[Haskell-cafe] Haskell Weekly News: Issue 171
Daniel Santa Cruz
dstcruz at gmail.com
Thu Mar 3 03:48:27 CET 2011
Welcome to issue 171 of the HWN, a newsletter covering developments
in the [1]Haskell community. This release covers the week of
February 20 - 26, 2011 .
Announcements
Eric Kow [2]announced that the Darcs project is staring to organize the
next hacking sprint, which will be "most likely in Paris in this
spring. If you fancy a weekend of hacking Haskell on a really neat real
world project, come join...!"
Jose Pedro Magalhaes [3]informed us of the initial release of htime, a
library to mimic the unix "time" utility.
Iain Alexander [4]annouced the initial release of data-type,
function-combine, and flexiwrap. "data-type contains a number of
fundamental types and classes useful for type-level programming, such
as type-level booleans, natural numbers, and lists."
I'd like to once again recognize some of the members of the community
that spend their time fielding questions from the new commers. If you
haven't been in the #haskell irc channel, you are just missing out!
There are also those who spend their time writting great answers to the
many questions in haskell's StackOverflow tag. You are what make this
community an inviting place for all the people interested in Haskell.
Keep it up!
Quotes of the Week
kmc: but rarely do beginners come to #haskell and say "i want to
append two lists, but i don't understand all this Monoid business, i
hear they're like taco salad"
Eduard:_Munteanu [In response to "GHC can go jump out a window" and
"GHC has already jumped out a window and flied and left you behind"]
Yes, GHC even implements optimizations such as defenestration.
Top Reddit Stories
* What kind of things are easy in Haskell and hard in Scala, and vice
versa?: From (programmers.stackexchange.com), scored 47 with 34
comments. Read on [5]reddit or the [6]original post.
* Multiday Debugging GHC: From (blog.ezyang.com), scored 37 with 2
comments. Read on [7]reddit or the [8]original post.
* Making OpenCL Simple with Haskell [pdf]: From (developer.amd.com),
scored 35 with 11 comments. Read on [9]reddit or the [10]original
post.
* GHC 7.0.2 RC 2 available. Please test!: From (haskell.org), scored
33 with 5 comments. Read on [11]reddit or the [12]original post.
* Minecraft data API for Haskell: HaskellNBT: From
(blog.acfoltzer.net), scored 27 with 4 comments. Read on [13]reddit
or the [14]original post.
* Dependently Typed Programming: an Agda Introduction: From
(youtube.com), scored 25 with 5 comments. Read on [15]reddit or the
[16]original post.
* Minecraft network protocol and proxy in Haskell: From (github.com),
scored 25 with 1 comments. Read on [17]reddit or the [18]original
post.
* Threading State - a short tutorial for new Haskell programmers:
From (mtnviewmark.wordpress.com), scored 22 with 3 comments. Read
on [19]reddit or the [20]original post.
* Solution (code) XCKD: Nerd Snipping: From
(pgraycode.wordpress.com), scored 20 with 8 comments. Read on
[21]reddit or the [22]original post.
* Agda 2.2 released: From (permalink.gmane.org), scored 18 with 1
comments. Read on [23]reddit or the [24]original post.
Top StackOverflow Answers
* [25]Feed elements of a tuple to a function as arguments in Haskell?
votes: 14
Function uncurry converts a two-argument (curried) function
into a function on pairs. Here's its type signature:
uncurry :: (a -> b -> c) -> (a, b) -> c
You need to use it on printf, like this:
mapM_ (uncurry $ printf "Values: %d %d\n")
[(1,100),(2,350),(3,600),(4,200)]
Another solution is to use pattern matching to deconstruct the
tuple, ...
* [26]What is the difference between different orderings of the same
monad transformers? votes: 10
Edit: I originally got the cases backwards. Fixed now.
The difference between orderings of monad transformer stacks
really only matters when you're peeling off layers of the
stack.
type Procedure a = MaybeT (State ProcedureState) a
In this case, you first run the MaybeT, which results in a
stateful computation which returns a Maybe a.
type Procedure a ...
Top StackOverflow Questions
* Real-world applications of zygohistomorphic prepromorphisms (votes:
54, answers: 2) [27]read
* How to roll a fast BVH representation in Haskell (votes: 10,
answers: 2) [28]read
* curious about how âloop = loopâ is evaluated in Haskell (votes: 9,
answers: 2) [29]read
* What is the difference between different orderings of the same
monad transformers? (votes: 8, answers: 3) [30]read
* haskell function declaration (votes: 6, answers: 3) [31]read
About the Haskell Weekly News
To help create new editions of this newsletter, please send stories to
dstcruz at gmail.com. I'm in dire need of finding good "quotes of the
week". If you happen to come across any, please don't hesitate to send
it along.
Until next time,
Daniel Santa Cruz
References
1. http://haskell.org/
2. http://article.gmane.org/gmane.comp.lang.haskell.cafe/86711
3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/86731
4. http://article.gmane.org/gmane.comp.lang.haskell.general/18526
5. http://www.reddit.com/r/haskell/comments/ft6eh/what_kind_of_things_are_easy_in_haskell_and_hard/
6. http://programmers.stackexchange.com/questions/51245/what-kind-of-things-are-easy-in-haskell-and-hard-in-scala-and-vice-versa
7. http://www.reddit.com/r/haskell/comments/fsp4f/multiday_debugging_ghc/
8. http://blog.ezyang.com/2011/02/multi-day-debugging/
9. http://www.reddit.com/r/haskell/comments/fqmmu/making_opencl_simple_with_haskell_pdf/
10. http://developer.amd.com/zones/OpenCLZone/publications/assets/MakingOpenCLSimplewithHaskell.pdf
11. http://www.reddit.com/r/haskell/comments/fp5e8/ghc_702_rc_2_available_please_test/
12. http://www.haskell.org/pipermail/glasgow-haskell-users/2011-February/020056.html
13. http://www.reddit.com/r/haskell/comments/fs2nw/minecraft_data_api_for_haskell_haskellnbt/
14. http://blog.acfoltzer.net/2010/12/minecraft-data-api-for-haskell-haskellnbt/
15. http://www.reddit.com/r/haskell/comments/fr5c1/dependently_typed_programming_an_agda_introduction/
16. http://www.youtube.com/view_play_list?p=44F162A8B8CB7C87
17. http://www.reddit.com/r/haskell/comments/fsgaq/minecraft_network_protocol_and_proxy_in_haskell/
18. https://github.com/glguy/minecraft-proxy
19. http://www.reddit.com/r/haskell/comments/fq4k4/threading_state_a_short_tutorial_for_new_haskell/
20. http://mtnviewmark.wordpress.com/2011/02/21/threading-state/
21. http://www.reddit.com/r/haskell/comments/fr9v7/solution_code_xckd_nerd_snipping/
22. http://pgraycode.wordpress.com/2011/02/23/solving-xkcds-nerd-snipping-problem/
23. http://www.reddit.com/r/haskell/comments/fp45s/agda_22_released/
24. http://permalink.gmane.org/gmane.comp.lang.agda/2566
25. http://stackoverflow.com/questions/5117948/feed-elements-of-a-tuple-to-a-function-as-arguments-in-haskell/5118105#5118105
26. http://stackoverflow.com/questions/5075621/what-is-the-difference-between-different-orderings-of-the-same-monad-transformers/5076096#5076096
27. http://stackoverflow.com/questions/5057136/real-world-applications-of-zygohistomorphic-prepromorphisms
28. http://stackoverflow.com/questions/5077243/how-to-roll-a-fast-bvh-representation-in-haskell
29. http://stackoverflow.com/questions/5126759/curious-about-how-loop-loop-is-evaluated-in-haskell
30. http://stackoverflow.com/questions/5075621/what-is-the-difference-between-different-orderings-of-the-same-monad-transformers
31. http://stackoverflow.com/questions/5073058/haskell-function-declaration
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