Welcome to issue 271 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week of June 9 to 11, 2013. Quotes of the Week * cmccann: also please note that "malign" remains one of my best function names ever * dolio: Peak file descriptors is a myth. * mami: i think my brain rewired for higher typesystem compatibility in my sleep * elliott: it's impure but only depending on the environment! which is to say it is impure. * johnw: lens makes one into a mutating ninja * applicativ: een my language we say Z for one * DavidJacobs: Code is like poetry; most of it shouldn't have been written. * merijn: If I could program with arbitrary real world side effects I'd use "unsafeStabComputerUser" if someone attempted that * shachaf: Hackage going down regularly is part of the rustic charm of Haskell! * shachaf: JavaScript is the best example of a domain-specific language. Because of the same-origin policy. * chrisdone: [on being invited to help with idris development] dude i've already got 20 yaks lined up waiting to be shaved, don't send me a whole truck full * shachaf: edwardk isn't benevolent or malevolent. edwardk is more of a simple mechanical process tending toward maximal complexity. * AndrejBauer: When have you ever heard a category theorist say: I want to prove this diagram commutesâLet's suppose it doesn't. Top Reddit Stories * Applicative => Monad is coming. Domain: haskell.org, Score: 122, Comments: 62 On Reddit: [1] http://goo.gl/JCvQ4 Original: [2] http://goo.gl/fJxeX * The Homotopy Type Theory Book is now available for free online and in print at Lulu.com Domain: homotopytypetheory.org, Score: 86, Comments: 16 On Reddit: [3] http://goo.gl/x8nLW Original: [4] http://goo.gl/DR9gf * Three useful monads Domain: adit.io, Score: 71, Comments: 25 On Reddit: [5] http://goo.gl/WHqPr Original: [6] http://goo.gl/1r8nC * Beta sign up for FP Complete new IDE Domain: fpcomplete.com, Score: 63, Comments: 11 On Reddit: [7] http://goo.gl/RPV0P Original: [8] http://goo.gl/c03Od * HLearn implements more with 6 trivial lines of Haskell than Weka implements with over 100 complex lines of Java Domain: izbicki.me, Score: 47, Comments: 9 On Reddit: [9] http://goo.gl/EEqwS Original: [10] http://goo.gl/Ukk4E * Top secret School of Haskell articles leaked Domain: self.haskell, Score: 47, Comments: 17 On Reddit: [11] http://goo.gl/zhhYm Original: [12] http://goo.gl/zhhYm * F-algebra tutorial Domain: fpcomplete.com, Score: 41, Comments: 35 On Reddit: [13] http://goo.gl/Ybmbs Original: [14] http://goo.gl/szfGk * John Carmack on haskell today. Domain: self.haskell, Score: 40, Comments: 79 On Reddit: [15] http://goo.gl/8qHkt Original: [16] http://goo.gl/8qHkt * Data Flow Fusion with Series Expressions in Haskell Domain: justtesting.org, Score: 40, Comments: 19 On Reddit: [17] http://goo.gl/ZNeIP Original: [18] http://goo.gl/JAjjy * So you still don't understand Hindley-Milner? Part 1 Domain: akgupta.ca, Score: 38, Comments: 0 On Reddit: [19] http://goo.gl/OOk43 Original: [20] http://goo.gl/SZ1Gb * Ask HN: Any downsides of programming in Haskell? Domain: news.ycombinator.com, Score: 36, Comments: 104 On Reddit: [21] http://goo.gl/vRuHW Original: [22] http://goo.gl/fcleS * FP Complete - Haskell Introduction Domain: youtube.com, Score: 36, Comments: 12 On Reddit: [23] http://goo.gl/GqgC5 Original: [24] http://goo.gl/KoVYs * Fix your posture with haskell Domain: github.com, Score: 35, Comments: 2 On Reddit: [25] http://goo.gl/lznTr Original: [26] http://goo.gl/x21Ax * preprint list for ICFP'13 papers (additional links welcome) Domain: github.com, Score: 34, Comments: 9 On Reddit: [27] http://goo.gl/mZsTn Original: [28] http://goo.gl/bhbC9 * GHC: now with closed type families Domain: github.com, Score: 34, Comments: 15 On Reddit: [29] http://goo.gl/JJSSv Original: [30] http://goo.gl/QlV4s Top StackOverflow Questions * How to compare two functions for equivalence, as in (λx.2*x) == (λx.x+x)? votes: 15, answers: 2 Read on SO: [31] http://goo.gl/A6YDd * Should I use typeclasses or not? votes: 15, answers: 2 Read on SO: [32] http://goo.gl/EOV1M * Is there something like `map2 :: (i -> a) -> (i -> b) -> [i] -> [(a,b)]`? votes: 11, answers: 2 Read on SO: [33] http://goo.gl/WZyEy * Why isn't GeneralizedNewtypeDeriving a Safe Haskell? votes: 11, answers: 1 Read on SO: [34] http://goo.gl/on6Fc * It's not a monad, but what is it? votes: 10, answers: 0 Read on SO: [35] http://goo.gl/sm9gR * Writing efficient iterative loop for ST monad votes: 10, answers: 0 Read on SO: [36] http://goo.gl/WAAwA * Getting multiple results from map with “lens” votes: 10, answers: 2 Read on SO: [37] http://goo.gl/zqX8E * How to run Frege programs on Android? votes: 10, answers: 2 Read on SO: [38] http://goo.gl/XlSCN * Are there problems that can't be solved efficiently without arrays? [duplicate] votes: 9, answers: 0 Read on SO: [39] http://goo.gl/Z5j9a * Haskell: How to organize a group of functions that all take the same arguments votes: 9, answers: 4 Read on SO: [40] http://goo.gl/z64H7 Until next time, [41]+Daniel Santa Cruz References 1. http://www.haskell.org/haskellwiki/Functor-Applicative-Monad_Proposal 2. http://www.reddit.com/r/haskell/comments/1gsejt/applicative_monad_is_coming/ 3. http://homotopytypetheory.org/book/ 4. http://www.reddit.com/r/haskell/comments/1gr3uw/the_homotopy_type_theory_boo... 5. http://adit.io/posts/2013-06-10-three-useful-monads.html 6. http://www.reddit.com/r/haskell/comments/1g3a7e/three_useful_monads/ 7. https://www.fpcomplete.com/blog/2013/06/beta-sign-up 8. http://www.reddit.com/r/haskell/comments/1giy7l/beta_sign_up_for_fp_complete... 9. http://izbicki.me/blog/hlearns-code-is-shorter-and-clearer-than-wekas 10. http://www.reddit.com/r/haskell/comments/1g4v7u/hlearn_implements_more_with_... 11. http://www.reddit.com/r/haskell/comments/1g5k80/top_secret_school_of_haskell... 12. http://www.reddit.com/r/haskell/comments/1g5k80/top_secret_school_of_haskell... 13. https://www.fpcomplete.com/user/bartosz/understanding-algebras 14. http://www.reddit.com/r/haskell/comments/1g2g3s/falgebra_tutorial/ 15. http://www.reddit.com/r/haskell/comments/1g1mvx/john_carmack_on_haskell_toda... 16. http://www.reddit.com/r/haskell/comments/1g1mvx/john_carmack_on_haskell_toda... 17. http://justtesting.org/post/53175916852/data-flow-fusion-with-series-express... 18. http://www.reddit.com/r/haskell/comments/1gi5m1/data_flow_fusion_with_series... 19. http://akgupta.ca/blog/2013/05/14/so-you-still-dont-understand-hindley-milne... 20. http://www.reddit.com/r/haskell/comments/1g0ueo/so_you_still_dont_understand... 21. https://news.ycombinator.com/item?id=5893442 22. http://www.reddit.com/r/haskell/comments/1gknfs/ask_hn_any_downsides_of_prog... 23. https://www.youtube.com/watch?v=Fqi0Xu2Enaw 24. http://www.reddit.com/r/haskell/comments/1glw2o/fp_complete_haskell_introduc... 25. https://github.com/keera-studios/keera-posture 26. http://www.reddit.com/r/haskell/comments/1gr044/fix_your_posture_with_haskel... 27. https://github.com/gasche/icfp2013-papers#readme 28. http://www.reddit.com/r/haskell/comments/1gg2xf/preprint_list_for_icfp13_pap... 29. https://github.com/ghc/ghc/commit/569b26526403df4d88fe2a6d64c7dade09d003ad 30. http://www.reddit.com/r/haskell/comments/1gu2yl/ghc_now_with_closed_type_fam... 31. http://stackoverflow.com/questions/17045941/how-to-compare-two-functions-for... 32. http://stackoverflow.com/questions/17100036/should-i-use-typeclasses-or-not 33. http://stackoverflow.com/questions/17074424/is-there-something-like-map2-i-a... 34. http://stackoverflow.com/questions/17137111/why-isnt-generalizednewtypederiv... 35. http://stackoverflow.com/questions/17034427/its-not-a-monad-but-what-is-it 36. http://stackoverflow.com/questions/17126923/writing-efficient-iterative-loop... 37. http://stackoverflow.com/questions/17144334/getting-multiple-results-from-ma... 38. http://stackoverflow.com/questions/17222383/how-to-run-frege-programs-on-and... 39. http://stackoverflow.com/questions/17128103/are-there-problems-that-cant-be-... 40. http://stackoverflow.com/questions/17176829/haskell-how-to-organize-a-group-... 41. https://plus.google.com/105107667630152149014/about