- Haskell-Cafe - Haskell.org

Embedding the GHC API
by Joel Reymont 01 Nov '07

01 Nov '07

Has anyone tried to embed GHC as a library recently? What is the size of the resulting binary? I'm assuming a bare minimum of needed libraries. Thanks, Joel -- http://wagerlabs.com

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Why can't Haskell be faster?
by Paulo J. Matos 01 Nov '07

01 Nov '07

Hello all, I, along with some friends, have been looking to Haskell lately. I'm very happy with Haskell as a language, however, a friend sent me the link: http://shootout.alioth.debian.org/gp4/ which enables you compare several language implementations. Haskell seems to lag behind of Clean. >From what I've seen of Clean it seems almost like Haskell. It even distributes a Haskell->Clean translator so the obvious question is, why is Haskell slower? Being similar languages and being GHC a very good compiler, can't it get at least as fast as Clean? What am I missing here? (I wrote this mail assuming the results from the URL are trustworthy). Cheers, -- Paulo Jorge Matos - pocm at soton.ac.uk http://www.personal.soton.ac.uk/pocm PhD Student @ ECS University of Southampton, UK

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virtual lambda
by Alberto Ruiz 01 Nov '07

01 Nov '07

Hi, I think that you may like the following demo of a simple computer vision application powered by Haskell: http://covector.blogspot.com/2007/10/functional-augmented-reality.html Alberto

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Haskell libraries for computer vision
by Don Stewart 01 Nov '07

01 Nov '07

http://alberrto.googlepages.com/easyvision "An experimental Haskell system for fast prototyping of computer vision and image processing applications." Looks ridiculously cool. -- Don

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Re: Why can't Haskell be faster?
by david48 31 Oct '07

31 Oct '07

I'd like to see Supero and Jhc - compiled examples in the language shootout.

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Type inference problem with division (/)
by noa 31 Oct '07

31 Oct '07

Hi! I have the following function: theRemainder :: [String] -> [String] -> Double theRemainder xs xt = sum( map additional (unique xs) ) where additional x = poccur * (inf [ppos,pneg]) --inf takes [Double] where xsxt = zip xs xt pi = countPos xr -- countPos returns an Int ni = (length xr) - pi len = length xs len2 = length xr ppos = pi/len2 -- THESE ARE THE PROBLEM pneg = ni/len2 -- THESE ARE THE PROBLEM poccur = (pi+ni)/len xr = (filter ((\y -> (fst y)==x)) (xsxt)) And I am getting this error message with ghc: matrix.hs:54:31: Couldn't match expected type `Double' against inferred type `Int' In the expression: ppos In the first argument of `inf', namely `[ppos, pneg]' In the second argument of `(*)', namely `(inf [ppos, pneg])' How can I change the declaration of ppos nad pneg so they are treated as Double for the inf function? Cheers, Nick -- View this message in context: http://www.nabble.com/Type-inference-problem-with-division-%28-%29-tf472211… Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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does the order of splice definitions matter in template haskell, or is this a bug?
by Thomas Hartman 31 Oct '07

31 Oct '07

I have a situation where ... stuff... $(expose ['setState, 'getState] f = SetState compiles but f = SetState $(expose ['setState, 'getState] doesn't compile, with error: Not in scope: data constructor 'SetState. Is this a bug? expose is defined in HAppS.State.EventTH t,. --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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help needed packaging curl bindings
by brad clawsie 31 Oct '07

31 Oct '07

i have decided to take on the task of packaging-up (for hackage) and documenting the curl bindings as available here: http://code.haskell.org/curl/ if the originators of this code are reading this and do not wish me to proceed please say so, i won't be offended otherwise i was wondering if people had good examples to point me to for providing the cross-platform support needed for a FFI-based module such as this. i have made the necessary changes to compile the code on freebsd, but for other platforms i am not sure at all, particularly non-unix style platforms like windows. my guess is that providing cross-platform support requires autoconf etc prior to the hackage build process (?) any info/references appreciated thanks brad

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Re: [Haskell-cafe] Why can't Haskell be faster?
by manu 31 Oct '07

31 Oct '07

>> From what I've seen of Clean it seems almost like Haskell. It even >> > distributes a Haskell->Clean translator so the obvious question is, > why is Haskell slower? > It's also something I've wondered about, and I'm curious about the answer... One of the differences between Haskell and Clean is how side-effects are allowed (Uniqueness Types for Clean, and Monadic I/O for Haskell) GHC also supports a lot of extensions beyong Haskell98. Does it explain the difference in performances ? I don't know... Experts please ! Manu

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Re[2]: [Haskell] Image manipulation
by Bulat Ziganshin 31 Oct '07

31 Oct '07

Hello Bjorn, Wednesday, October 31, 2007, 11:54:33 AM, you wrote: > data fields. Data Field Haskell had a function to force the evaluation of > all elements in a data field at once. this looks like a parallel arrays? -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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