13. März 2009 04:01 schrieb Alexander Dunlap: > > 2.  Use the type > > > > data Natural = Zero | Succ !Natural > > […] > > In terms of speed, I think that [3] would be reasonably fast (unless > you do a ton of subtraction with bounds-checking) and [2] would > probably be quite slow, bec

Re: [Haskell-cafe] State monad is missing Applicative instance

Am Freitag, 13. März 2009 05:09 schrieb Denis Bueno: > This works because every monad induces an Applicative instance in a > way I've ingested just enough wine to forget. =] pure = return (<*>) = ap Best wishes, Wolfgang ___ Haskell-Cafe mailing list H

Re: [Haskell-cafe] Re: Against cuteness

Am Freitag, 13. März 2009 04:29 schrieb Benjamin L.Russell: > Consider the following logo: > > Silver red monad.png > http://commons.wikimedia.org/wiki/File:Silver_red_monad.png Can’t we choose something which is not connected to certain worldviews? Best wishes, Wolfgang _

Re: [Haskell-cafe] Re: Sugestion for a Haskell mascot

Am Donnerstag, 12. März 2009 22:00 schrieb Martijn van Steenbergen: > Deniz Dogan wrote: > > Then of course, > > there's the downside that there's no connection to the language itself > > in any way. > > I usually go for names that don't have to do anything with the > application itself: GroteTrap

Re: [Haskell-cafe] How to insert character key self in sourceView?

Maybe you should direct your question to the Gtk2Hs users mailing list . Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Sugestion for a Haskell mascot

Am Dienstag, 10. März 2009 00:59 schrieb Joe Fredette: > Hehe, I love it. Sloth is a synonym for Lazyness in English too, and > they're so freaking cute... :) Same in German: The german “Faultier” means “lazy animal”. Best wishes, Wolfgang ___ Haskell-

Re: [Haskell-cafe] FRP + physics / status of hpysics

Am Samstag, 7. März 2009 18:49 schrieb Roman Cheplyaka: > Great! I'll have more free time after March 15, and we can arrange an > IRC meeting to discuss this. I’d be happy if you would also invite me to this IRC meeting when it will finally happen. Best wishes, Wolfgang _

[Haskell-cafe] Re: [grapefruit] [reactive] FRP + physics / status of hpysics

Am Freitag, 6. März 2009 17:57 schrieb Wolfgang Jeltsch: > Am Freitag, 6. März 2009 17:51 schrieb Wolfgang Jeltsch: > > By the way, the adress of the Grapefruit mailing list is > > grapefr...@projects.haskell.org, not grapefr...@haskell.org. > > Oh, this is really strange: I a

[Haskell-cafe] Re: [reactive] FRP + physics / status of hpysics

Am Freitag, 6. März 2009 17:51 schrieb Wolfgang Jeltsch: > By the way, the adress of the Grapefruit mailing list is > grapefr...@projects.haskell.org, not grapefr...@haskell.org. Oh, this is really strange: I addressed my e-mail to grapefr...@projects.haskell.org but the version arriving

[Haskell-cafe] Re: [reactive] FRP + physics / status of hpysics

Am Freitag, 6. März 2009 14:34 schrieb Daniel Bünzli: > > without using recursive signal functions, > > If this is because there's this limitation in the frp system you use It is. > then better fix the system. The system is Grapefruit, by the way. And I’m its developer, by the way. :-) I have

Re: [Haskell-cafe] A foray into type-level programming, and getting stuck

Am Sonntag, 1. März 2009 22:10 schrieb Brian Bloniarz: > Hi George, > > Since none of the type metaprogramming specialists have answered you > on-list, I took a crack at this -- I think you can work around the issue by > avoiding overlapping instances entirely. I learned about this technique > from

Re: [Haskell-cafe] Re: base-4 + gtk2hs-0.10.0 licensing

Am Donnerstag, 26. Februar 2009 20:20 schrieb Achim Schneider: > Wolfgang Jeltsch wrote: > > Am Donnerstag, 26. Februar 2009 09:17 schrieb Ketil Malde: > > > Peter Hercek writes: > > > >> Relinking against newer Gtk2Hs versions might not work. > > > &g

Re: [Haskell-cafe] Re: base-4 + gtk2hs-0.10.0 licensing

Am Donnerstag, 26. Februar 2009 21:39 schrieb Peter Hercek: > The acceptable size of inlined fuctions for a C code is about 10 lines. > I did not read any info how it would be for Haskell. At least, GHC inlines very massively, to my knowledge. And I think you need this massive inlining for reason

Re: [Haskell-cafe] Re: base-4 + gtk2hs-0.10.0 licensing

Am Donnerstag, 26. Februar 2009 09:17 schrieb Ketil Malde: > Peter Hercek writes: > >> Relinking against newer Gtk2Hs versions might not work. > > You have the option of recompiling the new Gtk2Hs with the old GHC and > relinking, don't you? Relinking is technically not possible because of inlini

Re: [Haskell-cafe] Re: base-4 + gtk2hs-0.10.0 licensing

Am Mittwoch, 25. Februar 2009 23:38 schrieb Peter Hercek: > So my opinion (IAMNAL): > 1) source code under very limiting commercial license (just to allow > recompile with a newer LGPL lib and nothing else) is OK > 2) it is probable that only the *.o, *.hi files and a linking script are > OK too I

[Haskell-cafe] Grapefruit infrastructure

Hello, I just want to mention that the Grapefruit FRP library now has a mailing list and a Trac instance which contains a bug tracker. See: Please also note that the Grapefruit repositories have moved to code.haskell.org. Best wish

Re: [Haskell-cafe] subscription problems for projects.haskell.org mailing list

Am Mittwoch, 25. Februar 2009 17:15 schrieb Wolfgang Jeltsch: > Am Mittwoch, 25. Februar 2009 17:05 schrieb Wolfgang Jeltsch: > > Hello, > > > > I created a mailing list for Grapefruit on the Haskell Community Server > > (). If I try to subscribe to it, I > > rec

Re: [Haskell-cafe] subscription problems for projects.haskell.org mailing list

Am Mittwoch, 25. Februar 2009 17:05 schrieb Wolfgang Jeltsch: > Hello, > > I created a mailing list for Grapefruit on the Haskell Community Server > (). If I try to subscribe to it, I receive > a confirmation e-mail but my answers to this e-mail seem to get ignored. > Does a

[Haskell-cafe] subscription problems for projects.haskell.org mailing list

Hello, I created a mailing list for Grapefruit on the Haskell Community Server (). If I try to subscribe to it, I receive a confirmation e-mail but my answers to this e-mail seem to get ignored. Does anyone have an idea what’s wrong here? Best wishes, Wolfgang _

Re: [Haskell-cafe] base-4 + gtk2hs-0.10.0 licensing

Am Mittwoch, 25. Februar 2009 14:33 schrieb Duncan Coutts: > Note that some people will tell you that by a strict interpretation of > the LGPL that statically linked Haskell libs under that license are a > pain in the backside. When we decided on that license for gtk2hs that > was not our intention

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