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Why learn Haskell?

del.icio.us/haskell - Thu, 02/19/2015 - 8:55am
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Why learn Haskell?

del.icio.us/haskell - Thu, 02/19/2015 - 8:55am
Categories: Offsite Blogs

ghc and libgmp compiled separately

haskell-cafe - Thu, 02/19/2015 - 7:48am
i downloaded the centos65 binary of ghc only to find there was some sort of problem with libgmp on the system i am using. No problem i think, I'll just go grab the latest 4.x gmp compile it and use the --with-gmp flags to point ghc to my compiled version. didn't work. Don't have access to the machine from home, so i can't relay the precise error message (forgot to email it to myself), but it seems that the --with-gmp flags should have solved my problem (gmp compiled cleanly without any problems and put all the files in the right place). any obvious trickery involved when attempting something like this ? Thanks, Brian
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再帰ドリル

del.icio.us/haskell - Thu, 02/19/2015 - 7:11am
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Web development using Haskell

Haskell on Reddit - Thu, 02/19/2015 - 6:51am

Hi, I recently got into the Haskell world and I would like to use it for some web development. Ideally I would like to use a "minimalist" framework on the server-side combined with something like Angular on the client side. Can you share your experiences with web development using Haskell, as well as the frameworks/stacks you are using?

submitted by ruipfcosta
[link] [46 comments]
Categories: Incoming News

Spell checking Haskell comments

Haskell on Reddit - Thu, 02/19/2015 - 4:38am

Hi everyone,

I am wondering whether there is a utility for spell checking comments within Haskell files. Preferably runnable from the command line.

Failing that, I can use aspell with the documentation generated from haddock, however this isn't really ideal as it will change the HTML files generated, not the Haskell source.

I am using Ubuntu and am rather new to it, so there may be a general utility I should be using that perhaps someone can point me in the direction of?

submitted by AIburnett
[link] [6 comments]
Categories: Incoming News

Monads in a non Functional Programming language X Haskell.

Haskell on Reddit - Wed, 02/18/2015 - 11:18pm

Many sources claims that the 'fluent interface' ( From Martin Fowler) or 'method chaining' in Object Orientated languages are monads like JQuery and LINQ. Is that true ??

Those sources claims that JQuery is a monad:

The Sources below also claims that the Fluent Interface is a 'Monad' ( I don't know if it is really monads in C#) that encapsulates Null checking and Flow Control.

Fluent Interface:

By the definition of Monads they are:

  • A type that wraps a value or in other words, encapsulates an value

    M a

  • has an Method unit/ constructor

    unit :: a -> M a

  • has an Method bind ( >>= ) in Haskell

    bind :: M a -> ( a -> Mb) -> M b

I don't know how the Fluent Interface OO pattern fits the definition of Monads in FP.

Here one example from: http://channel9.msdn.com/coding4fun/blog/Being-Fluent-Fluid-and-Functional-with-Monadsnet

http://files.channel9.msdn.com/wlwimages/ae054c0b4d7b402ab1239e6800c0220f/image%5B2%5D-175.png

submitted by eniacsparc2xyz
[link] [19 comments]
Categories: Incoming News

Testing polymorphic properties with QuickCheck

haskell-cafe - Wed, 02/18/2015 - 10:41pm
Hi, I'd like to use QuickCheck to test polymorphic properties and I'm wondering if there's any community consenus on how to do this while avoiding creating large amounts of boilerplate test code. As an example, suppose I have this simple simplistic Monoid typeclass: class Monoid a where zero :: a (|+|) :: a -> a -> a And suppose I make these types Monoid instances: instance Monoid Integer where zero = 0 (|+|) = (+) instance Monoid Rational where zero = 0 (|+|) = (+) instance (Monoid a, Monoid b) => Monoid (a, b) where zero = (zero, zero) (|+|) (x, y) (u, v) = (x |+| u, y |+| v) Using QuickCheck and the Tasty test framework I'd like to test the Monoid laws across the relevant types (I'm only showing one part of one law here) as QuickCheck properties: prop_left_add_id :: (Eq a, Monoid a) => a -> Bool prop_left_add_id x = zero |+| x == x monoid_suite :: TestTree monoid_suite = testGroup "monoid" [ testProperty "left additive identity (Integer)" (prop_left_add_id :: Integer
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Which JetBrains plugin is considered the best at this time?

Haskell on Reddit - Wed, 02/18/2015 - 9:49pm

I see 4 Haskell plugins listed in the JetBrains plugin respository. I'm a Haskell noob so I wouldn't know which features to place more weight on - could someone using Haskell with a JetBrains IDE advise on which one works best?

submitted by asampaleanu
[link] [10 comments]
Categories: Incoming News

Let's teach GHC idiom brackets!

haskell-cafe - Wed, 02/18/2015 - 9:46pm
Hi friends, Last night I was having a good natter with Chris Done, and the topic of idiom brackets came up. Specifically, Chris' hindent and structured-haskell-mode tools have both recently become aware of the quasiquoter in applicative-quoters <http://hackage.haskell.org/package/applicative-quoters> - allowing one to write ordinary Haskell code but have it formatted/edited as if it wasn't even inside a quasiquoter. However, it's a shame that Chris has to now be aware of this specific quasiquoter just to get his tools to work properly. Furthermore, it's a shame that *everyone* has to do the same whenever they want to manipulate Haskell code. That said, idiom brackets - at least to me - appears to be a very desirable syntax extension. A recent desire for this came to me while working with reactive-banana. As almost everything "interesting" is even an Event or a Behavior, there tends to be a lot of assembling programs with applicative syntax. Another obvious example is when using parser combinators. Therefo
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Primitive Haskell | FP Complete

del.icio.us/haskell - Wed, 02/18/2015 - 5:45pm
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ApplicativeDo

glasgow-user - Wed, 02/18/2015 - 5:34pm
There is a library for TH: http://hackage.haskell.org/package/applicative-quoters-0.1.0.8 (broken at the moment) There is a proposal at: https://ghc.haskell.org/trac/ghc/wiki/ApplicativeDo Now with AMP, is this worth revisiting? Why or why not? -Tom _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users< at >haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/glasgow-haskell-users
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fpco/mezzohaskell

del.icio.us/haskell - Wed, 02/18/2015 - 4:34pm
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Current best way to learn haskell and functional programming?

Haskell on Reddit - Wed, 02/18/2015 - 9:40am

There's the links on the sidebar and these: http://yannesposito.com/Scratch/en/blog/Haskell-the-Hard-Way/ http://upload.wikimedia.org/wikipedia/commons/a/aa/Write_Yourself_a_Scheme_in_48_Hours.pdf http://dev.stephendiehl.com/fun/ So many to choose from, its a bit overwhelming. Any opinions on a good tutorial that's rigorous/not watered down, has theory etc? More CLRS/SICP less cs101?

submitted by nhjk
[link] [34 comments]
Categories: Incoming News

sdiehl (Stephen Diehl) · GitHub

del.icio.us/haskell - Wed, 02/18/2015 - 7:35am
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Type systems preventing laziness-related memoryleaks?

haskell-cafe - Wed, 02/18/2015 - 7:04am
Hello haskell-cafe, Let me repost here a question I posted to cstheory stackexchange - in hopes that there are more type theory experts here. http://cstheory.stackexchange.com/questions/29518/type-systems-preventing-laziness-related-memory-leaks Perhaps the main source of performance problems in Haskell is when a program inadvertently builds up a thunk of unbounded depth - this causes both a memory leak and a potential stack overflow when evaluating. The classic example is defining sum = foldr (+) 0 in Haskell. Are there any type systems which statically enforce lack of such thunks in a program using a lazy language? Seems like this should be on the same order of difficulty as proving other static program properties using type system extensions, e.g. some flavors of thread safety or memory safety. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
Categories: Offsite Discussion