News aggregator

Typed label

haskell-cafe - Wed, 02/25/2015 - 3:12pm
Hi! I have a problem that seems very basic and fundamental, but at the same time I keep somehow skipping "the right way" to solve it. So I decided to give a try and describe it here. The task itself is very common. You have some data, which has some property inside of it. Often, you want to write a function that works only on an object with specific property being equal to something, but you can't move it out to type-parameter, because then you get all sorts of problems like you can't use regular lists/vectors anymore and other similar things. Let's take a look at real-world example to get a better understanding of a problem: Given a `Vegetable` type with a type that describes it's "type" (saying which concretely veg is it), you need to write a function `embraceOnion`, which would only work on onions (because it doesn't make sense to embrace any other veg). https://gist.github.com/k-bx/32b3f6a770ad81330f51 ``` {-# LANGUAGE DataKinds #-} {-# LANGUAGE KindSignatures #-} module Main where main :: I
Categories: Offsite Discussion

ajtulloch/caffegraph

del.icio.us/haskell - Wed, 02/25/2015 - 2:44pm
Categories: Offsite Blogs

ajtulloch/caffegraph

del.icio.us/haskell - Wed, 02/25/2015 - 2:44pm
Categories: Offsite Blogs

PowerPC variants (GHC 7.8.3)

haskell-cafe - Wed, 02/25/2015 - 2:11pm
Good morning, We have a product with an MPC8544E we might want to target. Also known as PowerQUICC and e500v2. The ABI is gnuspe rather than gnueabi. I have built a powerpc---ghc cross compiler but the thing stopping "hello world" is a SIGILL happening in StgCRun.c where the stfd and lfd instructions are used to stash registers. The e500 has different instructions but that cannot be dropped in trivially because of offset encoding Commenting these out fixes "hello world" though this surely only scratches the surface of what would need doing. I notice that whereas ARMv5, v6 and v7 appear to be catered for along with various knobs and whistles there appears to be no such thing for PowerPC. Is anybody else out there working on this area ? Jon
Categories: Offsite Discussion

news.ycombinator.com

del.icio.us/haskell - Wed, 02/25/2015 - 12:32pm
Categories: Offsite Blogs

news.ycombinator.com

del.icio.us/haskell - Wed, 02/25/2015 - 12:32pm
Categories: Offsite Blogs

CircuitHub is hiring Haskellers worldwide to fix manufacturing

Haskell on Reddit - Wed, 02/25/2015 - 12:04pm

CircuitHub is a place where engineers can upload their hardware design and turn it into a prototype or a product at the click of a button. The company is growing fast, counts many household names as customers and is backed by Google Ventures as well as Y Combinator.

We’re a tight-knit team, working remotely from multiple places around the world - currently London, South Africa and California. Our year is interspersed with regular retreats to (preferably exotic) locations to brainstorm on the product and direction of the company.

Our business model is founded on providing end-to-end automation along with an amazing user experience for our customers. To this end we emphasize a safe, maintainable code base that can be refactored quickly and easily in order to optimize daily operations. With this in mind we’ve made the switch from NodeJS to Haskell for almost all new software development. In a similar vein we are currently using Elm together with AngularJS and have already started to publish a couple of small open source packages.

Please feel free to ask questions here or apply to careers@circuithub.com.

EDIT: I'd like to add a thank you here for everyone who has sent us applications so far, we've had a great response. We'll reply to everyone who has sent us an email.

submitted by rehno-lindeque
[link] [12 comments]
Categories: Incoming News

[feature request] Make polymorphic functions more obvious in haddock.

Haskell on Reddit - Wed, 02/25/2015 - 11:10am

As it happens I just now have some spare time and bad connectivity. This is why I plug this feature request here for discussion as I can't get the haddock trac to load:

In light of the current AMP and FTP discussions there were (few) voices that claimed that more polymorphic functions would lead to more confusion when learning the language.

I propose a simple way that will probably reduce this confusion: enrich the haddock documentation with specialized versions of the typeclass instances.

Instead of just listing the instanced typeclasses list functions from the typeclass module, but instead of giving their polymorphic definitions list the specialized one for the current data type.

In turn this would mitigate another problem beginners are facing: for some datatypes it is not imediatly obvious what you can do with them because they take functionality from their class instances (Data.Sequence being a prime example there).

submitted by goliatskipson
[link] [22 comments]
Categories: Incoming News

Record Puns/Wildcards

glasgow-user - Wed, 02/25/2015 - 4:05am
I just noted that code like my_config = default_config {..} where name = "my project" description = "some longer text" gives me a syntax error, even if I have NamedFieldPuns and RecordWildCards extensions enabled. It seems that these extensions only work for record constructors and not for updating values. Is there a special reason puns/wildcards are not allowed in record updates? Cheers Ben
Categories: Offsite Discussion

Should foldl' be added to the post-"Plan FTP" Prelude

libraries list - Tue, 02/24/2015 - 10:42pm
(Cross-posted from haskell-cafe as suggested by Carter Schonwald) I would love to have foldl' as part of the Prelude. I use it quite frequently and it seems like a beginner trap to have foldl but not foldl' (which is almost always the better choice). I see that foldMap has been added (in addition to all of Monoid and Traversable), why was foldl' left out? It might be good measure to add foldr' as well, although I use that much less frequently. -bob _______________________________________________ Libraries mailing list Libraries< at >haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
Categories: Offsite Discussion

Should foldl' be added to the post-"Plan FTP"Prelude?

haskell-cafe - Tue, 02/24/2015 - 10:24pm
I would love to have foldl' as part of the Prelude. I use it quite frequently and it seems like a beginner trap to have foldl but not foldl' (which is almost always the better choice). I see that foldMap has been added (in addition to all of Monoid and Traversable), why was foldl' left out? It might be good measure to add foldr' as well, although I use that much less frequently. -bob _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
Categories: Offsite Discussion

Tutorials - HaskellWiki

del.icio.us/haskell - Tue, 02/24/2015 - 7:52pm
Categories: Offsite Blogs

Tutorials - HaskellWiki

del.icio.us/haskell - Tue, 02/24/2015 - 7:52pm
Categories: Offsite Blogs

Lisperati.com/haskell

del.icio.us/haskell - Tue, 02/24/2015 - 7:52pm
Categories: Offsite Blogs