Re: [Haskell-cafe] Using lenses

Lenses for nested sum types e.g. Either. On 03/10/2013 6:08 PM, "Simon Peyton-Jones" wrote: > (I sent this to ‘libraries’ but Kim-Ee suggested adding Café, where so > many smart people hang out.) > > ** ** > > Friends > > ** ** > > Some of you will know that I’ve promised to give a talk

Re: [Haskell-cafe] Traversals of monomorphic containers

These questions are exactly what Control.Lens answers. On 04/09/2013 12:50 PM, "Mario Blažević" wrote: > On 09/02/13 06:53, Nicolas Trangez wrote: > >> # Redirected to haskell-cafe >> >> On Sun, 2013-09-01 at 14:58 +0400, Artyom Kazak wrote: >> >>> Would this be an appropriate place to propose a

Re: [Haskell-cafe] mapFst and mapSnd

class BinaryFunctor f where bimap :: (a -> c) -> (b -> d) -> f a b -> f c d mapFst = (`bimap id`) mapSnd = bimap id On 31/05/2013 12:16 PM, "Shachaf Ben-Kiki" wrote: > On Thu, May 30, 2013 at 7:12 PM, Shachaf Ben-Kiki > wrote: > > One generalization of them is to lenses. For example `lens` h

[Haskell-cafe] LambdaJam 2013

et to the goal. So feel free to send me an email or I am on IRC (dibblego), lurking around the #haskell channel or privmsg if you like. Personally, I would love see more haskell submissions :) LambdaJam2013 call for papers: http://www.yowconference.com.au/lambdajam/Call.html -- Tony Morris

Re: [Haskell-cafe] CoArbitrary

ion that uses the argument?" -- fmap const -- type-checks, but ignores the argument, unlike e.g. QuickCheck which uses CoArbitrary to "perturb" that result with the argument. support libraries instance Functor Op where fmap f (DoubleOp g) = DoubleOp (f . g) fmap f

[Haskell-cafe] CoArbitrary

" away the argument. I hope I have phrased this in a way to make the point. I found it a bit difficult to articulate and I do wonder (hope!) that others encounter similar scenarios. Thanks for any tips! -- Tony Morris http://tmorris.net/ _

Re: [Haskell-cafe] Control.bimap?

_ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Segment Tree based Set

Yeah that looks useful indeed. I am surprised there isn't a DIET on hackage. On Tue, Oct 30, 2012 at 3:55 AM, Stephen Tetley wrote: > Are Martin Erwig's "diets" anything close? > > http://web.engr.oregonstate.edu/~erwig/diet/ > > On 29 October 2012 04:48, To

Re: [Haskell-cafe] Segment Tree based Set

18:36, Roman Cheplyaka wrote: > If you searched hackage, you'd find > http://hackage.haskell.org/package/SegmentTree > > Roman > > * Tony Morris [2012-10-29 15:38:07+1000] >> Er, oops. >> >> ...can be implemented as: >> \a rs -> let s = Set.fromList (rs

Re: [Haskell-cafe] Segment Tree based Set

Er, oops. ...can be implemented as: \a rs -> let s = Set.fromList (rs >>= \(a, b) -> [a..b]) in a `member` s Something like that! On Mon, Oct 29, 2012 at 2:48 PM, Tony Morris wrote: > Hi, > I was wondering if anyone knows of a package implementing a fast lookup > for

[Haskell-cafe] Segment Tree based Set

e seems like a more appropriate data structure to store the ranges. Does such a library exist? -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] foldr (.) id

ful when I need to > map a function over the list before composing. Does this function, or the > more general "foldr fmap id", defined in a library anywhere? I googled and > hoogled, but no luck so far. > > Thanks, > Greg > > > > __

Re: [Haskell-cafe] Why Kleisli composition is not in the Monad signature?

fe mailing list >> Haskell-Cafe@haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Flipping type constructors

ages/archive/TypeCompose/0.9.1/doc/html/src/Control-Compose.html#Flip I was wondering if there are any well-developed techniques to deal with this? Of course, I could just write my own Flip with the appropriate kinds and be done with it. Maybe there is a more suitable way? -- Tony Morris http:/

Re: [Haskell-cafe] Martin Odersky on "What's wrong with Monads"

t; > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Perth Functional Programmers meetup group launched

askell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Unit and pair

g list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe data-lens has something similar (Tensor): http://hackage.haskell.org/packages/archive/data-lens/2.10.0/doc/html/Control-Category-Product.html -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Haskell source AST zipper with state

Is there a library to traverse a source AST keeping state? -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Does somebody know about these functions?

On 01/03/12 14:40, wren ng thornton wrote: > Of course, you can simplify the implementation by: > > inter f xs = zipWith f xs (tail xs) inter f = zipWith f <*> tail -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing li

Re: [Haskell-cafe] Not an isomorphism, but what to call it?

> > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe It is not clear to me exactly what you are asking, so shot in the dark: injection or surjection? - -- Tony Morris http

Re: [Haskell-cafe] Functor0?

tinfo/haskell-cafe ? http://hackage.haskell.org/packages/archive/newtype/0.2/doc/html/Control-Newtype.html ? -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] strict, lazy, non-strict, eager

On 24/12/11 18:41, Gregory Crosswhite wrote: > On Dec 24, 2011, at 6:22 PM, Tony Morris wrote: > >> Wait what? >> >> I find it intriguing, helpful, provocative and potentially helpful toward >> the common goal of helping others. I am interested in further commenta

Re: [Haskell-cafe] strict, lazy, non-strict, eager

kell-cafe Wait what? I find it intriguing, helpful, provocative and potentially helpful toward the common goal of helping others. I am interested in further commentary. I'm not scared and you shouldn't be either. -- Tony Morris http://tmorris.net/ __

[Haskell-cafe] Lens with merge (Semigroup)

migroupT f a = SemigroupT (a -> a -> f a) -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Smarter do notation

ng, though. > > Any thoughts? > > Thanks, > Dan > > > > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe - -- Tony Morris http://tmo

Re: [Haskell-cafe] Pointed, but not Applicative

f) but not Applicative f => Applicative (StateT s f) - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJOWhtaAAoJEPxHMY3rBz0Pa3oIAMrqoyv4DW39VjIXwzV3/4Ir W5s0+fdo

Re: [Haskell-cafe] Simon PJ in Australia

html?eventId=3552 PS: we have a significant FP community here in Brisbane with nearly 250 members http://bfpg.org/ -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Data.Time

ong in assuming Data.Time is pretty useless? If I am right, and there is no alternative, I see no option but to take an excursion into writing my own. Ultimately, I am just trying to avoid this. Tips welcome. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.

[Haskell-cafe] Iteratee stack-consumption

sort of chunking the enumeratee or something? I was unable to find any good general hints in any of the hackage libraries. Thanks for any pointers. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http

Re: [Haskell-cafe] *GROUP HUG*

cidentally come to believe that. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] *GROUP HUG*

On 24/05/11 22:41, Johannes Waldmann wrote: > Then tell me, why does calculating the length of a (Haskell) > list has O(n) complexity. Infiniticity aside, tail would become O(n) if you store a length with each cons cell. -- Tony Morris http://tmorr

Re: [Haskell-cafe] *GROUP HUG*

> > Okay, I'm done now. :-) > > Cheers, > Greg > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___

Re: [Haskell-cafe] Robert Harper on monads and laziness

ing. http://github.com/scalaz/scalaz/ I have been teaching functional programming for quite a while, both in universities and outside of academia, and I am of the opinion that Haskell's suitability in first place has no close second place. I wonder why I am wrong, but this post (and previous) is ha

Re: [Haskell-cafe] Python is lazier than Haskell

overhead of laziness is taken into account. This is not what laziness gives us. Rather, it gives us terminating programs that would otherwise not terminate. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@hask

Re: [Haskell-cafe] How large is the Haskell community ?

niser of Brisbane Functional Programming Group with nearly 200 members. I have not seen anywhere near 50% post here. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFA

Re: [Haskell-cafe] Generalizing catMaybes

e many pointed functors that are not monads. The paper, Applicative Programming with Effects (McBride, Paterson) lists a couple. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozd

[Haskell-cafe] Generalizing catMaybes

omeone else's brain is molded into an appropriate shape to reveal an answer! - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk0n0lwACgkQmnpgrYe6r61

[Haskell-cafe] UTF-8 BOM

codeMarker then xs else s readBOMFile :: FilePath -> IO String readBOMFile p = dropBOM `fmap` readFile p -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] (Co/Contra)Functor and Comonad

obligation around, what could possibly be the > downside of adding a puny Cofunctor class to the base library? > > > > ___ Haskell-Cafe > mailing list Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell

[Haskell-cafe] dot-ghci files

have group write on that file for some reason. I'd appreciate some comments on this issue. Thanks. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Load testing

Does there exist a package for convenient load-testing against a website? e.g. making lots of HTTP requests against a server, including timing, and collecting the results? -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe

Re: [Haskell-cafe] category-extras clash with transformers

some packages failed to install: xmonad-contrib-0.9.1 failed during the building phase. The exception was: ExitFailure 1 - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozi

Re: [Haskell-cafe] category-extras clash with transformers

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 21/11/10 04:43, Ross Paterson wrote: > On Sat, Nov 20, 2010 at 10:58:44PM +1000, Tony Morris wrote: >> I have installed mtl-1.1.1.0 so that xmonad-contrib-0.9.1 would >> compile with GHC 6.12.1. >> http:

[Haskell-cafe] category-extras clash with transformers

packages failed to install: category-extras-0.53.5 failed during the building phase. The exception was: ExitFailure 1 - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

[Haskell-cafe] Non-hackage cabal source

download http://myhackage/packages/package/MyPackage-0.0.1.tar.gz : ErrorMisc "Unsucessful HTTP code: 404" Why is cabal even making this request? Why is it not making the request to http://myhackage/packages/MyPackage/0.0.1/MyPackage-0.0.1.tar.gz Thanks for any tips. -- Tony M

Re: [Haskell-cafe] Re: Re: A rant against the blurb on the Haskell front page

been coined to (and probably actually does) sound more commerce > friendly. To countermand such an effect, we can point out that most > libraries have non-copyleft licenses and that there are a number of > companies who have done and still do a lot to support and advance Haskell. > &

[Haskell-cafe] Network.HTTP, BasicAuth+Headers

uest equivalent to the following curl: curl --basic -u "user:pass" -H "Accept: application/xml" -H "Content-type: application/xml" "https://host/path"; It seems with Network.Browser I cannot send headers, but with Network.HTTP I cannot see how to send the Basi

Re: [Haskell-cafe] Re: Unwrapping newtypes

on how I could use that extension? > > Here is an example: {-# LANGUAGE GeneralizedNewtypeDeriving #-} class C a where c :: a -> Int data G = G instance C G where c _ = 7 newtype H = H G deriving C -- Tony Morris http://tmorris.net/ _

Re: [Haskell-cafe] Unwrapping newtypes

t > such a seemingly trivial problem seems so hard to do. > > I am wondering if I am missing something really, really obvious. > > Any suggestions? Or is there perhaps a more Haskelly way to place type > constraints on a more generic type? > > Kevin > __

Re: [Haskell-cafe] lambdacats

I wonder if the original site is recoverable from this, but I suspect there are some missing. On Fri, Aug 6, 2010 at 2:33 PM, Don Stewart wrote: > ivan.miljenovic: > > On 6 August 2010 14:12, Tony Morris wrote: > > > Hello, does anyone happen to have the lambdacats page ca

[Haskell-cafe] lambdacats

Hello, does anyone happen to have the lambdacats page cached? The domain ( arcanux.org) and server have disappeared and the wayback machine doesn't have the images. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell

Re: [Haskell-cafe] Monad transformers, design

gah you're right, @mtl had confuzzled me. Well that changes things then, thanks. Ross Paterson wrote: > On Sat, Jul 31, 2010 at 10:56:31PM +1000, Tony Morris wrote: > >> -- Suppose some data type >> newtype Inter a = Inter (Int -> a) >> >> -- and

[Haskell-cafe] Monad transformers, design

ather impractical instance (Copointed m, Integral a) => Ints (InterT m a) where ints (InterT a) = ints (copoint a) {- So it seems that for some type-classes it is possible to implement for both the data type and the transformer, but not all type-classes. Is there a general approach t

Re: [Haskell-cafe] Type-Level Programming

_ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Retrospective type-class extension

(f a) -> f a >> >> This would be a great idea, for the sake of logic, first (a monad >> which is not a functor doesn't make sense), and also to eliminate >> redudancy (fmap = liftM, ap = (<*>), etc.) >> >> 2010/5/20 Tony Morris > <mailto:tonymor...@

Re: [Haskell-cafe] Retrospective type-class extension

Ivan Miljenovic wrote: > On 20 May 2010 14:42, Tony Morris wrote: > >> We all know that "class (Functor f) => Monad f" is preferable but its >> absence is a historical mistake. We've all probably tried once: >> >> instance (Functor f) => M

[Haskell-cafe] Retrospective type-class extension

me to retrospectively apply such a notion? Ideally something like this would be handy if it could somehow be retrospectively applied: Monad <- Applicative <- Pointed <- Functor -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list

Re: [Haskell-cafe] What is the meaning of tilde ("~") symbol

there is one on > Hackage without any instances: > http://hackage.haskell.org/package/algebra > I do too. I also wish there was an associative: class F f where k :: f a -> f a -> f a without the zero component. -- Tony Morris http://tmorris.net/

[Haskell-cafe] Lazy language on JVM/CLR

as pure, lazy programming to run on the JVM in Java and Scala programming languages. I expect others have forethought and perhaps even experimented with such a language. Are there any dangers to be wary of that undo the entire endeavour? Thanks for any insights. -- Tony Morris http://tmorris.net

Re: [Haskell-cafe] Maybe, maybe not.

Ivan Miljenovic wrote: > 2010/1/27 Tony Morris : > >> It might be more obvious by giving: >> >> fromMaybe :: a -> (a -> x, x) -> x >> > > I actually found this more confusing, and am not sure of its validity: > should that be "May

Re: [Haskell-cafe] Maybe, maybe not.

ensionally) possible total functions with >>> that type, as far as I can see :) >>> >> Is the other one... const? >> > > As far as I can tell, yes. > > -- Tony Morris http://tmorris.net/ ___ Haskell

Re: [Haskell-cafe] Parse error

____ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Language simplicity

rise to me that C++ has the most > keywords. But then, if I were to add AMOS Professional, that had well > over 800 keywords at the last count... > > _______ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > Java has 53 reserved words. -

Re: [Haskell-cafe] ghc -e

Gwern Branwen wrote: > On Wed, Jan 6, 2010 at 7:23 PM, Tony Morris wrote: > >> ghc -e "import Control.Monad; forM [[1,2,3]] reverse" >> > > As of 6.10.2, the bug whereby the GHC API lets you use functions from > anywhere just by naming them (Java-st

[Haskell-cafe] ghc -e

Can I import a module when using ghc -e? e.g. ghc -e "import Control.Monad; forM [[1,2,3]] reverse" -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] (liftM join .) . mapM

Can (liftM join .) . mapM be improved? (Monad m) => (a -> m [b]) -> [a] -> m [b] -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Children elements with HXT

Adding (a_remove_whitespace,v_1) as a parser option when running solves it. Silly me. Tony Morris wrote: > I am trying to parse XML using HXT following > http://www.haskell.org/haskellwiki/HXT/Conversion_of_Haskell_data_from/to_XML > > Here is my XML file (way.xml): > > ver

[Haskell-cafe] Children elements with HXT

pElem "tag" (xpWrap (uncurry Tag, k &&& v) (xpPair (xpAttr "k" xpText) (xpAttr "v" xpText))) When I run, I get the following result: Main> run = runX (xunpickleDocument xpWay [] "way.xml") [Way {tags = []}] Why is the tags list empty ins

Re: [Haskell-cafe] Finding HP

then in my own humble opinion, snapping back with "\"Are you sure this isn't a user error?\" is not a particularly nice response" is not a particularly nice response. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Implicit newtype unwrapping

o ambiguous code? > > Thanks, > > Martijn. > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Tony Morris http://tmorris.net/ ___

Re: [Haskell-cafe] Working with multiple projects

I don't want to have to upload every time I make a minor change as I am working. Surely there is an easier way. Martijn van Steenbergen wrote: > Tony Morris wrote: >> I have two projects that I intend to put on hackage soon. One depends >> on the other. I have "cabaled&

[Haskell-cafe] Working with multiple projects

I have two projects that I intend to put on hackage soon. One depends on the other. I have "cabaled" both. I am wondering how others work with this kind of set up where changes are made to both libraries as they work. -- Tony Morris http://t

Re: [Haskell-cafe] Applicative but not Monad

g list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Cal, Clojure, Groovy, Haskell, OCaml, etc.

to understand stuff like that > might be to go thorugh it and convert it to use parens instead of $, > full application instead of ., and so on.) > > cjs > -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Comments requested: succ Java

John A. De Goes wrote: > write them yourself (at a cost of several to dozens of man years), Is that right? -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/hask

Re: [Haskell-cafe] Cal, Clojure, Groovy, Haskell, OCaml, etc.

> - a community > > - good library > > - a package manager > > Thoughts? > -- > Regards, > Casey > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mail

Re: [Haskell-cafe] Library function for map+append

t append > > but with less efficiency. Or am I wrong? > > Thanks > >Dusan > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > mapapp = ((++) .) . map

Re: [Haskell-cafe] Monoid wants a (++) equivalent

ding the obvious (<+) for > 'flip mappend' which is sometimes useful. > > > I actually think this proposal is pretty excellent. I happen to agree. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] List spine traversal

Is there a canonical function for traversing the spine of a list? I could use e.g. (seq . length) but this feels dirty, so I have foldl' (const . const $ ()) () which still doesn't feel right. What's the typical means of doing this? -- Tony Morris htt

Re: [Haskell-cafe] I need a hint in list processing

Just guessing. How do you know it's an accident? Richard O'Keefe wrote: > > On 15 Jun 2009, at 4:26 pm, Tony Morris wrote: > >> Prelude Data.List> nub . concat $ [[2, 3], [1, 2], [2, 3, 4], [1, 2, 3]] >> [2,3,1,4] > > In this particular case. But that&#

Re: [Haskell-cafe] I need a hint in list processing

to use it something like > > case all_choices sets of > [] -> there are no such choices > (first_choice:_) -> first_choice is one such choice > > For inputs like [[1,2],[2,1],[1]] there is of course no such > choice function. > > > _

Re: [Haskell-cafe] When folding is there a way to pick out the last point being processed?

> Regards, > Casey > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe

Re: [Haskell-cafe] Re: Non Empty List?

to the functions that operate on the > structure, ie. the lookups, inserts, delete etc. > > Günther > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > --

Re: [Haskell-cafe] instance Monad (Except err)

gt; is useful as an error monad: > > instance Monad (Except e) where > (OK x) >>= f = f x > Failed e >>= _ = Failed e > return = OK > > This obeys all the monad laws. > > Thanks, > > Neil. > _

Re: [Haskell-cafe] instance Monad (Except err)

_ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > I'm sure you could, but then ap /= (<*>). This seems related to a question that I once as

Re: [Haskell-cafe] Combining computations

l.org/mailman/listinfo/haskell-cafe > Hi Michael, You'll want the Data.Maybe.listToMaybe and Data.Maybe.maybeToList functions. -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] name for monad-like structure?

__ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > Are you sure it supports (>>) :: m a -> m b -> m b and not mplus :: m a -> m a -> m a ? -- Tony Morris http://tmorris.net/ __

Re: [Haskell-cafe] Getting the x out

________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > -- Tony Morris http://tmorris.net/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Monad explanation

ce if it ever > "gets in contact with" the top level it will be executed. But the > fact that IO types also behave as values makes Haskell a very > powerful imperative language. > > On Mon, Feb 9, 2009 at 11:14 AM, Tony Morris > wrote: You're right - my statement is ina

Re: [Haskell-cafe] Monad explanation

ng, but one > must remember that IO is abstract. > > -- Lennart > > On Mon, Feb 9, 2009 at 10:26 AM, Tony Morris > wrote: Gregg Reynolds wrote: >>>> The point being that the metalanguage commonly used to >>>> describe IO in Haskell contains a logical cont

Re: [Haskell-cafe] Monad explanation

has the type signature of a value. getChar has the signature RealWorld -> (RealWorld, Char) - -- Tony Morris http://tmorris.net/ * * Anteromedial Heterotopic Osseous Impingement Syndrome *

Re: [Haskell-cafe] Function const (Binding)

to get what I want) > > Thank you for your answers. > > Greetz TKM > > -- > > > ___ Haskell-Cafe > mailing list Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe - -- Tony

[Haskell-cafe] Applicative/Monad for Either

`mappend` e2)) (Z (Left e1)) <*> (Z (Right _)) = Z (Left e1) (Z (Right _)) <*> (Z (Left e2)) = Z (Left e2) (Z (Right f)) <*> (Z (Right a)) = Z (Right (f a)) instance (Monoid e) => Monad (Z e) where return = pure (Z e) >>= f = error "todo" -- ? - -

Re: [Haskell-cafe] Function composition

> > > -- > > _______ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe - -- Tony Morris ht

Re: [Haskell-cafe] About do notation.

gt; > I cannot figure out what is the (>>) and (>>=) way of this. > > Thanks. ___ > Haskell-Cafe mailing list Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > getArgs >>= (\a -&g

Re: [Haskell-cafe] Very silly

C++ templates, implemented via run-time >>> dictionaries and other modules may define new instances >>> > >> Personally, I have no clue how C++ templates work [yet]. (As in, I'm > > they are known as generics in java/c# > > Except they're not. Java Generics are so

Re: [Haskell-cafe] Having trouble with zip12..

@check \x -> (nub . nub) x == nub x -- is nub idempotent? OK, passed 500 tests. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIcS9LmnpgrYe6r60RAiDOAKCJlDaqNd5ssgxr

Re: [Haskell-cafe] zlib, missing zlib.h

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 apt-get install zlib1g-dev Tony Morris http://tmorris.net/ Real-world problems are simply degenerate cases of pure mathematical problems. Thomas Hartman wrote: > Tried to install > > http://hackage.haskell.org/cgi-bin/hackage-script

[Haskell-cafe] lambdabot on GHC 6.8.2

038) against GHC 6.8.2. Am I hitting this bug? If so, can I get around it to get a working lambdabot? Thanks for any tips. - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.

[Haskell-cafe] Test.QuickCheck.Gen

he error?), or if the current scenario is acceptable. I'm seeking comments about this, thanks! - -- Tony Morris http://tmorris.net/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIGjO6mnpgrYe6r60RAtohAK

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