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  • Solution2.html
    parent s = father s `mplus` mother s grandparent s = paternalGrandfather s `mplus`
    561 bytes (71 words) - 08:43, 9 April 2021
  • Solution3.html
    parent s = (maybeToList (mother s)) ++ (maybeToList (father s)) grandparent s = (maybeToList (paternalGrandfather s)) ++
    631 bytes (63 words) - 08:44, 9 April 2021
  • Stateful nondeterminism
    newtype SuperState s t a = SuperState { runSuperState :: (s -> t -> (t,[(a,s)])) } instance Monad (SuperState s t) where
    1 KB (169 words) - 05:31, 9 March 2021
  • Ko/adjoint
    newtype State s a = State { runState :: s -> (a, s) } * <hask>s -></hask>
    380 bytes (24 words) - 12:26, 6 December 2023
  • Solution4.html
    parent s = (toMonad (father s)) `mplus` (toMonad (mother s)) grandparent s = (toMonad (parentalGrandfather s)) `mplus`
    1 KB (151 words) - 08:45, 9 April 2021
  • Solution1.html
    maternalGrandfather s = return s >>= \ms ->
    1 KB (147 words) - 08:41, 9 April 2021
  • New monads/MonadSupply
    newtype SupplyT s m a = SupplyT (StateT [s] m a) newtype Supply s a = Supply (SupplyT s Identity a)
    1 KB (202 words) - 05:09, 4 April 2014
  • All About Monads/Solutions
    maternalGrandfather s = return s >>= \ms ->
    4 KB (454 words) - 02:33, 7 January 2022
  • Haskell Quiz/FizzBuzz/Solution Syzygies
    xor s t = if null s then t else s loop n s = cycle $ replicate (n-1) [] ++ [s]
    980 bytes (157 words) - 15:19, 6 February 2021
  • Unix tools/Date
    [s] <- getArgs putStrLn $ formatCalendarTime defaultTimeLocale s time
    543 bytes (78 words) - 15:19, 6 February 2021
  • Algorithmic information theory
    ...e writings on the relevance of algorithmic information theory, and Chaitin's thoughts of its relatedness to epistemology, biology. [[Chaitin's construction]].
    440 bytes (57 words) - 06:23, 4 February 2016
  • Binary IO
    It's very simple to use, and provides a highly efficient, pure interface * JeremyShaw's update of HalDaume's NewBinary package (Cabalized): http://www.n-heptane.com/nhlab/repos/NewBina
    2 KB (254 words) - 19:03, 23 October 2013
  • Literate programming/Bird conversion via sed
    s/^> // s/\(\n\)> /\1/g
    600 bytes (99 words) - 10:10, 7 November 2013
  • 99 questions/Solutions/33
    ...e the prelude function for computing gcd's along with a test of the result's equality to one.
    329 bytes (49 words) - 19:43, 18 January 2014
  • Diagrams/Dev/ReleaseAutomation
    .../github.com/bergey/diagrams-stow/blob/master/release/UpperBounds.hs Daniel's]) This page has ideas & requirements for building a less ad-hoc tool, whic Either Brent's tool or Daniel's (or both) performs each of the tasks listed above. In some cases the code
    2 KB (241 words) - 16:19, 22 June 2015
  • Alternatives and extensions for libraries
    ...n if it is (mostly) backward-compatible, and otherwise in the "alternative(s)" column. !Module(s)
    5 KB (633 words) - 15:16, 6 February 2021
  • Iteratee
    Page about the implementation of Oleg's Iteratee maintained by John Lato. * [http://okmij.org/ftp/Haskell/Iteratee Oleg's Original Implementation]
    2 KB (228 words) - 15:18, 6 February 2021
  • BayHac2017/Karya
    ...e hackathon on Friday and Saturday, and possibly Sunday afternoon if there's interest. To get sound you'll need VSTs, a VST host, and jack if it's linux. It's
    886 bytes (153 words) - 22:47, 5 April 2017
  • Web/Existing software
    ! Author(s) ! Maintainer(s)
    4 KB (491 words) - 10:14, 3 August 2015
  • Unsafe functions
    * <hask>unsafeInterleaveST :: ST s a -> ST s a</hask> * <hask>unsafeIOToST :: IO a -> ST s a</hask>
    1 KB (206 words) - 12:27, 8 June 2023
  • 99 questions/Solutions/49
    gray n = foldr (\s acc -> ("0" ++ s):("1" ++ s):acc) [] $ gray (n-1) gray' n = (gl . gr) [] where gl y = foldr (\s acc -> ('0':s):acc) y gp
    2 KB (298 words) - 03:02, 7 June 2021
  • 99 questions/Solutions/34
    (**) Calculate Euler's totient function phi(m). Euler's so-called totient function phi(m) is defined as the number of positive inte
    1 KB (224 words) - 19:44, 18 January 2014
  • Diagrams/GSoC
    ...nd raise the profile of the Haskell programming language. Most of all, it's fun---you get to tangibly experience your contributions in the form of beau
    1 KB (165 words) - 22:48, 5 March 2014
  • 99 questions/Solutions/94
    ...hs using graph canonization. It is somewhat of a slow solution, taking >10 s to run <hask>regular 6 3</hask>. [i : s | i <- n, s <- xs, i `notElem` s, asc (i : s)])
    2 KB (388 words) - 03:47, 10 January 2017
  • State Monad
    Because (State s) forms a monad, values can be combined with (>>=) or do{}. ...is a function from initial state s to final value a and final state s: (a,s). These are usually wrapped, but shown here unwrapped for simplicity.
    7 KB (1,055 words) - 15:06, 21 December 2018
  • Programming performance/Yasuo Common Lisp
    2007-03-01 closing=1403.17 change%=-0.25944346 cash=12389.992 assets=(#S(PURCHASE :AMOUNT 0.9840075 :ORIGINAL-PRICE 1399.04)) 2007-03-02 closing=1387.17 change%=-1.1402752 cash=12389.992 assets=(#S(PURCHASE :AMOUNT 0.9840075 :ORIGINAL-PRICE 1399.04))
    3 KB (309 words) - 16:40, 6 February 2015
  • Blog articles/Functional programming
    .../notes-on-haskell.blogspot.com/2007/02/whats-wrong-with-for-loop.html What's wrong with for loops] ...blogspot.com/2007/02/whats-wrong-with-for-loop-revisited.html More on what's wrong with for loops]
    2 KB (160 words) - 08:56, 16 April 2020
  • The Monad.Reader/Issue4
    This month's editorial is an encouragement to join the [http://www.haskell.org/mailman/l ...y, for example c2hs, Knit, and other projects require C parsers, but there's no common code base. Since parsers are one of the killer features of Haskel
    2 KB (241 words) - 22:48, 25 March 2017
  • Wadlers Law
    #redirect [[Wadler's Law]]
    61 bytes (8 words) - 12:43, 8 June 2023
  • Poor Man's Heredoc in Haskell
    #redirect [[Poor man's here document]]
    73 bytes (10 words) - 11:48, 8 June 2023
  • Knight's Trevails
    #REDIRECT [[Haskell Quiz/Knight's Travails]]
    79 bytes (10 words) - 06:56, 8 June 2023
  • Haskell Quiz/Knight's Trevails
    #redirect [[Haskell Quiz/Knight's Travails]]
    79 bytes (10 words) - 06:31, 8 June 2023
  • Xmonad/Config archive/Devin's Config.hs
    #redirect [[Xmonad/Config archive/twifkak's Config.hs]]
    90 bytes (12 words) - 12:56, 8 June 2023
  • Xmonad/Config archive/Gwern's Config.hs
    #redirect [[Xmonad/Config archive/Gwern's xmonad.hs]]
    88 bytes (12 words) - 13:01, 8 June 2023
  • Xmonad/Config archive/Lee Aylward's xmonad.hs
    #REDIRECT [[Xmonad/Config archive/leedo's xmonad.hs]]
    88 bytes (12 words) - 13:01, 8 June 2023
  • Don's Config.hs
    #redirect [[Xmonad/Config archive/Don's Config.hs]]
    86 bytes (12 words) - 04:31, 8 June 2023
  • Cabal/NewBuild
    ...mation about <code>cabal new-build</code>, the main entry point into Cabal's new Nix-style local builds facility. * Haskell at Work's [https://haskell-at-work.com/episodes/2018-05-13-introduction-to-cabal.html
    592 bytes (78 words) - 15:19, 6 February 2021
  • Haskell Platform
    == What's in the platform ==
    2 KB (260 words) - 13:28, 21 January 2020
  • Xmonad/Config archive/droundy's Config.hs
    #redirect [[Xmonad/Config archive/David Roundy's Config.hs]]
    95 bytes (13 words) - 13:00, 8 June 2023
  • LensBeginnersCheatsheet
    [http://hackage.haskell.org/package/lens Edward Kmett’s <code>lens</code> package]. ''“JQuery for Haskell values”.'' ...s.Setter] ||<code>over setter f s</code> ||<code>setter %~ f $ s</code> ||modify pure value
    5 KB (742 words) - 19:22, 22 May 2022
  • Xmonad/Config archive/Thomas ten Cate's monad.hs
    #redirect [[Xmonad/Config archive/Thomas ten Cate's xmonad.hs]]
    98 bytes (14 words) - 13:00, 8 June 2023
  • Recursion in a monad
    monadic <hask>do</hask>-block. Here's some quick examples: s <- foldM fn [] [1..n]
    986 bytes (142 words) - 15:18, 6 February 2021
  • Worker wrapper
    revWorker s [] = s revWorker s (x:xs) = revWorker (x:s) xs
    2 KB (333 words) - 12:44, 4 June 2018
  • HaskellImplementorsWorkshop/2013/Farmer
    ...being used in the wild, and discuss lessons learned about working with GHC's plugin mechanism. HERMIT is being used to optimize SYB traversals, to fuse Stream Fusion's concatMap combinator, and to implement staged compilation within GHC to gen
    1 KB (174 words) - 06:36, 16 September 2013
  • Xmonad/Config archive/gray hemp's .conky cpu
    echo ${cpu} | gdbar -s v -h 15 -sw 1 >> /tmp/.dzen2cpugraph echo ${cpu cpu1} | gdbar -s p -w 7 -nonl
    924 bytes (169 words) - 15:18, 6 February 2021
  • Xmonad/ghci
    ...in xmonad from ghci's main thread is another option, which requires xmonad's code to be modified slightly:
    1 KB (163 words) - 20:37, 8 February 2015
  • 99 questions/Solutions/82
    end s = (last s == n) && (length s /= 1)
    1 KB (153 words) - 06:29, 31 July 2021
  • Denotative
    where search :: STArray s Vertex Bool -> [Vertex] -> ST s [Tree Vertex]
    4 KB (488 words) - 04:24, 5 April 2024
  • BayHac2017/presentations/requested
    Here's how Haskellers responded to the following question in the Call for Particip * Any, but I'd especially like to help people improve docs if that's welcome.
    1 KB (145 words) - 18:33, 27 January 2017
  • MapReduce as a monad
    *All of the guts of MapReduce are hidden in the monad's <hask>bind</hask> function a -> ([(s,a)] -> [(s',b)])
    6 KB (1,053 words) - 03:27, 9 April 2021
  • Diagrams/GHC7.6
    ...to install diagrams of course cabal rejects the latest version. But here's where things go screwy: cabal then starts looking back in time to try to fi
    1 KB (207 words) - 15:18, 6 February 2021
  • The Monad.Reader/Issue2
    ...ages.inf.ed.ac.uk/wadler/index.html#links Links] language and Steele et al's [http://lambda-the-ultimate.org/node/view/673 Fortress] language are effort ...patibility, exploring dark corners of [[GHC]], [[domain specific language]]s, and the [[Foreign Function Interface]].
    2 KB (239 words) - 22:47, 25 March 2017
  • Sample Programs for Learning
    * [[Bresenham's line drawing algorithm]]
    226 bytes (25 words) - 01:10, 26 April 2021
  • QuickCheck / GADT
    ...sed algebraic datatype|GADTs]]. One solution is to use [[existential type]]s. The example here is a solution to one of the exercises in Fun with [[phant compress (RPair s t) (x,y) = compress s x ++ compress t y
    8 KB (1,072 words) - 18:32, 16 January 2017
  • Ireland HUG
    ...uncements regarding the provisional (as of Jan. 2012) Ireland Haskell User's Group will be posted here.
    247 bytes (34 words) - 15:19, 6 February 2021
  • Xmonad/Config archive/thoughtpolice's xmobarrc
    , Run Com "uname" ["-s","-r"] "" 36000 , Run Date "%a %b %_d %Y %H:%M:%S" "date" 10
    1,023 bytes (104 words) - 15:18, 6 February 2021
  • Concurrency demos/Zeta
    This little piece of code computes an approximation of Riemann's zeta function, balancing the work to be done between N threads. zetaRange s (x,y) = [ fromIntegral n ** (-s) | n <- [x..y] ]
    4 KB (555 words) - 10:58, 22 June 2021
  • 99 questions/Solutions/32
    ...ne the greatest common divisor of two positive integer numbers. Use Euclid's algorithm. ...for ours. The function gcd' is a straightforward implementation of Euler's algorithm, and myGCD is just a wrapper that makes sure the arguments are po
    777 bytes (117 words) - 19:42, 18 January 2014
  • Impredicative types
    ...ent and return a result of that type". All universal quantifiers ("for all"s) must appear at the beginning of a type. ...e, even inside normal datatypes like lists or <tt>Maybe</tt>. The GHC User's Guide gives the following example:
    2 KB (347 words) - 11:46, 4 February 2023
  • Simple Unix tools
    This is intended as a beginner's tutorial for learning Haskell from a "Let's just solve things already!" point of view. The examples should
    6 KB (842 words) - 05:27, 8 February 2016
  • Idiom brackets
    Since f is not a pure function, it's f :: x -> y -> m c. The correct form would be instance Idiomatic i f g => Idiomatic i (s -> f) (i s -> g) where
    2 KB (365 words) - 18:50, 19 September 2017
  • ListT done right alternative
    instance (MonadReader s m, Functor m) => MonadReader s (ListT m) where instance (MonadState s m, Functor m) => MonadState s (ListT m) where
    2 KB (402 words) - 06:31, 12 May 2015
  • BayHac2014/DenotationalDesign
    ...conal/talk-2014-bayhac-denotational-design/blob/master/README.md this talk's README on GitHub].
    298 bytes (41 words) - 05:35, 23 May 2014
  • Smart constructors
    This has a problem however, that the [[constructor]]s of type ''Resistor'' are data S a = S a
    9 KB (1,351 words) - 18:21, 6 June 2020
  • Roll your own IRC bot/Source
    ...e uncompilable). That page already has source for the bot anyway, so there's not much point in keeping this separate one.
    284 bytes (52 words) - 00:57, 17 June 2015
  • Case comprehensions
    but when it's used in case expressions: Could the GHC example benefit from some more list-comprehension syntax? Let's borrow a new reserved word:
    6 KB (743 words) - 02:12, 5 August 2021
  • Anonymous function
    ...ight look like this: <hask>\x -> x + 1</hask>. (That backslash is Haskell's way of expressing a &lambda; and is supposed to look like a Lambda.) .../ foldr</hask>. So if I wanted to add one to each element of a list, here's one way to do it (without anonymous functions):
    2 KB (296 words) - 06:56, 12 April 2021
  • 99 questions/Solutions/96
    identifier s = identifier' s 'l' identifier' (c:s) t = (match c t) && or [identifier' s b | (a, b) <- fsm, a == t]
    2 KB (346 words) - 03:47, 10 January 2017
  • Foldl as foldr alternative
    ...ve, however, is the ''wrong one'' for what we're trying to do here. So let's change the order of the arguments of the helper: Believe it or not, we're almost done! How is that? Let's parenthesize a bit for emphasis:
    5 KB (891 words) - 14:21, 3 January 2018
  • Let vs. Where
    f :: s -> (a,s) f :: State s a
    4 KB (716 words) - 07:41, 26 January 2019
  • Performance/Monads
    newtype DRMonad e s w a = DRMonad {runDRMonad :: s -> (Either e a,s,w)} instance (Monoid m, Error e) => Monad (DRMonad e s w) where
    6 KB (995 words) - 23:51, 16 April 2021
  • Extensible datatypes
    Here's a simple test for object orientation (for some reasonable definition): ...Haskell's <tt>[[Dynamic]]</tt>, where you only have to deal with <tt>B</tt>s that are instances of <tt>Typeable</tt>. But even with that, note that <tt>
    4 KB (587 words) - 11:16, 28 March 2018
  • ZuriHac2015/Projects
    ...GPU's. It's about unsupervised machine learning. Later: Convolutional RBM's. || Markus Liedl || BSD3 || https://github.com/haskell-munich/accelerate-rb
    3 KB (355 words) - 14:25, 30 May 2015
  • Applications and libraries/Hardware verification
    ...Moreover it is able to interface with third party EDA tools such as Altera's [http://www.model.com/ Modelsim] and [http://www.altera.com/products/softwa :David J. King and John O'Donnell's digital circuit simulator
    2 KB (333 words) - 11:47, 4 November 2014
  • GHC/QualifiedModuleExport
    The following is a list of previous documents and discussions about Haskell's module system: * Iavor S. Diatchki et al's formal specification of the Haskell 98 module system: http://purely-functio
    3 KB (368 words) - 22:21, 24 February 2016
  • GHC/TypeSigsAndAmbiguity
    ...fine, but alas not always. Perhaps this is a deficiency in GHC, but here's one way it can happen: What's going on? GHC knows, from the type signature that <tt>x::a</tt>. Then appl
    4 KB (716 words) - 11:30, 24 January 2016
  • Burton-style nondeterminism
    ...sing from the ordering of external events to a functional language. Burton's technique uses abstract values contained in an (theoretically) infinite str ...d with <code>contents</code> to retrieve the abstract <code>Decision</code>s for use by <code>choice</code>:
    2 KB (341 words) - 09:18, 22 February 2022
  • Hac φ/Attendees
    | Holiday Inn Express, Penn's Landing | Holiday Inn Express, Penn's Landing
    1 KB (190 words) - 14:59, 21 October 2016
  • 99 questions/Solutions/19
    ...convert the problem to the equivalent problem for n > 0 by adding the list's length to n. | otherwise = let (f,s) = splitAt n xs in s ++ f
    3 KB (474 words) - 20:35, 23 May 2021
  • Action
    * <code>ST s a</code>, the type of encapsulated-state actions. The condition that an action's effects only occur if performed prevents their use in otherwise-ordinary Ha
    3 KB (428 words) - 04:08, 12 April 2024
  • Type class
    For now we refer to Wikipedia's article about [http://en.wikipedia.org/wiki/Type_class type classes].
    322 bytes (46 words) - 10:06, 3 August 2015
  • Currying
    As an illustration, let's take the function <haskell>div :: Int -> Int -> Int -- which is actually But there's more going on here than immediately meets the untrained eye. It could be a
    4 KB (669 words) - 02:17, 3 November 2023
  • Humor/Dialogs
    Lazy Mom : Here's a credit card, Son. Just charge what you need. from myself. What's the use pretending I'm getting them from you?
    3 KB (445 words) - 15:19, 6 February 2021
  • GHC/Coercible
    toHTML s = MkHTML s fromHTML (MkHTML s) = s
    5 KB (887 words) - 06:53, 12 June 2023
  • Newtype
    ...hask> keyword with <hask>data</hask> and it'll still compile, indeed there's even a good chance your program will still work. The converse is not true, newtype State s a = State { runState :: s -> (s, a) }
    6 KB (1,007 words) - 15:57, 22 May 2016
  • Cont computations as question-answering boxes
    ...utation of type <code>Cont r s</code>. That's a bit brain-twisting, so let's think about how we might do it... ...is going to receive a question <code>q</code> about a value of type <code>s</code>, and has to answer it somehow.
    7 KB (1,253 words) - 23:34, 25 June 2021
  • Introduction to QuickCheck2
    Let's untangle that, and then test the referentially transparent isolation. Let's use QuickCheck. First we need an Arbitrary instance for
    8 KB (1,214 words) - 00:46, 23 October 2017
  • Darcs vs. Git
    = GHC's switch from darcs to git =
    571 bytes (77 words) - 18:50, 18 June 2014
  • 99 questions/Solutions/6
    Here's one to show it done in a fold just for the fun of it. Do note that it is le Here's one that does half as many compares:
    2 KB (320 words) - 00:08, 8 July 2019
  • Bowling
    Spare {frameScore=s} -> [[s-10]] Strike {frameScore=s,next=10} -> [[10],[s-20]]
    4 KB (555 words) - 15:19, 6 February 2021
  • Common Language Runtime
    ...S crew have made some good progress on creating a new target for GHC so it's doable at least. ...has proven that these can indeed be encoded with the current state of GHC's type features.
    2 KB (405 words) - 10:31, 9 February 2019
  • Difference list
    True, there's lot of right association, too, but bad enough. * Donald Bruce Stewart's [http://hackage.haskell.org/package/dlist difference list library]
    3 KB (421 words) - 16:40, 1 August 2018
  • 99 questions/Solutions/22
    Since there's already syntactic sugar for ranges, there's usually no reason to define a function like 'range' in Haskell. In fact, th
    1 KB (214 words) - 02:08, 5 April 2014
  • Diagrams/Dev/Migrate0.7
    ...ad use the <code>at</code> function to construct <code>Located Trail</code>s.
    2 KB (297 words) - 06:13, 3 August 2013
  • Syntactic sugar/Pros
    There's lot of advocacy at [[ThingsToAvoid/Discussion]] which may be moved to here.
    322 bytes (47 words) - 03:29, 14 August 2021
  • Stiri Ro/Haskell-2007
    8 iunie 2007 S-a primit de la domnul conf M. Gontineac stirea despre continuarea unor cerc ...subiecte de pe fiecare bilet s-au referit la Haskell. Toti studentii care s-au prezentat la examen au trecut cu succes examenul.
    3 KB (399 words) - 14:50, 18 February 2015
  • WxHaskell/Development/Debugging
    ...an error message and make a note of the exception code. Look at Microsoft's [https://msdn.microsoft.com/en-us/library/cc704588.aspx NTSTATUS values pag ...[https://www.gnu.org/software/gdb/ GNU debugger] to see the debug message(s).
    1 KB (221 words) - 23:10, 28 January 2016
  • Multi-parameter type class
    instance VarMonad (ST s) (STRef s) where ...
    1 KB (198 words) - 22:52, 21 July 2021
  • ThreadScope Tour/RTS
    s
    853 bytes (146 words) - 04:26, 26 April 2021
  • FFI Introduction
    Haskell's FFI is used to call functions from other languages (basically C at this poi ...] stuff. I could implement the whole tcgetattr / tcsetattr thing, but let's just turn ICANON on and off, so IO.getChar doesn't wait for a newline:
    2 KB (331 words) - 12:45, 17 February 2015
  • New monads/MonadExit
    instance MonadState s (ExitT e (State s)) where instance Monad m => MonadState s (ExitT e (StateT s m)) where
    4 KB (707 words) - 09:43, 9 December 2014
  • MonadFix
    ...ction in such as way as to feed the returned sum back into the parameter ''s'', and we will sneak the sum into the replaced tree! Example in ASCII art: 4 s
    10 KB (1,757 words) - 23:34, 24 July 2021
  • Web/Libraries/Templating
    ...ain goal is to provide you with fully type-safe templates. It uses Haskell's quasi-quoting facilities so that everything is checked at compile time. Unl | s.clover@gmail.com
    1 KB (193 words) - 04:57, 26 April 2021
  • Hdirect
    ...20100703013753/http://www.haskell.org/hdirect/user.html HaskellDirect user's manual] (HTML, in the Web Archive) :Describes HaskellDirect's features
    2 KB (253 words) - 18:19, 24 March 2015
  • Abstract data type
    Here's an example of a '''parameterized data type'''. isEmpty (StackImpl s) = null s
    5 KB (872 words) - 13:14, 2 September 2014
  • Quotes
    Oh like that's going to work. You'd be better off selling T-shirts that <oerjan> EvilTerran: no, it's for turning cotheorems into ffee.
    3 KB (561 words) - 02:55, 26 April 2021
  • Rubiks Cube
    == Rubik's Cube represented with faces == ...is a simple model for a [http://en.wikipedia.org/wiki/Rubik%27s_cube Rubik's Cube].
    8 KB (1,020 words) - 01:02, 23 September 2018
  • List comprehension
    [toUpper c | c <- s] where <hask>s :: String</hask> is a string such as <hask>"Hello"</hask>.
    5 KB (679 words) - 17:14, 4 February 2023
  • Gtk2Hs/Tutorials/ThreadedGUIs
    ...ere was little accurate info on how to do multithreaded GUI in gtk2hs. It's trivial. Events are run within GTK's own thread. There is no need for extra precautions when running event code.
    4 KB (613 words) - 21:06, 7 October 2014
  • GHC
    ...documentation below relates to ''using'' GHC. For documentation about GHC's internals and building GHC, head over to the [https://gitlab.haskell.org/gh ...rg/ghc/docs/latest/html/users_guide/index.html The User's Guide]: The User's Guide has all you need to know about using GHC: command line options, langu
    4 KB (626 words) - 14:08, 14 July 2020
  • ZuriHac2015/Projects/FRPGames
    ...gners to share assets. I tend to use SDL2 and 2D graphics, only because it's easier. You can also talk to the LambdaCube3D people and combine FRP and th ...ome to borrow (I only have one, you can bring your own if you want). There's online documentation and examples of how to use it.
    3 KB (578 words) - 15:24, 29 May 2015
  • 99 questions/Solutions/70
    return x = P $ \ s -> Just (x, s) P v >>= f = P $ \ s -> do
    7 KB (1,025 words) - 02:14, 23 July 2021
  • Enumerator and iteratee
    <hask>i</hask> is the type of the iteratee's input messages (or list elements) and <hask>o</hask> is a type of the outpu {- s = state -}
    6 KB (927 words) - 12:02, 19 April 2024
  • Frag
    Frag is described in Mun's 2005 undergraduate thesis, ...3D Games]. An AI system for Frag is described in Jayatheeban Soundararajan's 2007 undergrad thesis, also titled [http://www.cse.unsw.edu.au/~pls/thesis/
    3 KB (386 words) - 11:31, 5 May 2017
  • 99 questions/Solutions/85
    perm n = foldr (\x xs -> [i : s | i <- [1..n], s <- xs, i `notElem` s]) [[]] [1..n]
    2 KB (287 words) - 03:50, 10 January 2017
  • Wadler's Law
    Wadler's Law states that: Under these circumstances, Paul's ruling seems right: it is pointless
    4 KB (583 words) - 10:26, 26 December 2017
  • Disposing of dismissives
    * <code>freeSTRef :: STRef s a -> ST s ()</code> ...ssives like <code>hClose</code> and <code>finalizeForeignPtr</code>...here's an idea: adapt the techniques used for those other types and values, so the
    3 KB (431 words) - 04:31, 9 June 2022
  • Introduction to QuickCheck1
    Let's untangle that, and then test the referentially transparent isolation. Let's use QuickCheck. First we need an Arbitrary instance for
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  • Calitatea si inspectorul cozonacilor
    <!-- atravers: Perhaps there's an archived version you can use to restore it? (Remember to add the "Humor"
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  • Plainly partible
    * In Simon Peyton Jones's [[Books|The implementation of functional programming languages]] (section 9 ...with their concept implementation for a ''single-use'' variant of Hancock's unique-name supply, where each one can only be used once, if at all - from
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  • 99 questions/Solutions/37
    (**) Calculate Euler's totient function phi(m) (improved).
    373 bytes (58 words) - 19:46, 18 January 2014
  • Orphan instance
    ...you'd like to reuse that code for handling multiplication. But now, there's two definitions of Monoid Int! ...Revelation feature] of Modula-3 which causes similar problems like Haskell's type class instances
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  • Prelude extensions
    == Schönfinkel & Curry's amalgamation combinator, for Haskell == == Curry and Feys's paradoxical combinator, for Haskell ==
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  • Calling Haskell from C
    Here's how to do that. And that's it.
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  • Type variables instead of concrete types
    These functions can also be used for <hask>Integer</hask>s, Ok that's not possible, so just consider a <hask>State</hask> [[applicative functor]]
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  • Xmonad/Config archive/adamvo's xmobarrc
    , Run Com "uname" ["-s","-r"] "" 36000 , Run Date "%a %b %_d %Y %H:%M:%S" "date" 10
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  • GHC/Memory Management
    ...new value. But GHC is able to efficiently manage garbage collection, so it's not uncommon to produce 1gb of data per second (most part of which will be Haskell's computation model is very different from that of conventional mutable langu
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  • Humor
    Who says functional programmers never have any fun? Here's some of the * HaskellWiki's [http://www.haskell.org/haskellwiki/QuotesPage QuotesPage]. E.g. a quotatio
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  • Backpack
    ...arately-typecheckable packages on top of a weak module system like Haskell's. The design of Backpack is inspired by the MixML module calculus of Rossber ...U Backpack to Work: Towards Backpack in Practice] (video, NYC Haskell User's Group)
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  • MonadPlus reform proposal
    ...an an mzero, except the string argument; indeed, so far as I know <tt>fail s</tt> is just mzero for any MonadPlus. MonadPlus is also barely made use of ...e does satisfy Left Catch, but it seems almost like that's only because it's such a simple monad (holding only one value). It is a useful observation t
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  • Rational
    ...represent rational numbers exactly as the ratio of two <hask>Integer</hask>s. Applying <hask>toRational</hask> to an <hask>Integral</hask> number <hask
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  • WxHaskell/Download
    ...kell-bin-i386-mac2.8.4-ghc6.10.4-0.11.1.2-0.dmg] (MacOS X, Intel, (Leopard's) pre-installed wxWidgets, ghc 6.10.4, updated)<br /> ...kell-bin-i386-mac2.8.4-ghc6.10.3-0.11.1.2-0.dmg] (MacOS X, Intel, (Leopard's) pre-installed wxWidgets, ghc 6.10.3, updated)<br />
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  • Monk upgrade
    ...ell.org (aka haskell.galois.com; aka monk) is in need of an OS upgrade. It's currently running Debian ''sarge''; the upgrade will be to ''etch'', the cu ## Rollback plan(s)
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  • Xmonad/Config archive/Gwern's xmonad.hs
    ...xK_Print), unsafeSpawn "import -quality 90 -descend png:$HOME/xwd-$(date +%s)$$.png") ...[[:blank:]]\\+/ /g' > $TMP && screen -S 'irssi' -X readbuf $TMP && screen -S 'irssi' -X paste .;rm $TMP")
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  • 99 questions/Solutions/99
    together (w,s) = zip (siteCoords s) w solve' words (s:ss) = if null possWords
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  • O'Haskell
    * [http://okmij.org/ftp/Haskell/HList-ext.pdf Haskell's overlooked object system] (PDF) -- Object oriented concepts in pure Haskell
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  • Fizzbuzz
    There's also a page [[Haskell Quiz/FizzBuzz]] with another solution.
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  • Random shuffle
    (a,s') <- liftM (randomR lohi) (readSTRef g) writeSTRef g s'
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  • 99 questions/Solutions/26
    -- The implementation first checks if there's no more elements to select, -- if so, there's only one possible combination, the empty one,
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  • Xmonad/Notable changes since 0.7
    ...esktop Environment Integration|basic desktop integration]], including ewmh's for taskbars and panels, gap toggling, and sensible desktop default key reb ...tp://braincrater.wordpress.com/2008/08/28/announcing-xmonad-light/ shepheb's xmonad-light], your package manager, or
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  • 99 questions/Solutions/40
    (**) Goldbach's conjecture. Goldbach's conjecture says that every positive even number greater than 2 is the sum o
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  • Xmonad/Config archive/Template xmonad.hs (darcs)
    If you want a good configuration to start from, it's quite simple. ...a <code>composeAll</code> for the <code>manageHook</code>, or use Haskell's <code>do</code> notation for most other hooks.)
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  • Uniqueness annotations for types
    Usually, this is all that's required - rarely is there a subsequent need to annotate the types (fixed o Could a similar annotation be made available for ''uniqueness''? Let's borrow a small piece of [https://clean.cs.ru.nl/Clean Clean] syntax:
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  • IO at work
    * it's a special file which seems to change anyway (e.g. terminal devices, named p ...the I/O of an ''action'' (<code>IO</code> computation) outside of Haskell's expression evaluation by moving it into the surrounding runtime system. The
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  • Haskell/Lazy evaluation
    ...ty list, and any Int. The 'any Int' part is fine, so we need to know if it's passed an empty list. Answering that question forces one step in the evalua Now it's clear that <code>getIt</code> has not been passed an empty list, since the
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  • Bluetile
    time is the most limited resource among the majority of users. It's good if you can configure a software in every respect. It's better if you
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  • UnicodeByteString
    ...ing track of strings encoded as raw bytes stored in <hask>ByteString</hask>s. Using functions such as <hask>length</hask> on a Unicode string just work ...ns to encode and decode Unicode strings to and from <hask>ByteString</hask>s are provided together with <hask>Data.List</hask> like functions.
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  • Partible laws
    * <i>S</i>(<code>T</code>) is the set of <i>basic definitions</i> for <code>T</cod ...u :: T</code>) means <code>u</code> isn't used elsewhere by a member of <i>S</i>(<code>T</code>);
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  • 99 questions/Solutions/31
    isPrime n = all ((/=0).mod n) $ 2:3:[x + i | x <- [6,12..s], i <- [-1,1]] where s = floor $ sqrt $ fromIntegral n
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  • Type signatures as good style
    Using explicit [[type signature]]s is good style and [[GHC]] with option <code>-Wall</code> warns about missin runST :: (forall s . ST s a) -> a
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  • Bottom
    ...'&amp;perp;' and in LaTeX as '\bot' (within math mode). In plain ASCII, it's often written as the extremely ugly character sequence '<code>_|_</code>'.
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  • Real World Haskell
    it's for short, script-like programs or large and demanding applications. * Learn about Haskell's compiler, interpreter, values, simple functions, and types
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  • Gtk2Hs/Tutorials/TreeView
    let s = head (head sel) v <- Model.listStoreGetValue list s
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  • Monomorphism by annotation of type variables
    <i>For the moment, this proposal can be "emulated" using Haskell's type classes:</i> :instance Monomo (ST s a)
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  • Monad Transformers Tutorial
    Clearly we want something like Maybe's <hask>(>>=)</hask> here to catch the Nothing, but instead of Maybe values a ...its result in MaybeIO then we just have to use runMaybeIO there, and that's it. What happens if we now have some "print" in between?
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  • Programming performance/ArthurVanLeeuwen Haskell
    getDay s = getDay' $ words s
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  • Infix expressions
    For ease of reference, here's their elegant solution: For completeness, here's the `dual':
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  • Applications and libraries/Bioinformatics
    ...and alignment processing -- see [http://malde.org/~ketil/biohaskell/ Ketil's bioinformatics] [http://www.ii.uib.no/~ketil/bioinformatics/ pages], and [h * [http://www.techfak.uni-bielefeld.de/ags/pi/ Robert Giegerich's group (AGPI) at Bielefeld University]
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  • Threepenny-gui
    ...localhost. Latency would be too high to use it as a web app. That said, it's perfectly stuitable for implementing multi-user apps on a local network, se * ... not a JavaScript or HTML library. It's a GUI framework with a Haskell API and abstracts many aspects of the docume
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  • Base package
    *[[Arrow]]s *[[Functor]]s
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  • First-class module
    Mark Shields and Simon Peyton Jones's [https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.15.9282&rep=rep1 Because it has also [[Dependent type]]s, it can leverage them so that it is not forced to have a separate module la
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  • New monads/MonadRandom
    liftState :: (MonadState s m) => (s -> (a,s)) -> m a cumulative = scanl1 (\(x,q) (y,s) -> (y, s+q)) xs -- cumulative weights
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  • Diagrams/Dev/Fixpoint
    <blockquote>It's important that this is NOT a newtype, so we can freely use the ...nym means we lose the <code>Functor</code> instance! Also, in the end, it's probably better that users do not need to know the underlying implementatio
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  • Monomorphism
    As an example, <hask>map</hask> is polymorphic. It's type is simply
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  • Concurrency with oracles
    ...been research into ''deterministic'' concurrency (e.g. Eleni Spiliopoulou's work with the Bristol Haskell system as described in his thesis [https://ci ...ions from the interface for the corresponding abstract data type. After it's used, an oracle remains constant - reusing it will not provide a "different
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  • 99 questions/31 to 41
    Use [http://en.wikipedia.org/wiki/Euclidean_algorithm Euclid's algorithm]. <div style="border-bottom:1px solid #eee">(**) Calculate Euler's totient function phi(m). <span style="float:right"><small>[[99 questions/So
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  • Context alias
    ...d on [http://repetae.net/recent/out/classalias.html a page on John Meacham’s website]. data N = Z | S N
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  • Parsing a simple imperative language
    First let's specify the name of the module: ...; ''S2'' | ''( S )'' | if ''b'' then ''S1'' else ''S2'' | while ''b'' do ''S''
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  • Haskell Lisp
    Lispers who love Haskell can be heard saying that Haskell is Lisp's missing [http://en.wikipedia.org/wiki/M-expression M-Expression] implementa ...binaries were available for Sparc systems running SunOS 4.1.2 and Sparc 10's (sun4m) running 4.1.3. In the last release, the full functionality of X win
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  • Humor/Erlkönig
    It's Haskell with his child Hank; "My son, it's a wisp of the outside world." -
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  • Referential transparency
    In formalizing this idea for programming languages, Søndergaard and Sestoft[[#notes|[2]]] conclude by saying informally, ...ator is referentially transparent if it preserves applicability of Leibniz’s law, or substitutivity of identity: the principle that any subexpression ca
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  • IO in action
    * if a function's result changes, it is <b>only</b> because one or more of it's arguments has changed. * [[Merely monadic]] provides more information about Haskell's implementation of the monadic interface.
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  • Computer science
    Wikipedia's [http://en.wikipedia.org/wiki/Computer_science Computer science]. Wikipedia's [http://en.wikipedia.org/wiki/Computability_theory Computability theory].
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  • BayHac2014/Prolog
    Here's the code for the whole unification function; you can probably remember each ...ost of the Prolog code from my talk and some comments to help explain what's going on and give you a few exercises to better understand logic programmin
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  • Euler problems/1 to 10
    sumStep s n = s * sumOnetoN (n `div` s) ...ximum [x | y<-[100..999], z<-[y..999], let x=y*z, let s=show x, s==reverse s]
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  • How to profile a Haskell program
    details Jeff's use of profiling to solve the problems. ...ckled data structures via Data.Binary. The XML part is generated by HaXml's DtdToHaskell. On a 54M XML file, the thing swaps like crazy and takes seve
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  • Darcs repositories
    ...s love to read code. That's how we get a feel for what a language is. Here's a list of significant Haskell projects, by serious Haskell programmers, wit
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  • GHCi in colour
    The prompt can be colored by altering GHCi's <code>prompt</code> setting including [https://en.wikipedia.org/wiki/ANSI_e :set prompt "\ESC[34m\STX%s > \ESC[m\STX"
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  • Seq
    While its name might suggest otherwise, the <code>seq</code> function's purpose is to introduce ''strictness'' to a Haskell program. As indicated b ...guity is undesirable, which is why <code>pseq</code> also exists (but that's another story).
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  • WxHaskell/Contribute
    ...So, idea is that implementing com support on top of wxWidgets and Haskell's com support. ; Add new PowerShell's install and building script for Windows platform
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  • 99 questions/Solutions/90
    This is easy to understand, but it's also quite slow, as it generates and tests N^N possible N-queen configurati If a list already contains two queens in a line, there's no point in considering all the possible ways of adding more queens.
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  • Netwire
    Netwire's FRP framework is intended to be used for continuous applications. It repla Netwire's underlying abstraction is more powerful than the [http://conal.net/papers/i
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  • Mlist
    A value of type: MList IO a represents a list of a's whose evaluation continually requires executing actions in IO.
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  • GHC/CloudAndHPCHaskell
    == Peter Braam's thoughts about HPC & Cloud Compute Frameworks == ...became the software and communication "standard", and more recently GPGPU's (which have CUDA and OpenCL) and other accelerators (FPGA boards are seeing
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  • GHC/Common Error Messages
    ''Remark that [[GHC]]'s type errors are not always in the right places should go here''
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  • Unamb
    The agreement precondition ensures unamb's referential transparency. See also the [[lub]] package, which extends unamb's usefulness with non-flat types.
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  • Type arithmetic
    Somewhat related is Lennart Augustsson's tool Hallgren's 2001 paper
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  • Monad/ST
    ST s α ...they return a value of type <code>α</code>, and execute in "thread" <code>s</code>. All reference types are tagged with the thread, so that actions can
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  • Tiny Identifier Dictionary
    ! Identifier(s) ! Identifier(s)
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  • Euler problems/21 to 30
    ...#24 you don't need to generate all the lexicographic permutations by Knuth's method or any other. -- The "x"s are different numbers
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  • Multiplate
    ...write two functions: <code>multiplate</code> and <code>mkPlate</code>. Let's define each of these functions in turn. That's it. Now we are ready to use out generic library to process our mutually rec
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  • GHC/Typed holes
    ...mes, when writing programs, we tend to use lots of polymorphic types. That's good! We can reuse those pieces, thanks to the types. But it can be difficu ...even say <tt>undefined</tt> is just a really crappy, useless hole!) But it's special in that when GHC encounters a hole during compilation it will tell
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  • Yampa/reactimate
    ...e>) for the signal function. If the second component of <code>sense</code>'s return value is <code>Nothing</code> then the previous sample is used again ...put sample previously provided by <code>sense</code>. <code>actuate</code>'s job now is to process the output (e.g. render a collection of objects conta
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  • Diagrams/Dev
    ...ell-style-guide/blob/master/haskell-style.md Coding style guidelines]. It's not worth being super picky about these, but in general they are quite good * byorgey's time spent hacking on diagrams:
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  • Piq
    '''Note''': Piq is not ready for use yet. It's waiting for [[Reactive]] to get into better shape.
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  • Eta conversion
    ...tp://www.haskell.org/pipermail/haskell-cafe/2010-December/087782.html What's the motivation for η rules?]
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  • Converting numbers
    There are special cases for converting from <hask>Integer</hask>s: as well as for converting to <hask>Integer</hask>s:
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  • Upgrading from MTL 1 to MTL 2
    ...l.org/package/transformers transformers] package. You may wish to check it's the same, so you can just delete it. ...rwise you need to generalize your instance to <hask>StateT</hask>. If that's not possible, you may need to introduce a <hask>newtype</hask>.
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  • AI/Genetic programming/Evolutionary chess
    ...dea of what it would look like to apply genetic programming to chess. Here's a non-technical overview I wrote a few months ago, sketching out some of my .... To be a little more technical about it than I was in that overview, here's some more haskell-ish ideas.
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  • LUI
    * Adapter -- Allows adapting an existing widget's model (with a Data.Accessor), image or size. To implement focus delegation, widgets simply merge the child widget's event map with their own event map however they see fit.
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  • AI/Genetic programming/GPLib
    6) <s>Cabalized Library distribution.</s> a) Should probably be split according to which type system(s)
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  • Installers
    ...mon file types for .lhs/.hs files will be known, and that the Haskell tool's handlers ("Open in Tool", "Edit with Tool", ..) will be available via the r ...the existing ones. But users need a chance to say no, and if they do, that's it.
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  • Haskell in web browser/Calc example
    In conclusion, let's finally develop a program that does something useful. As another "classical ...ities. Another (<code>dispmb</code>) will be used to update the calculator's display element.
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  • Xmonad/Installing xmonad
    $ pacman -S xmonad-contrib # for the xmonad core and contrib packages $ pacman -S xmonad # for just the xmonad core package
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  • DDC/ReleaseNotes-Alpha1
    * It's a bit slooow.. ...to the type graph. We'd likely get a big improvement by only loading what's needed for each particular program. [http://code.google.com/p/disciple/issu
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  • Failure
    Terminology is a little confusing. There's a few different things floating around: But what is a failure? It's any time that something does not succeed. Of course, this depends on your d
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  • Scoped type variables
    Scoped Type Variables are an extension to Haskell's type system that allow free type variables to be re-used in the scope of a ida :: a -> a -- This refers to a in the function's type signature
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  • 99 questions/Solutions/91
    -- Knight's tours on an nxn board ending at the given square -- Closed knight's tours on an nxn board
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  • Diagrams/Install/Install-cairo
    ...y (along with development headers) installed through your operating system's package manager or otherwise. After that, it should ''ideally'' be enough t ...ere are instructions] for installing gtk2hs on Windows. Note that Haskell's gtk package requires gtk+-2.x, not 3.x. gtk+-2.24 is the most recent in th
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  • Parallel/Glossary
    : A locked mutable variable that can be shared across Haskell threads. MVar's can be full or empty. When reading an empty MVar, the reading thread block == S-Z ==
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  • GPipe/Tutorial
    Let's walk our way through an simple example as I explain how you work with these ...splayed in the window. But before I explain <hask>FrameBuffer</hask>s, let's jump to the start of the graphics pipeline instead.
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  • GetOpt
    toSettingsH (Filter s:fs) i = toSettingsH fs (i { filter = s }) toSettingsH (DateFormat s:fs) i = toSettingsH fs (i { dateFormat = i= })
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  • Foldable and Traversable
    ...ce.html Data.Sequence] is recommended as an efficient alternative to [list]s, But many interesting <hask>Foldable</hask>s are also <hask>Functor</hask>s.
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  • High-level option handling with GetOpt
    Sven Panne's GetOpt module does a fine job at parsing command line options. It but rather how supplied options influence program's behaviour, how error
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  • XMonadContribTour
    ...or new users, but applied to the XMonad Contrib. Mainly because I think it's very difficult for newcomers to discover what extra features XMonad provide ...b/XMonad-Hooks-DynamicLog.html#v%3AdynamicLogWithPP DynamicLogWithPP] that's a DynamicLog with a Pretty Printer. The DynamicLog contrib module ships wit
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  • Questions and answers
    ...y the <hask>Show</hask> class is so damn weird...) Even so, I wonder if it's more efficient to join strings or use real I/O... [[User:MathematicalOrchid ...hs has some image handling routines. for pure image format libraries there's unfortunately a little less :(
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  • Generalised algebraic datatype
    and, similarly, S is similar to the combinator data Term = K | S | Term :@ Term
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  • Gentoo
    ...(presumably), more flexible, and we're more likely to maintain it since it's in a language we prefer and are more used to.
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  • Monad Transformers
    .... The monad <code>State s a</code> is only a type synonym for <code>StateT s Identity a</code>. Thus both <code>State</code> and <code>StateT</code> can
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  • Generics
    ...s to polymorphism in Java, which is confusingly called "generics". Haskell's polymorphism can often be erased at compile-time, similar to Java where the ...lementation is necessary, similarly to <hask>Show</hask>, for instance. It's described in a [[GHC.Generics|separate wiki page]].
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  • Safely running untrusted Haskell code
    ...own monadic type that is a restricted subset of <code>IO</code>). But it's a lot more complicated than that... == Verifying safety: lambdabot's approach ==
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  • 99 questions/Solutions/39
    This is good for ''very narrow ranges'' as Q.31's <code>isPrime</code> tests numbers by ''trial division'' using (up to<math> ...http://www.haskell.org/haskellwiki/99_questions/Solutions/31 31st question's solution] (instead of the above sieve of Turner), adjusted to start its mul
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  • Safe Haskell
    * <s>magic</s> <s>omnimiscent</s> [http://www.softpanorama.org/SE/quotes.shtml idiot-proof]. ...unsafe feature, the purpose is to use it to implement a safe API - if that's the case, all you have to do is add <code>Trustworthy</code> to your langua
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  • Upgrading packages
    * [http://coldwa.st/e/blog/2017-09-09-Cabal-2-0.html What's new in Cabal/cabal-install 2.0 — improved new-build, Backpack, foreign li ...ownloads.haskell.org/~ghc/latest/docs/html/users_guide/index.html GHC User’s Guide]
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  • 99 questions/Solutions/23
    ...the target list length is > (orig list / 2). Here's another solution that's efficient in the other way (target < (orig list / 2)) by constructing an ac
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  • Shootout/Fannkuch
    Bertram's with a couple of refactors, a small let binding by Don, a new IO $ \s ->
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  • Ce optiuni se folosesc la compilarea din linie de comanda?
    % ghc-6.8.2 -S Foo.hc
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  • Diagrams/Dev/Transformations
    ...ctor with a <math>1</math> as its <math>n</math>th entry and <math>0</math>s everywhere else. For example, ...f the matrix, as I claimed. It's also not too hard to see that the matrix's action on any other vector is completely determined by linearity. Finally,
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  • Hac NYC/Talks
    ...and allows the calculation of quantities of physical interest. So far, it's mainly electromagnetic theory. | A brief account of a biologist's very pleasant experience with STM and Snap, for processing brain data and g
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  • Humor/Wanda
    In his "Filmgoer's Companion", Mr. Leslie Halliwell helpfully lists four of the cinema's greatest moments which you should get to see if at all
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  • Xmonad/Guided tour of the xmonad source/Core.hs
    These three record types make up the core of xmonad's state and configuration: * A value of type <hask>XState</hask> stores xmonad's mutable runtime state, consisting of the list of workspaces, a set of mappe
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  • Sound data structures
    ...hask>, [[Storable Vector|StorableVector.Lazy a]], <hask>(StateT s Maybe a, s)</hask> (like {{HackagePackage|id=stream-fusion}})
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  • Hack-Nix
    # The ways/base3.nix file let's you override and # In this example it's used to remove base >= 4 from the
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  • Functional programming/Old version
    move d0,s let s = z-(x+y)
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  • BayHac2017/CodeWorld
    ..., and casual games. In fact, I'm fairly comfortable saying that CodeWorld's collaboration API is the easiest way to build multi-player games in Haskell ...to jump in''' and work on more fundamental changes to CodeWorld, then here's a list of tasks of reasonable scope for a weekend.
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  • Yhc/Javascript/Programmers guide/EchoCPS2 demo source
    -- The s argument is the string to output, and the c argument is putLine s mbb c = getHTMLDocument $ \doc ->
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  • Floyd's cycle-finding algorithm
    ...ion of [http://en.wikipedia.org/wiki/Floyd's_cycle-finding_algorithm Floyd's cycle-finding algorithm] for finding cycles in lists.
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  • Functor-Applicative-Monad Proposal
    ...on] with [[Roles]]. Will "probably be fixed in the future", but for now it's off the table. ...k in 7.10.) To make 7.10 not complain about the then unrecognized flag, it's best to specify it in a CPP block,
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  • Blog articles/Comparisons
    ...details-on-f-computation-expressions-aka-monadic-or-workflow-syntax.aspxF#'s monadic syntax] * [http://www.acooke.org/cute/ErlangsSyn0.html Small comparison of Erlang's syntactic difficulties]
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  • GHC/Stand-alone deriving declarations
    ...-XUndecidableInstances</hask> to allow this instance declaration, but that's fair enough. GHC's "newtype deriving mechanism" (see [http://www.haskell.org/ghc/dist/current/
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  • Stiri Ro/Haskell-2013
    Aparut prin eforturile grupului Ro/Haskell volumul s-a dovedit o alegere inspirata fiind inca din primele luni de folos. S-a incheiat setul de laboratoare de programare functionala si grafica in HOp
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  • Xmonad/Screenshots
    Image:byorgey-config.png|Byorgey's dzen ...5073140/http://www.webframp.com/2009/01/06/xmonad-layout-gallery/ webframp's xmonad layout gallery] (archived; original page [http://www.webframp.com/20
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  • Space leak
    It's frustrating to study about leak when the examples given no longer leak for
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  • Benchmarks Game/Parallel/BinaryTrees
    -- more times the maximum residency)", as per GHC User's Guide: io s n t = printf "%s of depth %d\t check: %d\n" s n t
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  • Kind
    newtype StateT s m a :: * -> (* -> *) -> * -> * ...>. GHC introduces another inhabited kind, <TT>#</TT>, for [[unlifted type]]s.
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  • What a Monad is not
    ...pecific, it's IO that's impure. That makes the IO monad impure. But that's not a general property of monads - just IO. And even then, we can pretend t ...ly possible to abstract away explicit state passing by using a Monad, that's not what a monad is. Some examples for monads that are not about state: Ide
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  • Monoid
    ...instances are really more natural than the other, so we use the [[newtype]]s <tt>Sum n</tt> and <tt>Product n</tt> to distinguish between them: ...orementioned [[Foldable]], or the [[Writer monad]], or some [[Applicative]]s). But for a rather striking example of what Monoid can do alone, you can lo
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  • Applications and libraries/Database interfaces
    ...sely on Perl's DBI interface, though it has also been influenced by Python's DB-API v2, JDBC in Java, and HSQL in Haskell. Supports SQLite3, PostgreSQL, ...th the [http://www.haskell.org/haskellDB original version from Daan Leijen's] HaskellDB and the [https://github.com/m4dc4p/haskelldb HaskellDB more up-t
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  • 99 questions/90 to 94
    ...ant to work on one of these, put your name in the block so we know someone's working on it. Then, change n in your block to the appropriate problem numb <div style="border-bottom:1px solid #eee">(**) Knight's tour. <span style="float:right"><small>[[99 questions/Solutions/91|Solution
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  • GHC/AdvancedOverlap
    functional dependencies and overlapping instances, and that's what instance ShowPred Bool HTrue -- the same as Show's
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  • 99 questions/61 to 69
    % leaves(T,S) :- S is the list of all leaves of the binary tree T % internals(T,S) :- S is the list of internal nodes of the binary tree T.
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  • Performance/Data types
    ...space leak, because both components must be fully evaluated to <tt>Int</tt>s when the constructor is built. GHC's strictness analyser will detect that f is strict in its argument, and compi
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  • GHC under Wine
    [[GHC]] runs flawlessly under Wine. Here's a guide on how to get it working. First, get the latest stable version of Wine from your distribution's repository, or from http://www.winehq.com/site/download.
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  • A new list type
    ...information as they build it. If <hask>map</hask> is applied to a list who's size is known, the size of the result is known. (Interestingly, if it isn't Especially when it's infinite. See [[Things to avoid]] for why you should try to avoid calling <
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  • Internationalization of Haskell programs using gettext
    Let's start with an example. Suppose that we want to make the following program m printf (__ "Hello, %s, how are you?") name
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  • Xmonad/Guided tour of the xmonad source
    ...the [http://www.haskell.org/haddock/ Haddock]-generated documentation (it's all in the source code, of course, but may be nicer to read this way). XMo Without further ado, let's begin!
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  • CabalFind
    ...). This query currently returns 28 results, and all what is needed for one's package to appear there is to make the package directory (darcs repo) be vi querySearchEngine :: SearchEngine s => s -- search engine request
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  • Opting for oracles
    * A brief mention appears in Conor McBride's representation of general recursion for use with total functional languages ...Mikael Rittri and Dan Synek show how ''pseudodata'' can make Peter Hancock's <tt>name_supply</tt> viable for regular use. A small implementation by Iavo
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  • Type
    ...tor]]s, each of which has a list of [[type variable]]s or [[type constant]]s. At the end, there is an optional <code>deriving</code>. Let's look at some examples. The Haskell standard data type [[Maybe]] is typical
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  • Monads as containers
    -- take a container full of a's, to each, apply f, How about join? Well, let's have a look at the types.
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  • 99 questions/Solutions/46
    ...ld each logic function from scratch; they could be shortened using Haskell's builtin equivalents: The table function in Lisp supposedly uses Lisp's symbol handling to substitute variables on the fly in the expression. I cho
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  • Installing xmonad log applet
    ...table installing unsupported gnome components outside your package manager's control. Unfortunately, so far as I know they must be installed to location ...et on another host and simply install it on the small device, however that's outside the scope of this discussion.
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  • Curry-Howard-Lambek correspondence
    show (OK s) = s show (Warning s) = "Warning: " ++ s
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  • Budapest Hackathon 2016/Talks
    == András Kovács - A tour of GHC 8 features == ...codebases. Then we will look into our extensive use of QuickCheck, how it's used and what we learned.
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  • Applications and libraries/Generic programming/Lightweight
    the representation(s) data type(s) to be defined in the library and From what I've seen, Ralf's "Fun with phantom
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  • Trash/DDC/ClosureTyping
    ...the ''same'' <hask>Int</hask> every time we call it, but the type says it's supposed to be fresh! The problem here is that <hask>x</hask> was free in o ...e inferred types easier to read, DDC names the closure terms in a function's type after the free variables that gave rise to those terms. The user is fr
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  • Performance
    Moreover, it's often not clear if two programs which supposedly have the same functionalit ..., and multi-language memory management can be complex and error-prone. It's usually better to stick to Haskell if possible.
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  • PermissiveImportsProposal
    ...ven we've explicitly asked for the identifiers from specific modules there's no reason for the compiler to assume we might want them from the Prelude or ...with a large number of imports and contributors. At least with a pragma it's opt-in, and easy to change if a project later decides the redundancy is use
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  • Budapest Hackathon 2016/Projects
    ...rocessors and scratchpad memories. The backend currently supports Adapteva's Epiphany many-core accelerator chip. However, the implementation of the com ...started off as a copy/paste of the hspec-discover but now has come into it's own. It has the possibility to be a general purpose test runner with some w
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  • Constructor
    ...de</hask>. <hask>Tip</hask> is a constructor that groups no value, i.e, it's a nullary constructor. There is only one value, conveniently denoted <hask> ...hose data are its parameters. The first one has type <hask>a</hask>, so it's just a value of the parameter type <hask>a</hask>. This one is the value th
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  • Web/Frameworks/HAppS
    * By using HAppS's state management, you are committing yourself to keeping your entire state Prevayler' s architecture is illustrated in the diagram shown here. Prevayler [1] serves
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  • Catamorphisms
    data NatF a = S a | Z deriving (Eq,Show) fmap f (S z) = S (f z)
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  • Xmonad/Guided tour of the xmonad source/StackSet.hs
    of xmonad's state. Let's take a look at the definition of the ...epresent, so let's talk about them first, so we have a better idea of what's going on when they keep coming up later.
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  • Template haskell/Instance deriving example
    let s = nameBase nm in case dropWhile (/=':') s of
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  • Iteratee I/O
    As a beginner, you probably used Haskell's lazy I/O through the <code>System.IO</code> module. However, while it is go ...ell.org/package/liboleg liboleg] : An evolving collection of Oleg Kiselyov's Haskell modules (depends on the package unix and will therefore not compile
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  • Compatibility Modules
    parseInt s = case reads s of
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  • Research papers/Authors
    ==S==
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  • 99 questions/Solutions/63
    ...al nodes come first, the leaves come second, and empty successors (the nil's which are not really nodes!) come last.... ...every node X with address A the following property holds: The address of X's left and right successors are 2*A and 2*A+1, respectively, if they exist. T
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  • Arrow tutorial
    Let's define a really simple arrow type as an example, based on a function mappin Now let's define some operations that are generic to all arrow types:
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  • Merely monadic
    | an action, merely ''returning'' the argument's value. ...implementation calling <code>main</code>, according to the implementation's private definition of the abstract <code>IO</code> type.
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  • Attribute grammar
    Both Swiestra's article (mentioned above) and the Essential Haskell Compiler Project tool ( * (Reader, Writer, State) [[monad]]s,
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  • 99 questions/Solutions/50
    ...ruct a list hc(S,C) terms, where C is the Huffman code word for the symbol S. In our example, the result could be Hs = [hc(a,'0'), hc(b,'101'), hc(c,'10 Another short solution that's relatively easy to understand (I'll be back to comment later):
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  • ZuriHac2015/BBQ
    PS: There's gonna be a few welcome beers for the early birds ;-)
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  • 99 questions/Solutions/35
    Here's a concise alternative: And here's an improved version of the previous algorithm, which is slightly more verbo
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  • Chaitin's construction
    ...edia article on [http://en.wikipedia.org/wiki/Chaitin%27s_constant Chaitin's construction], referring to e.g. ...one for example in Section 4.1 of [https://tromp.github.io/cl/LC.pdf Tromp's paper].
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  • Extensible record
    ...cord_concatenation_for Typing record concatenation for free] on Erik Knoop's page ...s reading also paper on the [http://www.haskell.org/haskellDB/ Daan Leijen's original HaskellDB] page (see [http://www.haskell.org/haskellDB/doc.html Do
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  • BayHac2018/haddock
    ...markup types we don't have to pay the cost of 'String' and let GHC use it's efficient, internal string types.
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  • Functor
    .../hask>, can be made from <hask>f a</hask> by transforming all of its value(s), whilst leaving the structure of <hask>f</hask> itself unmodified.
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  • ZuriHac2014/Projects
    Revise the package's API and prepare the 2.0 version. ...o <hask>IntMap</hask>s, <hask>HashMap</hask>s, and general <hask>Map</hask>s.
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  • Dependent type
    <math>\forall x : S \Rightarrow T</math> <math>\mathbf G\;S\;(\lambda x . T)</math>
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  • AmeroHaskell
    Now a Haskell get together(s) anywhere in the USA with at least one in Portland, OR. ...- Raleigh, North Carolina. Will travel some, can stay somewhere overnight(s). Week of Oct 13-20 is not doable.
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  • The Fibonacci sequence
    [testBit n k | k <- let s = bitSize n in [s-1,s-2..0]] The Fibonacci numbers can be computed in constant time using Binet's formula.
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  • HacFreiburg2017
    HacFreiburg is Freiburg's Haskell Hackathon, where Haskell programmers from all around the world meet ...ell's power baffling and unapproachable. The talk will provide an outsider's view on a small but realistic project, highlight the pitfalls dealing with
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  • HaRe
    ...ojects into an AST with static semantics, and a token stream. Programatica's token stream contains layout and comments together with position informatio ...te monad. The first layer being Programatica's parser monad, and then HaRe's own state monad underneath. The reason for this is to plumb the token strea
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  • Haskell in 5 steps
    probably was "Hello, world!", so let's do that: Let's do something fun. In Haskell, your first true program is the
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  • Contstuff
    Let's have a look at a small example: ...putations carry state of a certain type and can access it at any time. It's called ''StateT'', just like in other transformer libraries, but this one h
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  • Monad laws
    It's now easy to see that monad composition is an associative operator with left If we re-write the laws using Haskell's <code>do</code>-notation:
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  • 99 questions/80 to 89
    ...ant to work on one of these, put your name in the block so we know someone's working on it. Then, change n in your block to the appropriate problem numb arc(s,u).
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  • Category theory/Functor
    * Wikipedia's [https://en.wikipedia.org/wiki/Functor Functor] article * nlab's [https://ncatlab.org/nlab/show/functor functor] and [https://ncatlab.org/nl
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  • Thunk
    -- if it's false, so is the result This function only evaluates the first parameter, because that's all that is needed. Even if the first parameter ''is'' true, you don't need
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  • Cabal/How to install a Cabal package
    There's an interesting Haskell package on [http://hackage.haskell.org/ Hackage] you
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  • Protect the community
    * [http://bikeshed.com/ Avoid bikesheds (related to Wadler's Law of Language Design)]
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  • Diagrams/Dev/Constraints
    ...c vs. R2Ish vs. R2Ish). The (R2Ish v) constraints change to (ScalarIsh (V s)) constraints. But writing them over and over again is boring, so we define * So now I'm thinking it's possible and useful to just always use V2. In particular, I can't write the
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  • Xmonad/Using xmonad in XFCE
    We're going to utilise Xfce's Session Manager to make sure that xfwm4 (Xfce's default WM) is no longer started. Preferably, it'd be nice if we could hav ...in some cases specific applications have their own settings directory), it's easier to backup the whole thing.
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  • Default method implementation
    It's always a design question, whether to provide default implementions of metho
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  • Gtk2Hs/Installation
    ...ll.org/platform/ the Haskell Platform]. You will need to add cabal-install's executable directory to your %PATH% (it will tell you which path to add in You must add cabal's executable directory to your $PATH next. By default, this directory is $HOM
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  • Emacs/Project navigation
    or just <code>M-x customize-group haskell</code> and it's in there.
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  • Applicative functor
    ...the above trick, but it is different from <hask>StateT s IO a == s -> IO (s, a)</hask>. The latter is more useful in some situations, and it is not a c
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  • Switching type classes at runtime
    Let's say we have a type class called "Throws":
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  • Introduction to Haskell IO/Actions
    Here's a simple example. Let's try to write a slightly more helper function that reads two lines
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  • Heterogenous collections
    If the number of [[type]]s to cover is fixed, then the problem can be you need to do) in the list. Beware: there is no safe downcasting (that's what
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  • 99 questions/46 to 50
    ...ruct a list hc(S,C) terms, where C is the Huffman code word for the symbol S. In our example, the result could be Hs = [hc(a,'0'), hc(b,'101'), hc(c,'10
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  • ZuriHac2016/Projects
    = <s>Discussion about Local Haskell Clubs</s> = sometimes to catch people's interest about Haskell. Maybe experienced
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  • Time
    ...re no leap seconds or timezones. You can compare two <tt>AbsoluteTime</tt>s directly to determine which one came first. You can reference time as far i ...uration of time measured in seconds. Subtracting two <tt>AbsoluteTime</tt>s with <tt>diffAbsoluteTime</tt> will produce a <tt>DiffTime</tt> and you can
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  • Haddock/Development ideas
    * There should be an annotation to include a function's entire definition in the documentation. This would be useful for functions
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  • Nokia Research Center Cambridge
    ...ion is for the Armo project, using Bluespec HDL to radically improve Nokia's ability to develop advanced SOCs and corresponding software for future mobi ...year old group of 16 researchers located in Cambridge, Massachusetts. NRCC's charter is to renew Nokia via open innovation, in particular via joint rese
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  • Mac OS X Common Installation Paths
    * Follows Apple's Guidelines for file system layout files. These are packaged using Apple's framework, versioning, and bundling
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  • Haskell a la carte
    ...Sorts not only integers but anything that can be compared. But granted, it's not in-place. ...rage again, this time with a type signature. Looks a bit strange, but that's the spicey ''currying''. In fact, <hask>average</hask> is a function that t
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  • Logic programming example
    Using the [[List Monad]] it's possible to rig up a basic logic program, where the bulk of the code simply == Verify the child's statement ==
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  • Blog articles/Parallel
    ...w.haskell.org/ghc/docs/latest/html/users_guide/lang-parallel.html GHC User's guide for parallel programming]
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  • Diagrams/Dev/Arrows
    ...ee</code>s) are created from the bottom (leaves) up, but <code>DTree</code>s transform) in its subtree. Brent's elegant solution was twofold:
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  • Web/Testing and Verification
    ...ds, libraries and applications for verifying the correctness of a web site's behaviour.
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  • The Monad.Reader/Issue3/Functional Programming vs Object Oriented Programming
    ...the pros and cons of functional or object-oriented programming. Rather, it's a guide for a new Haskell programmer coming from languages like Java, C#/.N ...mutable state then you can't ''guarantee'' referential transparency. That's the big deal with Haskell: no mutable state means you ''can'' guarantee ref
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  • SDL
    ld: symbol(s) not found ...haskell.org/package/Sprig Sprig], a foreign Binding to Jonny D's SDL Primitives Generator (SPriG) library
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  • Quasiquotation
    ...www.cs.tufts.edu/comp/150FP/archive/geoff-mainland/quasiquoting.pdf Why It's Nice to be Quoted: Quasiquoting for Haskell]. ...pecific syntax to construct fragments of their program. Along with Haskell's existing support for domain specific languages, you are now free to use new
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  • Existential type
    ...e variable rather than a type) but also isn't specified on the left (there's no 'b' in the left part). In Haskell98, you would have to write perimeter (Square s) = 4*s
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  • Hac Boston/Attendees
    | S FLUID
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  • Haiku
    Haskell's cryptic form<br> and so is Haiku's<br>
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  • Haskell Quiz/FizzBuzz
    ...his question. Solve it as you would under such circumstances for this week's Ruby Quiz."
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  • DeepArrow
    ...ronments for functional programming. I'd been wondering how to map a user's gestures into operations on a functional program. Lots of noodling led to ...skellwiki/phooey Phooey] is a functional GUI library that has much of Eros's GUI implementation techniques, but much more carefully structured than in t
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  • CouchDB
    ...wards replication. For more information read Anderson, Lehnardt and Slater's book "CouchDB - The definite guide" ([http://books.couchdb.org/relax/]). stripResult (Error s) = error $ "JSON error " ++ s
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  • Bresenham's line drawing algorithm
    And here is an implementation of generalized Bresenham's line drawing algorithm, in terms of balanced words: https://github.com/Lamb
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  • GeBoP
    ...lication features a brain viewer which enables you to explore the computer's internal game tree.
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  • Hac5/Attendees
    | Friend's place. | Friend's place.
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  • Tutorials/Programming Haskell/Introduction
    It's about time we got some job done in [[Haskell]], eh? Now, one of my Let's have at it!
    13 KB (1,817 words) - 17:53, 20 October 2016
  • New monads
    [[MonadLib]] is written by Iavor S. Diatchki. A refinement of MonadRandom to integrate RandomGen's split function.
    4 KB (648 words) - 09:43, 9 December 2014
  • ZuriHac2015/Projects/hackage-security
    ...t. It is based on The Update Framework (TUF) that has been inspired by tor's built-in software upgrade system. TUF is an implementation-independent spec
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  • Emacs/Inferior Haskell processes
    ...every one'' of these functions is already provided by inf-haskell.el! Here's a selection of the highlights: ...this by customising haskell-program-name) on your file. Don't worry if it's not an isolated module, GHCi will load all the modules it imports as normal
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  • AI
    ...programming language] like [http://www.eecs.harvard.edu/~avi/ Avi Pfeffer]'s [http://www.eecs.harvard.edu/~avi/IBAL/index.html IBAL] -- not only [http:/ I've proposed a machine learning library for this year's Google Summer of Code. [http://hackage.haskell.org/trac/summer-of-code/
    8 KB (1,161 words) - 08:26, 1 December 2018
  • Foldr Foldl Foldl'
    Let's start with the following: -- ... My stack overflows when there's a chain of around 500000 (+)'s !!!
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  • Modular Monadic Compilers for Programming Languages
    Primele luni ale anului 2011 s-au dovedit prolifice pentru realizatorii de compilatoare: type S = Int
    20 KB (2,558 words) - 22:39, 29 June 2021
  • Parallel/Digest
    ...rallel Haskell Digest is a newsletter aiming to show off all the work that's going on using parallelism and concurrency in the Haskell community.
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  • Tutorials/Programming Haskell/Argument handling
    Some clarifications on issues raised by yesterday's article. It's the 'id' function of the unix shell. BSD 'cat.c' is a [http://www.cse.unsw.
    25 KB (3,657 words) - 18:20, 12 September 2015
  • IO入門編
    ...tp://haskell.org/haskellwiki/IO_inside Haskell I/O inside: Down the Rabbit's Hole] を読んでみてください
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  • Xmonad/Using xmonad in Gnome/0.5
    Xmonad makes a great drop-in replacement for Gnome's default window manager (metacity) giving the user a slick tiling window man ...ager, it looks in the ~/.gnomerc file for the WINDOW_MANGER variable. Let's set that. My ~/.gnomerc file looks like this:
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  • Name clashes in record fields
    that retrieve the field's value from a particular record.
    1 KB (193 words) - 20:08, 23 July 2021
  • Category theory/Natural transformation
    ...hich forces us to convert our results to list format and exclude any Maybe's). (Perhaps, all this example is impractical and exaggerated, because in rea But if we want to do something similar with a ''parser'' on Maybe's to achieve a ''parser'' on list, then <hask>maybeToList</hask> is not enoug
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  • Evaluation order and state tokens
    Let's start off with a little quiz. What will be the output of running the follow The answer is: it's undefined. If you want to understand why, keep reading.
    21 KB (3,408 words) - 09:26, 9 September 2014
  • DDC/ReleaseNotes-Alpha1.1
    * It's a bit slooow.. ...to the type graph. We'd likely get a big improvement by only loading what's needed for each particular program. [http://code.google.com/p/disciple/issu
    4 KB (583 words) - 00:53, 9 April 2021
  • HaskellImplementorsWorkshop/2012
    ...Workshop/2012/Diatchki|Implementing Type-Level Literals in GHC]]''' (Iavor S. Diatchki) [http://www.haskell.org/wikiupload/1/11/Hiw2012-iavor-diatchki.p ...kellImplementorsWorkshop/2012/Stutterheim|Web browser programming with UHC's JavaScript backend]]''' (Atze Dijkstra) [http://www.haskell.org/wikiupload/
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  • POV-Ray SDL project
    However, all is not well in paradise. You see, while the SDL's programming capabilities are both simple and fairly flexible, what they are There's still a slight problem though. Some shapes have a 'radius'. However, spotli
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  • Applications and libraries/Robotics
    ...g/package/cv-combinators-0.1.2.3 cv-combinators] library that wraps OpenCV's high-level computer vision capabilities in a pure, functional interface.
    1 KB (178 words) - 12:02, 8 June 2023
  • Pattern guard
    Haskell 2010 changes the syntax for [[guard]]s by replacing the use of a single condition with a list of qualifiers. These From the GHC user's guide,
    1 KB (217 words) - 23:22, 24 July 2021
  • Windows
    * [http://www.pnotepad.org/ Programmer's Notepad] == Generating Dynamically Linked Libraries (DLL's) ==
    12 KB (1,886 words) - 19:30, 3 February 2021
  • Simon Has Fun
    An ongoing record of Simon's harassment is here: http://www.flickr.com/photos/97222587@N07/sets/72157635
    1 KB (192 words) - 23:05, 22 August 2013
  • Partibles for composing monads
    fail s = \ u -> let !_ = part u in error s
    4 KB (691 words) - 08:14, 12 June 2023
  • Performance/Strictness
    It's easy to accidentally write functions that aren't strict, though. Often a l ...er]]. However, the parameter <hask>acc</hask> isn't strict, because there's no guarantee that the caller will evaluate it. The compiler will use a ful
    7 KB (1,162 words) - 17:16, 8 June 2022
  • GADTs for dummies
    For a long time, I didn't understand what [[Generalised algebraic datatype]]s were or how they could be used. It almost seemed a conspiracy of silence &m Let's build a hypothetical Haskell extension that mimics, for type
    14 KB (2,322 words) - 13:55, 24 November 2023
  • MuniHac2016/Projects
    ...like points, sizes, polygons and most importantly matrices are there. It's also easy to bind missing datatypes. We use inline-c to inline C++ code in ghc-mod's codebase has been accumulating a lot of functionality over the years,
    11 KB (1,776 words) - 18:15, 3 September 2016
  • Applications and libraries/Network
    :Jun Mukai's search-based mail client, written in Haskell. ...n of [http://homepages.paradise.net.nz/warrickg/haskell/http/ Warrick Gray's original version].
    6 KB (929 words) - 18:17, 31 August 2016
  • Applications and libraries/Theorem provers
    ...fs and programs. Agda is also a functional language with [[Dependent type]]s. This language is very similar to Cayenne and Agda is intended to be a (alm ...und on [https://staff.fnwi.uva.nl/d.j.n.vaneijck2/index.html Jan van Eijck's page].
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  • HaskellImplementorsWorkshop/2013/Jones
    With a name that combines parts of "Ha"skell and "bit"s, Habit
    1 KB (189 words) - 06:37, 16 September 2013
  • Type SK
    possible spine shape up to 4 'App's deep. I could possibly do this more combinator. There are rules for reducing under both 2 and 3 'App's.
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  • Free structure
    * '''[[Monoid]]s''' ...cture; but we'll stick with sets now). What this means is that given <math>S</math>, we want to find some set <math>M</math>, together with appropriate
    13 KB (2,245 words) - 15:18, 6 February 2021
  • WxHaskell/Old wxHaskell news
    ...code.haskell.org/wxhaskell</code>). You can use previous darcs.haskell.org's Darcs repository, too.
    2 KB (259 words) - 21:40, 1 December 2015
  • Introduction to IO
    That's a mouthful, but once you see it in use, perhaps the idea will last action in the chain. So there's one more primitive,
    5 KB (958 words) - 15:20, 3 August 2022
  • Nonogram
    This is a solution done for simplicity rather than performance. It's SLOOOOW. If I were to check intermediate solutions against the blocks that type Row s = [s]
    17 KB (2,482 words) - 20:34, 8 June 2017
  • Links
    This page is obsolete. It's content has been replaced by: *<b>S:</b> [http://www.cs.chalmers.se/~andrei/ Andrei Sabelfeld], Chalmers Univer
    11 KB (1,759 words) - 09:41, 10 August 2022
  • Continuation
    ...rogram (for example, the call stack) at a certain point in time (Wikipedia's [http://en.wikipedia.org/wiki/Continuation Continuation]). ...lexical) <code>goto</code> instruction but a ''dynamic'' one (David Madore's [http://www.madore.org/~david/computers/callcc.html#sec_intro A page about
    10 KB (1,560 words) - 12:02, 15 April 2024
  • Toolmaking libraries
    ...ver and over, and which is affected by the existence of extensions. So let's define interfaces for libraries that make this easier and build some initia ...ped core around this language, after going over it with a comb to check it's adequately expressive?:
    5 KB (735 words) - 15:20, 6 February 2021
  • Salsa
    ...tp://code.haskell.org/Salsa/Samples/Conway Conway]: a simulator for Conway's Game of Life with a Windows Presentation Foundation GUI. (Requires .NET 3.0 | <pre-c>s.Length</pre-c>
    5 KB (685 words) - 07:56, 22 August 2016
  • Zipper
    ...ts transformed as we move from root to leaf. Recall our sample tree t. Let's name some of the relevant subtrees for brevity: There's a principled way to get the necessary types for contexts and the
    10 KB (1,623 words) - 21:10, 26 June 2023
  • Dealing with binary data
    Here's a very simple program which copies a file from standard input to Note that we are using strict bytestrings here. (It's quite common to import the
    17 KB (2,795 words) - 04:06, 16 June 2020
  • AtomicMemoryOps
    ...tionality for modifying popular data structures such as <hask>Vector</hask>s. More details about these problems can be found in a Haskell Implementor's workshop [http://www.youtube.com/watch?v=xiPrpWQN7m0 talk from 2012].
    5 KB (865 words) - 18:26, 21 November 2013
  • Introduction to Haskell IO
    ### show nested two-action do's ## nested do's
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  • HsLua
    What is Lua? It's a scripting language (like Perl) targeted to be literally 5 minutes. let's try:
    13 KB (2,016 words) - 18:34, 20 August 2017
  • Recursive function theory
    * Dr Matt Fairtlough's [http://web.archive.org/web/20060713051810/http://www.dcs.shef.ac.uk/~matt/ * Dr Matt Fairtlough's [http://web.archive.org/web/20060713051910/http://www.dcs.shef.ac.uk/~matt/
    13 KB (2,068 words) - 23:19, 3 June 2019
  • Euler problems/41 to 50
    problem_43 = sum . map l2n . map (\s -> head ([0..9] \\ s):s) let s = addZ 3 . reverse . explode $ m
    12 KB (1,626 words) - 05:45, 9 March 2021
  • Web/Comparison of Happstack, Snap and Yesod
    * [http://happstack.com/ Happstack's web site] is simple and clean. * [http://snapframework.com/ Snap's web site] is pretty and professionally designed.
    14 KB (1,908 words) - 02:23, 6 March 2017
  • Language Pragmas
    ...rs_guide/exts/pragmas.html#language-pragma chapter 6.20.1. of the GHC User's Guide].
    2 KB (248 words) - 14:43, 5 January 2024
  • Euler problems/181 to 190
    Here's another solution, and this one squeaks by in just under a minute on my mach import qualified Data.Set as S
    15 KB (2,018 words) - 01:29, 26 April 2021
  • Cabal
    *[http://hackage.haskell.org/ Hackage] - the Haskell community's public repository of cabal packages
    2 KB (244 words) - 12:34, 2 October 2020
  • The Monad.Reader/Issue2/Bzlib2Binding
    it is rather limited, but it's intended to answering some of the basic it's /System/Links/Headers/bzlib.h. It provides many of procedures of
    15 KB (2,511 words) - 06:03, 1 June 2022
  • Arrow
    ...ay be worth of solving a specific problem with arrows (instead of [[monad]]s) can be read in But Leijen's post is rather old (2000). Arrows are now significantly easier to understa
    11 KB (1,636 words) - 20:01, 13 May 2020
  • Live-Sequencer
    * Henning's Darcs repository with the cutting edge features:
    2 KB (314 words) - 09:50, 26 September 2018
  • Embedded domain specific language
    ...39639.html Designing DSL with explicit sharing (was: I love purity, but it's killing me)] ...askell/comments/2e8d53/whats_the_best_practice_for_building_a_dsl_in/ What's the best practice for building a DSL in haskell?], a discussion at Reddit
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  • GHC/As a library
    ...ell code dynamically in a GHCi-like manner. For this reason, a lot of GHC's features can be accessed by programs which import the <tt>ghc</tt> package. ...odule, but occasionally you may have to import other modules. See the GHC's [https://downloads.haskell.org/~ghc/latest/docs/html/libraries/ haddock doc
    9 KB (1,261 words) - 15:40, 22 December 2017
  • Parsing expressions and statements
    ...resentation and go straight to evaluation or code generation or... but let's fix just one goal here.) Here is an internal representation: ...s and returns a semicolon-separated sequence of one or more <hask>p</hask>'s.
    8 KB (1,033 words) - 02:43, 21 March 2018
  • Bravo
    ...are available on [http://hackage.haskell.org/package/Bravo Hackage]; there's no darcs repository for Bravo at the moment. ...ecessary. If the application is supposed to be released in binary form, it's not necessary to ship the template files with the application.
    9 KB (1,381 words) - 22:32, 29 June 2021
  • GHC/SuperClass
    There's an idiom that's briefly mentioned in the User Guide under [https://downloads.haskell.org/gh That's not wrong; but by talking about "class and instance contexts" in the same b
    14 KB (2,091 words) - 17:28, 4 February 2023
  • Infix operator
    ...ually, for a function taking more than two arguments, you can do it but it's not nearly as nice (note the need for extra parentheses):
    1 KB (159 words) - 23:45, 25 June 2021
  • Partial functions
    Usually if you have a partial function, it's because your types are incorrect and you should fix your types rather than
    1 KB (247 words) - 16:53, 15 November 2014
  • Web/Libraries/Formlets
    ...e, handle errors, abstract and are easy to combine into bigger forms. Here's an example: You can also have more advanced widgets, like a radio-choice, that's where you use enumRadio:
    8 KB (985 words) - 06:56, 16 September 2013
  • Data declaration with constraint
    You could use ghc's [https://wiki.haskell.org/GADTs_for_dummies Generalised Algebraic Data Stru
    2 KB (312 words) - 23:26, 19 September 2016
  • TypeDirectedNameResolution
    It's hard to gauge how much people like proposals like this, so let's try the experiment of collecting votes here: Names of people who think that on balance it's a bad idea
    7 KB (1,198 words) - 05:55, 10 December 2020
  • Cookbook/Dates And Time
    == Finding today's date ==
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  • Haskell Platform/FAQ
    ...mechanism, the platform process enforces standardisation on the candidate's base API before admission completes.
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  • Tutorials/Programming Haskell/String IO
    ...to speed by reading [[Tutorials/Programming Haskell/Introduction|yesterday's introductory article]]. [[Tutorials/Programming Haskell/Introduction|yesterday's article]].
    19 KB (3,139 words) - 04:08, 22 October 2021
  • Web/Framework Interfaces
    Hack is a simple interface for applications. Based on Ruby's Rack, it presents a very low barrier to entry. Unlike WAI, it uses lazy byt
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  • Bogre-Banana
    Programming in FRP consists of creating a network of "Behavior"s and "Event"s (although Events are more like event streams). A Behavior represents someth ...e-Banana. You can find more information about it at [[Reactive-banana | it's wiki page]]. It is highly recommended that you read the [[FRP_explanation_u
    12 KB (1,907 words) - 21:33, 19 September 2015
  • Haskell and mathematics
    * [http://www.cs.cmu.edu/~kw/pubs/conway.pdf Proving Conway's Lost Cosmological Theorem with Haskell]
    2 KB (242 words) - 05:23, 12 July 2021
  • Meet Bob The Monadic Lover
    Let's create a type for that: we'll call it "Lover", and a "Lover" friend's beloveds.
    28 KB (4,668 words) - 15:16, 6 February 2021
  • UrlDisp
    There's also an API which is believed to be more human-readable. ...t very interesting since one wants to interact with the outside world. Let's take a look at how to extend UrlDisp to handle database access.
    4 KB (592 words) - 21:17, 29 June 2021
  • Xmonad/Using xmonad in Gnome/0.6
    Xmonad makes an excellent drop-in replacement for Gnome's default window manager (metacity) giving you a slick tiling window manager. This should set up Xmonad to make space for Gnome's panel and status bar automatically. Note that this requires xmonad-contrib
    7 KB (1,095 words) - 15:16, 6 February 2021
  • Rank-N types
    ...The type is labeled "Rank-N" where N is the number of <hask>forall</hask>s which are nested and cannot be merged with a previous one. For example: -- | Append two 'ChurchList's. This runs in O(1) time. Note that
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  • How to get rid of IO
    Yes, each of those techniques produces more <code>IO</code> thingies. That's the real beauty of it: if you have a value that is dependent on the environ Alright, here's the short answer: '''You don't.'''
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  • Es/Librerias y Herramientas/Estructuras de Datos
    ...presentation into LaTeX (via Xy-pic) and into dot, the format for AT&amp;T's Graphviz tools. Since no horizontal sorting is done, the Xy-pic output is r :Iavor Diatchki's library of monad transformers for Haskell. It enables the quick constructio
    10 KB (1,459 words) - 19:29, 15 August 2019
  • Shootout/SumFile
    ...t on line length? What's the purpose of that if not to allow the use of C's getline() primitive (in both senses of the word)? And if we're picky, all import qualified Data.ByteString.Lazy.Char8 as S
    20 KB (3,239 words) - 02:07, 26 April 2021
  • Metaチュートリアル
    ...l/Publications/PaperStore/db-utwente-0000003696.pdf The Haskell Programmer's Guide to the IO Monad]
    5 KB (398 words) - 11:37, 22 October 2022
  • Weak head normal form
    ...ation just means substituting arguments for some of the lambda abstraction's variables, which always halts with the result a now-unapplied lambda abstra
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  • Applications and libraries/Linguistics
    Peter Ljunglöf's many [http://www.cse.chalmers.se/~peb/bibliography.html publications] on na [http://homepages.cwi.nl/~jve/index.html Jan van Eijck's page] contains a huge amount of materials on logic and language:
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  • Hackage
    '''Hackage''' is the Haskell community's central package archive. Package authors use it to publish their libraries
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  • Manatee
    Many people ask me "What's Manatee?", i think correct answer should be : ...not design for WM, it's design for OS, so don't compare it with XMonad, it's really different thing with XMonad. Please watch '''Window split''' feature
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  • Missing tutorials
    ...Mac, using Haskell to build those insanely great Mac applications. There's two ways you could go about it. One might be to build it as a Haskell-for-
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  • Mac OS X
    * Haskell binding to Apple's 2D animation and games framework SpriteKit. * install [http://www.macports.org MacPort]'s [http://trac.macports.org/browser/trunk/dports/lang/ghc/Portfile ghc] packa
    7 KB (1,042 words) - 15:32, 26 December 2022
  • Google summer of code
    Johan Tibell writes: I'm very happy with Adam's work strict Haskell. StrictData is already in HEAD and will be part of 8.0. Alex's excellent work is [https://github.com/Alllex/stm-data-collection here] and
    8 KB (1,152 words) - 13:09, 24 March 2018
  • Data.Semigroup
    ...noid</hask>. The <hask>Monoid</hask> typeclass however does not enforce it's instances to already be instances of <hask>Semigroup</hask></div> <div>The <hask>Semigroup</hask> is a particularly forgiving typeclass in it's requirements, and datatypes may have many instances of <hask>Semigroup</has
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  • BSD
    [http://wiki.freebsd.org/Haskell More information in the FreeBSD Wiki's Haskell page]
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  • How to work on lists
    :It's not in the book, but it's easy when you know how: ...in a list of actions) and then perform them using the trick above. But it's much simpler to do this:
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  • Non-strict semantics
    ...why people say that Haskell lets you write your own control structures. It's also one of the motivations behind Haskell being a [[pure]] language (thoug .../tt> processes the whole list, and then <tt>or</tt> finds any <tt>True</tt>s – but if the very first item of the list satisfies <tt>p</tt>, then you r
    9 KB (1,503 words) - 13:55, 15 December 2019
  • Links/O colectie de link-uri/iulie 2009
    Don's Papers - Thanx Don for all you had done for us !
    3 KB (432 words) - 05:52, 10 August 2022
  • Expanding type synonyms in error messages proposal
    ...-devs mailing list which suggests to add expansion of type-synonims in GHC's error-messages. Simon Peyton Jones suggested we should create a wiki-page f
    2 KB (215 words) - 09:14, 19 June 2015
  • HStringTemplate
    ...e [http://fmapfixreturn.wordpress.com/tag/hstringtemplate/ Sterling Clover's blog], and for downloads and API docs see [http://hackage.haskell.org/packa ...can be based around any 'Stringable' type, allowing you to use ByteString's or any other type if you write the Stringable instance. The template has a
    12 KB (1,726 words) - 15:16, 6 February 2021
  • HDBC-ODBC MS SQL under Linux
    If you are not using a DSN, it's critical to explicitly set the Port in the connection string
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  • 99 questions/Solutions
    ...for [[H-99: Ninety-Nine Haskell Problems]], with one page for each problem's solutions.
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  • Xmonad/Using xmonad in MATE
    print ("Current desktop %s is not supported." % current_desktop) print ("Killing pid %d (%s)" % (pid, pname))
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  • Euler problems/71 to 80
    [(n,sum [s * partitions ! p| (s,p) <- zip signs $ parts n])|
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  • Diagrams/Contributing
    It's recommended to use some sort of sandboxing tool while working on diagrams. For coding style, see Johan Tibell's [https://github.com/tibbe/haskell-style-guide/blob/master/haskell-style.md
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  • The JavaScript Problem
    Of all the alternatives, TypeScript's advantage is that it makes no changes to JavaScript. Existing JavaScript co ...p://www.haskell.org/haskellwiki/Yhc/Javascript an old wiki page] about Yhc's JavaScript support, but Yhc itself is a dead project.
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  • Short examples/BF interpreter
    This is [[User:SamB|SamB]]'s BF interpreter.
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  • Avoiding IO
    In some cases a state monad is simply not efficient enough. Let's say the state is an array and the update operations are modification of sin If the set of required effects is small, F. Warren Burton's ''pseudodata'' technique can be used to access them via abstract values in
    10 KB (1,634 words) - 22:52, 6 April 2022
  • OpenWRT
    ...de to integrate ghc into [https://wiki.openwrt.org/doc/howto/build OpenWRT's buildroot], the strategies here are pretty much synonymous with [https://gh it's also a good idea to de-select
    13 KB (1,967 words) - 16:07, 9 August 2016
  • Xmonad/Config archive/leedo's xmonad.hs
    xrandr -s 0
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  • Roll your own IRC bot
    network. So let's start by importing modules from the standard library and the ''network'' pa ...ails are important: the nick, the user name, and a channel to join. So let's send those.
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  • Strings
    There are two version of <hask>Text</hask>s: lazy and strict.
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  • Diagrams/Dev/Gradients
    (10:17) <Martingale> It's seems like we need information we don't yet have as we traverse the tree (10:43) <Martingale> that's for sure
    9 KB (1,383 words) - 16:48, 18 November 2013
  • Applications and libraries/Interfacing other languages
    Haskell's built-in features for interfacing to other languages are formally defined i ...002808/http://www.reid-consulting-uk.ltd.uk/docs/ffi.html Guide to Haskell's Foreign Function Interface]
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  • Blog articles/Mathematics
    ...://sigfpe.blogspot.com/2006/11/from-l-theorem-to-spreadsheet.html From Löb's Theorem to Spreadsheet Evaluation] ...an.blogspot.com/2007/07/peanos-axioms-iv-advanced-functions-and.html Peano's Axioms IV: Advanced Functions and Integers]
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  • Xmonad/xmonad development tutorial
    As a running example, let's suppose you want to develop an extension Receiving objects: 100% (13578/13578), 9.21 MiB | 2.00 MiB/s, done.
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  • Euler problems/11 to 20
    s <- senses, let is = take 4 $ iterate s i,
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  • GHC.Generics
    ...how you can use these types to represent others is to see an example. Let's represent the <hask>UserTree</hask> type shown before: M1 S NoSelector (
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  • Applications and libraries/Operating system
    :Kinetic is an operating system where the expressiveness of Haskell's type system guides the design of operating system features and facilities. ...re threading and exceptions are all realized via delimited [[continuation]]s.
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  • Unicode-symbols
    ...html C-x 8 RET]</tt> (<tt>ucs-insert</tt>), then type either the character's name or its hexadecimal code point. Use Agda's [http://agda.readthedocs.io/en/latest/tools/emacs-mode.html#unicode-input i
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  • FRP explanation using reactive-banana
    ...icit should provide the necessary background to understand reactive-banana's haddock comments. Spreadsheets are something we all (for certain values of we) know about. Let's talk about a typical, simplified, spreadsheet. We have a list of products t
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  • Prime numbers miscellaneous
    It's a pretty big wheel with a circumference of 210 and allows us to calculate t ...ing just <code>(p-1)/p</code>. See [[Prime_numbers#Euler.27s_Sieve | Euler's Sieve]], or the [[Research papers/Functional pearls|functional pearl]] titl
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  • Nitpicks
    ...s to the language. Even if they may be too onerous to change right now, it's possible that it would make sense to address them at some other time. * <hask>default</hask> is a useful name for a variable, but it's taken up as a keyword for the rarely used defaulting declaration. DefaultS
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  • Euler problems/31 to 40
    permutations n = take l $ map (read . take l) $ tails $ take (2*l -1) $ cycle s s = show n
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  • Yhc/Javascript/Programmers guide/Echo demo source
    -- Here are the functions to access web-browser's DOM structures. -- This function obtains reference to an object's method similarly
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  • Xmonad/Using xmonad in KDE
    Here's how to configure Xmonad to work with KDE. ...ttp://haskell.org/haskellwiki/Xmonad/Frequently_asked_questions XMonad FAQ's], [http://haskell.org/haskellwiki/Xmonad/General_xmonad.hs_config_tips XMon
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  • Video presentations
    Haskell is the world's leading purely functional programming language :Erik's 13 part lecture series on Haskell, using [http://www.amazon.com/Programming
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  • Emacs/Keybindings and simple usage
    Here's an example for <code>C-c C-=</code>. Put your cursor after <hask>myInt</has
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  • Lightweight concurrency
    ...libraries. For an earlier attempt at this problem, please look at Peng Li's paper [https://repository.upenn.edu/cgi/viewcontent.cgi?article=1391&contex -- For switch, target thread's status must be BlockedOn*. Otherwise,
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  • Internationalization of Haskell programs using Haskell data types
    render_en_US WhatsYourName = "What's your name?" render_pt_BR (Ihave_apples n) = "Tenho " ++ show n ++ " maçãs."
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  • Dmenu-4.0-xft.diff
    LDFLAGS = -s ${LIBS} + eprint("error, cannot allocate color '%s'\n", colstr);
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  • Game Development
    ....org/node/1277 The Next Mainstream Programming Languages: A Game Developer's Perspective] (PPT, PDF) presentation by Tim Sweeney .../feature/2985/postmortem_naughty_dogs_jak_and_.php Postmortem: Naughty Dog's Jak and Daxter: the Precursor Legacy]; an article about a game developed wi
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  • Pt/Haskell
    ...m superir, polimorfismo, classes tipadas e mônadicas. Compiladores Haskell são livremente disponíveis para as mais variadas plataformas. ;[[Image:Uma_Abordagem_Pratica.jpg|Cover]] Claudio Cesar de S and Marcio Ferreira da Silva: <em> Haskell: Uma Abordagem Prática</em>, [h
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  • BayHac2017
    <!-- Hide the "plz register" banner, it's basically too late now * 03:00pm [Upper room] Rúnar Bjarnason: [https://www.dropbox.com/s/lasx6zxkoe07jyq/AdjunctionsHaskell.pdf?dl=0 '''Adjunctions in Everyday Life
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  • Hac φ
    [http://www.spcapitaliq.com/ http://www.seas.upenn.edu/~antals/hac-phi/logos/S%26P%20Capital%20IQ%20@300.jpg]&nbsp; UPenn's admissions office has [http://www.admissions.upenn.edu/visit/directions-and
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  • Sandbox
    ...wiki's syntax highlight at least does not garble the source, unlike hpaste's highlight.
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  • Applications and libraries/Compiler tools
    ;[http://www.cse.unsw.edu.au/~chak/haskell/ctk/ Manuel Chakravarty's Compiler Toolkit] ...ribute Grammars Matter|Why Attribute Grammars Matter]]. Utrecht University's [https://web.archive.org/web/20170224115838/http://www.cs.uu.nl/wiki/HUT/At
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  • ListT done right
    instance (MonadReader s m, Functor m) => MonadReader s (ListT m) where instance (MonadState s m, Functor m) => MonadState s (ListT m) where
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  • Diagrams/Dev/AlignedCompose
    ...nal alignment/local origin has to be explicitly saved and restored if that's what you want. I'd like to have some combinators that automatically do thi
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  • ARM
    ...l-cafe/2013-February/106222.html almost was] but there were problems so it's not included. It will possibly be available in GHC 7.8.
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  • DDC/EffectSystem
    But wait, that's evil isn't it? ...if you actually had to write these extended types in regular programs. It's a good thing then that, for the most part, you can ignore the extended regi
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  • H-99: Ninety-Nine Haskell Problems
    ...ant to work on one of these, put your name in the block so we know someone's working on it. Then, change n in your block to the appropriate problem numb
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  • List of Projects that use Haskell
    People often ask, «Okay, Haskell looks like a fun language; but what's written in it?»
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  • GLFW
    GLFW.keyCallback $= \k s -> when (fromEnum k == fromEnum GLFW.ESC && s == GLFW.Press) $
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  • Research papers/Parallelism and concurrency
    ...Hammond K. Horiguchi S. Klusik U. Loogen R. Michaelson G.J. Pena R. Priebe S. Trinder P.W. Higher-order and Symbolic Computation 16(3) (2003). ...W. Trinder P.W. Hall C.V. Hammond K. Junaidu S.B. Morgan R.G. Peyton Jones S.L. Concurrency: Practice and Experience, 11(12) (December 1999), pp 701-75
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  • Syntactic sugar/Cons
    Haskell's basic syntax consists of function definition and function application. It's not amazing that Haskell provides a lot of syntactic sugar.
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  • Blow your mind
    ...of short, useful, cool, magical examples, which should incite the reader's curiosity and (hopefully) lead to a deeper understanding of advanced Haskel fix (\f l -> if null l then [] else let (s,e) = break (==' ') l in s:f (drop 1 e))
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  • Learn Haskell in 10 minutes
    ...ything is done with function calls), statically, implicitly typed ([[type]]s are checked by the compiler, but you don't have to declare them), lazy (not Calling [[function]]s is done by putting the arguments directly after the function. There are no
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  • Hoed
    ...formation during a program execution that shows unintended behaviour. Hoed's post-mortem algorithmic debugging view presents the user with questions abo
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  • Creating Debian packages from Cabal package
    ...in <tt>long_description</tt>. It's necessary due to the format of Debian's <tt>control</tt> file.)</li>
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  • Haste
    crash, and he was not able to recover it. That's the bindings haste2
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  • Diagrams/Dev/Migrate1.3
    <code>linear</code>’s functions are very similar to <code>vector-space</code>. The biggest differ This is the ''opposite'' way round to <code>vector-space</code>’s lerp.
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  • Yhc/Primitives
    ...result and forget about it. You can implement this as a 'fastccall' but it's quicker and standard FFI in any case.
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  • AngloHaskell/2008
    ...ink it should happen again, but this time at Imperial College, London. Who's up for it (add names further down)? This year it's being (un)organised by Matthew Sackman (matthew-_), Tristan Allwood (ToRA)
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  • Catch
    *[[Xmonad]]'s central StackSet.hs module has been checked repeatedly, as it has evolved.
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  • Xmonad/Using xmonad in Gnome
    Xmonad makes an excellent drop-in replacement for Gnome's default window manager (metacity) giving you a slick tiling window manager. ....desktop</code> file and running a full gnome session replacing only gnome's window manager. They tell gnome-session to use xmonad instead of metacity b
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  • OCaml
    OCaml's <tt>let</tt> is non-recursive by default, but has the form <tt>let rec</tt>
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  • Module signature
    There's a package on Hackage, you want to use it, but it has some signatures and yo Let's suppose you want to use the str-sig signature package. The general recipe i
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  • Rhine
    ...ymorphic in the clock. In that case, they are called <hask>Behaviour</hask>s, since they model the original FRP idea of a value (or function) varying wi ...tible clocks form the main high-level components, called <hask>Rhine</hask>s themselves.
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  • 99 questions/Solutions/16
    ...en concatenates the sublists to a result list (if not apparent: the author's a novice):
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  • GHC/GHCi
    ...[https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/ GHC User's Guide]. ...and snippets for use with the latest version of GHCi, beyond what the User's Guide covers. Please add to it!
    21 KB (3,021 words) - 12:03, 15 May 2020
  • Monomorphism restriction
    ...r that sharing f2 will have the same effect. If this seems arbitrary, that's because it is. It is difficult to design an objective rule which disallows ...riction is probably the most annoying and controversial feature of Haskell's type system.
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  • Tangible Value
    Now for the fun part. Let's combine the <hask>apples</hask> and <hask>bananas</hask> inputs and the <ha However, there's a much more elegant formulation, using <hask>uncurryA</hask> and <hask>$$</
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  • Applications and libraries/Data structures
    :*It's easy to migrate from standard Lists/Sets/Maps to the new package. The packa ...presentation into LaTeX (via Xy-pic) and into dot, the format for AT&amp;T's Graphviz tools. Since no horizontal sorting is done, the Xy-pic output is r
    17 KB (2,508 words) - 07:09, 8 June 2023
  • Xmonad/Notable changes since 0.12
    ...his bug fixed. With 0.13 release, you will want to modify your X11 session's xmonad startup to remove the <code>xmonad.state</code> file before launchin
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  • Applications and libraries/Compilers and interpreters
    implementing compilers and interpreters. Here's a selection of compilers ...mitted-choice constraint logic programming language, implemented using GHC's software transactional memory. According to the site referenced by the abo
    12 KB (1,707 words) - 07:27, 10 March 2020
  • Homework help
    ...teaching [[Questions and answers|beginners]] the language! However, there's an appropriate way and an inappropriate way to get help. If you have been your school's resources, then the Haskell community may be able to help you
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  • Boston Area Haskell Users' Group
    * To twist other people's arms to present
    2 KB (371 words) - 09:32, 12 September 2017
  • Diagrams/Dev/IRCHooks
    It's helpful to have repositories in the diagrams organization on github generat
    2 KB (329 words) - 13:42, 17 October 2014
  • Applications and libraries/Games
    ...me with SDL graphics and Kinect and Wiimote support. Written in FRP, there's a fork in Haskell for Android. ...example programs, please see [http://code.google.com/p/yogurt-mud/ Yogurt's home page].
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  • WebApplicationInterface
    Finally, it's not a goal of the interface to provide a nice API for writing web applicati , errors = \s -> hPutStr stderr s >> hFlush stderr
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  • OpenGL
    * [http://www.cin.ufpe.br/~haskell/hopengl/ Andre Furtado's nice tutorial] written in 2001 (bitrotted) ....haskell.org/package/vinyl-gl vinyl-gl]: Utilities for working with OpenGL's GLSL shading language and vinyl records
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  • Inlining and Specialisation
    The inliner's job is to replace a function with its definition. This removes one layer of # The function's (exact) definition is included in the interface file for the module.
    13 KB (2,038 words) - 10:49, 22 March 2017
  • The Monadic Way
    Wedler's is not explained. It's just magic.
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  • Software transactional memory
    ...011, there were more than 200 projects on Hackage with dependencies on GHC's STM implementation, including:
    3 KB (386 words) - 11:56, 15 March 2024
  • Implement a chat server
    runConn conn -- run our server's logic However, as we don't need the thread's id, we'll ignore the result.
    11 KB (1,739 words) - 04:19, 19 April 2024
  • Debugging
    ...rs-debuggers-and-over-interested-souls in the RTS section] of the GHC user's guide. s = M.lookup 4 m
    9 KB (1,453 words) - 19:18, 3 February 2021

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