[Haskell-cafe] Munich Haskell Meeting

2013-01-28 Thread Heinrich Hördegen
Dear Haskellers, our monthly get-togethers in Munich this year start on Thursday, 31ts of January at 19h30. Our meeting venue will be Cafe Puck once again. If you want to join, please go to http://www.haskell-munich.de/dates and click the button. Of course, you can also invite all those

[Haskell-cafe] Mac os x (Intel, 10.6.8) problem compiling yesod-core-1.1.7.1

2013-01-28 Thread jean-christophe mincke
Hello GHC version : 7.4.2 When I do a cabal-dev instal yesod-core, I get the following error: Loading package blaze-builder-conduit-0.5.0.3 ... linking ... done. Loading package hashable-1.2.0.5 ... linking ... ghc: lookupSymbol failed in resolveImports

Re: [Haskell-cafe] catamorphisms and attribute grammars

2013-01-28 Thread Emil Axelsson
Patrick Bahr does something very similar in Modular Tree Automata [1], also noting the relation to attribute grammars. It's implemented in the compdata package [2]. [1] Patrick Bahr, Modular Tree Automata (MPC 2012), http://dx.doi.org/10.1007/978-3-642-31113-0_14 [2]

Re: [Haskell-cafe] Suggestiong for inter-thread communication

2013-01-28 Thread Mario Blažević
On 13-01-26 05:28 AM, Erik de Castro Lopo wrote: Thiago Negri wrote: Do you need advice on what? I didn't understand your last phrase. Well I have data from two sources, stdin and the calculation thread. If I was doing this in C, I'd probably use a pipe for the calculation data and then do

Re: [Haskell-cafe] Mac os x (Intel, 10.6.8) problem compiling yesod-core-1.1.7.1

2013-01-28 Thread Johan Tibell
Adding Bryan, who wrote this code. On Mon, Jan 28, 2013 at 1:23 AM, jean-christophe mincke jeanchristophe.min...@gmail.com wrote: Hello GHC version : 7.4.2 When I do a cabal-dev instal yesod-core, I get the following error: Loading package blaze-builder-conduit-0.5.0.3 ... linking ...

[Haskell-cafe] Uniplate and rewriting with different types

2013-01-28 Thread Chris Mears
Hi all, I have a question about the Uniplate library, regarding rewriting with transformations that have different types. With the following type, and transformation functions: data Odd = OddOne Even | OddZero Even deriving (Data,Typeable,Show) data Even = EvenOne Odd |

[Haskell-cafe] quotRem and divMod

2013-01-28 Thread Artyom Kazak
Hi! I’ve always thought that `quotRem` is faster than `quot` + `rem`, since both `quot` and `rem` are just wrappers that compute both the quotient and the remainder and then just throw one out. However, today I looked into the implementation of `quotRem` for `Int32` and found out that it’s

[Haskell-cafe] Type classes, collections, sum types, closures, and a massive headache

2013-01-28 Thread Bob Hutchison
Hi, I'm relatively new to Haskell, and consider myself to be towards the beginner side of the scale. Nevertheless, I've got this Haskell program I've been working on that's sitting around 11k lines right now. The pattern has been to let it grow to then knock it back by 'refactoring' or

Re: [Haskell-cafe] Type classes, collections, sum types, closures, and a massive headache

2013-01-28 Thread Taylor Hedberg
If I understand your message well enough, I think you are looking for GHC's `ExistentialQuantification` extension. Building heterogeneous collections is a common example of what existential types are useful for. Take a look at this wiki page [1]; there is an example of how to accomplish this

Re: [Haskell-cafe] Type classes, collections, sum types, closures, and a massive headache

2013-01-28 Thread Darren Grant
On Mon, Jan 28, 2013 at 5:43 PM, Bob Hutchison hutch-li...@recursive.cawrote: Now, this is how I got caught: it seems to be impossible to have collections of things with a common type class if they have different types. How is it that I've written that many lines of code in Haskell and I'm

Re: [Haskell-cafe] quotRem and divMod

2013-01-28 Thread Shachaf Ben-Kiki
On Mon, Jan 28, 2013 at 4:27 PM, Artyom Kazak artyom.ka...@gmail.com wrote: Hi! I’ve always thought that `quotRem` is faster than `quot` + `rem`, since both `quot` and `rem` are just wrappers that compute both the quotient and the remainder and then just throw one out. However, today I looked

[Haskell-cafe] Most used functions in hackage

2013-01-28 Thread Casey Basichis
Hi, I'm guessing this is a long shot, but Is there any link that counts the use of all functions in all packages in Hackage and lists them by frequency or by other stats? I'm still new to haskell but I've been working my way through tons and tons of tutorials and books. It would be very helpful

Re: [Haskell-cafe] Most used functions in hackage

2013-01-28 Thread Dmitry Vyal
On 01/29/2013 11:21 AM, Casey Basichis wrote: Is there any link that counts the use of all functions in all packages in Hackage and lists them by frequency or by other stats? I'm still new to haskell but I've been working my way through tons and tons of tutorials and books. It would be very