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Spire Language Development Blog

del.icio.us/haskell - Sat, 05/03/2014 - 9:05pm
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Spire Language Development Blog

del.icio.us/haskell - Sat, 05/03/2014 - 9:05pm
Categories: Offsite Blogs

Composable events: Applicative and Alternative

haskell-cafe - Sat, 05/03/2014 - 7:02pm
Hi Cafe!! For my game Nomyx, I am using events that the player can program. For example, the player can register a callback that will be triggered when a new player arrives. He can also program some forms (with buttons, checkboxes, textboxes...) to appear on the Web GUI. The problem is those events are not composable: he has to create and handle them one by one. So I'm thinking of making those events composable by making them an instance of Applicative and Alternative. For Applicative, this makes events composable very much like in Applicative-Functors and Reform. I can build neat composed events such as (full program below): onInputMyRecord :: Event MyRecord onInputMyRecord = MyRecord <$> onInputText <*> onInputCheckbox For Alternative, I haven't seen any example of it on the net. The idea is that the first event that fires is used to build the alternative: onInputMyAlternative :: Event Bool onInputMyAlternative = (const True <$> onInputButton) <|> (const False <$> onInputButton) Here is an example pr
Categories: Offsite Discussion

Parallel Voronoi in Haskell

del.icio.us/haskell - Sat, 05/03/2014 - 6:34pm
Categories: Offsite Blogs

Parallel Voronoi in Haskell

del.icio.us/haskell - Sat, 05/03/2014 - 6:34pm
Categories: Offsite Blogs

jasani.org

del.icio.us/haskell - Sat, 05/03/2014 - 4:26pm
Categories: Offsite Blogs

jasani.org

del.icio.us/haskell - Sat, 05/03/2014 - 4:26pm
Categories: Offsite Blogs

cabal repl fails with GHC 7.8.2

haskell-cafe - Sat, 05/03/2014 - 3:13pm
I have a package for which "cabal repl" works fine with cabal version 1.20 and GHC 7.6.3. The package has a lot of FFI bindings and uses hsc2hs, so getting a REPL without "cabal repl" is a pain. The package also comes with the C sources that get linked in. But with GHC 7.8.2, "cabal repl" fails with: Loading object (static) dist/build/decnumber/src/decDouble.o ... /usr/bin/ld: dist/build/decnumber/src/decDouble.o: relocation R_X86_64_32S against `DPD2BIN' can not be used when making a shared object; recompile with -fPIC Any idea on how to fix this? "cabal build" and "cabal install" work fine and I can even build and execute a test binary against the library. It seems the problem is just with "cabal repl". Thanks. Omari
Categories: Offsite Discussion

Help faking DDTs

Haskell on Reddit - Sat, 05/03/2014 - 2:11pm

I am trying to build a data type to control a structure similar to a list, with the difference that we might add arrows to elements. Furthermore, I require that some functions operate only on lists where the number of Up arrows and Down arrows is exactly equal to 1.

Things went smoothly, until I try to convert a normal list to the richer list: Code here (the commented block at the end will not work!)

Any suggestions on how to fix things, or maybe simplifying it.

submitted by BanX
[link] [7 comments]
Categories: Incoming News

extensible records - Vinyl - alternatives?

haskell-cafe - Sat, 05/03/2014 - 11:16am
Dear All, I'm searching a handsome library for handling large amounts of configuration data in a flexible manner. So to speak I want to use some kind of inheritance of data fields. I think this is where the extensible records discussion is a proper description of my use case. I've found 2 libraries making this work, so far: HList Vinyl I currently prefer Vinyl due to the complex types in HList, lens compatibiliy, named labels. (I love the HList and OOHaskel papers, but for practical use, I currently prefer Vinyl). What do you think, what is the best way nowadays to use extensible records? Is Vinyl a good choice from your point of view? regards Peter _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Categories: Offsite Discussion

How far away are we from commercial functional-programming-based hardware?

Haskell on Reddit - Sat, 05/03/2014 - 9:29am

I know of the (Reduceron)[http://www.cs.york.ac.uk/fp/reduceron/], I'm wondering how long it will be until research like this is finished, chips are produced, and I can build a computer based on functional paradigms.

Are others interested in a computer like this? It must be clear there's a niche market here.

submitted by fifosine
[link] [12 comments]
Categories: Incoming News

www.youtube.com

del.icio.us/haskell - Sat, 05/03/2014 - 6:36am
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twdkz.wordpress.com

del.icio.us/haskell - Sat, 05/03/2014 - 6:21am
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Experimenting a new plotting library

haskell-cafe - Fri, 05/02/2014 - 10:44pm
Hi cafe, I'm experimenting a new plotting library which makes use of the API of diagrams. I decided to start this work, because: 1. There is few plotting library written in pure Haskell 2. Haskell-chart, one of the most featured library, is hard to extend and there is no straightforward way to compose or modify the plots generated by this library. I had some ideas for the new library. You can get some feeling from here: https://github.com/kaizhang/haskell-plot I'm still relatively new to haskell and don't have much experience in making plots either. Hopefully I can get some suggestions from you guys and improve my programming skills through this process. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
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