<div dir="ltr"><div>Welcome to issue 255 of the HWN, an issue covering crowd-sourced bits</div><div>of information about Haskell from around the web. This issue covers the</div><div>weeks of January 06 to 19, 201.</div><div>
<br></div><div>Quotes of the Week</div><div><br></div><div> * ky3: Indexed monads are just categories in the category of</div><div> endofunctors, what's the problem?</div><div><br></div><div> * tac: I guess I'm just living in a fantasy world where the docs tell</div>
<div> you how to use such a basic API :P</div><div><br></div><div> * shachaf: 3.0 is an edwardk phase, not just a version number. It's</div><div> like Picasso's Blue Period.</div><div><br></div><div> * cmccann: Clearly the reason why edwardk uses Haskell now is because</div>
<div> every C++ compiler has a restraining order against him.</div><div><br></div><div> * shachaf: I'm not sure what your question is, but maybe lens is the</div><div> answer.</div><div><br></div><div> * cmccann: * cmccann has concluded that lenses are just a category</div>
<div> whose objects are english prepositions and whose morphisms are all</div><div> unsafeCoerce</div><div><br></div><div> * shachaf: Some people, when asking about a problem in #haskell, get</div><div> a link to <a href="http://okmij.org">okmij.org</a>. Now they have two problems.</div>
<div><br></div><div> * quicksilver: It returns undefined for convenience. I'm not really</div><div> sure it's that convenient, but that's why.</div><div><br></div><div> * edwardk: cmccann: let me get this straight you are saying that</div>
<div> someone [mm_freak] who by their very nick admits to being a freak</div><div> did something freakish?</div><div><br></div><div>Top Reddit Stories</div><div><br></div><div> * LiquidHaskell: Refinement Types in Haskell via SMT</div>
<div> Domain: <a href="http://goto.ucsd.edu">goto.ucsd.edu</a>, Score: 71, Comments: 22</div><div> On Reddit: [1] <a href="http://goo.gl/PE2nf">http://goo.gl/PE2nf</a></div><div> Original: [2] <a href="http://goo.gl/P3Gm9">http://goo.gl/P3Gm9</a></div>
<div><br></div><div> * Hakyll 4.0 released</div><div> Domain: <a href="http://jaspervdj.be">jaspervdj.be</a>, Score: 59, Comments: 19</div><div> On Reddit: [3] <a href="http://goo.gl/IQAXq">http://goo.gl/IQAXq</a></div>
<div> Original: [4] <a href="http://goo.gl/AbLnM">http://goo.gl/AbLnM</a></div><div><br></div><div> * When Haskell is faster than C</div><div> Domain: <a href="http://paulspontifications.blogspot.co.uk">paulspontifications.blogspot.co.uk</a>, Score: 52, Comments: 23</div>
<div> On Reddit: [5] <a href="http://goo.gl/3rj8J">http://goo.gl/3rj8J</a></div><div> Original: [6] <a href="http://goo.gl/N2cbA">http://goo.gl/N2cbA</a></div><div><br></div><div> * I'm teaching an introductory 12-week class on Haskell. </div>
<div> Join in for a journey!</div><div> Domain: <a href="http://reddit.com">reddit.com</a>, Score: 45, Comments: 15</div><div> On Reddit: [7] <a href="http://goo.gl/TsnQ5">http://goo.gl/TsnQ5</a></div><div> Original: [8] <a href="http://goo.gl/EMMVR">http://goo.gl/EMMVR</a></div>
<div><br></div><div> * Subtractable values are torsors</div><div> Domain: <a href="http://ro-che.info">ro-che.info</a>, Score: 42, Comments: 15</div><div> On Reddit: [9] <a href="http://goo.gl/4IcMp">http://goo.gl/4IcMp</a></div>
<div> Original: [10] <a href="http://goo.gl/6YJrY">http://goo.gl/6YJrY</a></div><div><br></div><div> * Chordify: extract chord sequences from MP3's using HarmTrace</div><div> Domain: <a href="http://chordify.net">chordify.net</a>, Score: 42, Comments: 8</div>
<div> On Reddit: [11] <a href="http://goo.gl/8J7rA">http://goo.gl/8J7rA</a></div><div> Original: [12] <a href="http://goo.gl/ySfR5">http://goo.gl/ySfR5</a></div><div><br></div><div> * Getting Started with Haskell</div>
<div> Domain: <a href="http://bob.ippoli.to">bob.ippoli.to</a>, Score: 41, Comments: 8</div><div> On Reddit: [13] <a href="http://goo.gl/4Evnb">http://goo.gl/4Evnb</a></div><div> Original: [14] <a href="http://goo.gl/nzg9o">http://goo.gl/nzg9o</a></div>
<div><br></div><div> * Using AngularJS with Haskell Snap</div><div> Domain: <a href="http://nurpax.github.com">nurpax.github.com</a>, Score: 40, Comments: 19</div><div> On Reddit: [15] <a href="http://goo.gl/SH8e1">http://goo.gl/SH8e1</a></div>
<div> Original: [16] <a href="http://goo.gl/0lSyN">http://goo.gl/0lSyN</a></div><div><br></div><div> * Down with kinds: adding dependent heterogeneous equality to to FC</div><div> Domain: <a href="http://cis.upenn.edu">cis.upenn.edu</a>, Score: 38, Comments: 14</div>
<div> On Reddit: [17] <a href="http://goo.gl/iEvyI">http://goo.gl/iEvyI</a></div><div> Original: [18] <a href="http://goo.gl/cH0Eo">http://goo.gl/cH0Eo</a></div><div><br></div><div> * Fixing GADTs : Generic recursion schemes for GADTs using fixed </div>
<div> points of higher-order functors</div><div> Domain: <a href="http://timphilipwilliams.com">timphilipwilliams.com</a>, Score: 38, Comments: 25</div><div> On Reddit: [19] <a href="http://goo.gl/dEMq9">http://goo.gl/dEMq9</a></div>
<div> Original: [20] <a href="http://goo.gl/vnjhp">http://goo.gl/vnjhp</a></div><div><br></div><div> * What's the importance of Category Theory in Haskell? Is it worth </div><div> really studying?</div><div>
Domain: self.haskell, Score: 37, Comments: 60</div><div> On Reddit: [21] <a href="http://goo.gl/T430r">http://goo.gl/T430r</a></div><div> Original: [22] <a href="http://goo.gl/T430r">http://goo.gl/T430r</a></div>
<div><br></div><div> * Parsing Markdown with Parsec: How Pandoc does it</div><div> Domain: <a href="http://youtube.com">youtube.com</a>, Score: 35, Comments: 13</div><div> On Reddit: [23] <a href="http://goo.gl/TN9TJ">http://goo.gl/TN9TJ</a></div>
<div> Original: [24] <a href="http://goo.gl/zpX7f">http://goo.gl/zpX7f</a></div><div><br></div><div> * Clckwrks, from the creator of Happstack, is developing into a clean </div><div> alternative to Wordpress</div>
<div> Domain: <a href="http://clckwrks.com">clckwrks.com</a>, Score: 34, Comments: 7</div><div> On Reddit: [25] <a href="http://goo.gl/L9WXx">http://goo.gl/L9WXx</a></div><div> Original: [26] <a href="http://goo.gl/FZRpU">http://goo.gl/FZRpU</a></div>
<div><br></div><div> * pipes-safe-1.0 - Resource management and exception handling for pipes</div><div> Domain: <a href="http://haskellforall.com">haskellforall.com</a>, Score: 32, Comments: 27</div><div> On Reddit: [27] <a href="http://goo.gl/HeLWz">http://goo.gl/HeLWz</a></div>
<div> Original: [28] <a href="http://goo.gl/1hTFc">http://goo.gl/1hTFc</a></div><div><br></div><div>Top StackOverflow Questions</div><div><br></div><div> * values, types, kinds,… as an infinite sequence?</div><div>
votes: 36, answers: 1</div>
<div> Read on SO: [29] <a href="http://goo.gl/lyyYc">http://goo.gl/lyyYc</a></div><div><br></div><div> * Why is this a useful warning in Haskell when pattern matching? </div><div> “Defined but not used”</div><div>
votes: 17, answers: 3</div><div> Read on SO: [30] <a href="http://goo.gl/iQLFq">http://goo.gl/iQLFq</a></div><div><br></div><div> * Why are getArgs and getProgName IO actions?</div><div> votes: 16, answers: 3</div>
<div> Read on SO: [31] <a href="http://goo.gl/5ZPYO">http://goo.gl/5ZPYO</a></div><div><br></div><div> * Can GADTs be used to prove type inequalities in GHC? [duplicate]</div><div> votes: 14, answers: 2</div><div>
Read on SO: [32] <a href="http://goo.gl/fDdha">http://goo.gl/fDdha</a></div><div><br></div><div> * Applying Denotational Semantics to design of Programs [migrated]</div><div> votes: 14, answers: 0</div><div> Read on SO: [33] <a href="http://goo.gl/KLOCX">http://goo.gl/KLOCX</a></div>
<div><br></div><div> * Examples where compiler-optimized functional code performs better </div><div> than imperative code</div><div> votes: 14, answers: 1</div><div> Read on SO: [34] <a href="http://goo.gl/Fzqdx">http://goo.gl/Fzqdx</a></div>
<div><br></div><div> * Why is there only one non-strict function from Int to Int?</div><div> votes: 12, answers: 2</div><div> Read on SO: [35] <a href="http://goo.gl/KXcAy">http://goo.gl/KXcAy</a></div><div><br>
</div><div> * Dependency injection in Haskell: solving the task idiomatically</div><div> votes: 12, answers: 3</div><div> Read on SO: [36] <a href="http://goo.gl/xTcYc">http://goo.gl/xTcYc</a></div><div><br></div>
<div> * What does a Haskell comment starting with `{- |` generally mean?</div><div> votes: 11, answers: 1</div><div> Read on SO: [37] <a href="http://goo.gl/zNikw">http://goo.gl/zNikw</a></div><div><br></div><div>
* Is operational really isomorphic to a free monad?</div><div> votes: 10, answers: 3</div><div> Read on SO: [38] <a href="http://goo.gl/AJlgH">http://goo.gl/AJlgH</a></div><div><br></div><div><br></div><div>Until next time,</div>
<div>[39]+Daniel Santa Cruz</div><div><br></div><div>References</div><div><br></div><div> 1. <a href="http://goto.ucsd.edu/~rjhala/liquid/haskell/blog/blog/2013/01/01/refinement-types-101.lhs/">http://goto.ucsd.edu/~rjhala/liquid/haskell/blog/blog/2013/01/01/refinement-types-101.lhs/</a></div>
<div> 2. <a href="http://www.reddit.com/r/haskell/comments/16w3hp/liquidhaskell_refinement_types_in_haskell_via_smt/">http://www.reddit.com/r/haskell/comments/16w3hp/liquidhaskell_refinement_types_in_haskell_via_smt/</a></div>
<div> 3. <a href="http://jaspervdj.be/posts/2013-01-16-hakyll-4.0.html">http://jaspervdj.be/posts/2013-01-16-hakyll-4.0.html</a></div><div> 4. <a href="http://www.reddit.com/r/haskell/comments/16ojtv/hakyll_40_released/">http://www.reddit.com/r/haskell/comments/16ojtv/hakyll_40_released/</a></div>
<div> 5. <a href="http://paulspontifications.blogspot.co.uk/2013/01/when-haskell-is-faster-than-c.html">http://paulspontifications.blogspot.co.uk/2013/01/when-haskell-is-faster-than-c.html</a></div><div> 6. <a href="http://www.reddit.com/r/haskell/comments/16tryo/when_haskell_is_faster_than_c/">http://www.reddit.com/r/haskell/comments/16tryo/when_haskell_is_faster_than_c/</a></div>
<div> 7. <a href="http://www.reddit.com/r/UniversityofReddit/comments/169jfe/class_introduction_to_haskell/">http://www.reddit.com/r/UniversityofReddit/comments/169jfe/class_introduction_to_haskell/</a></div><div> 8. <a href="http://www.reddit.com/r/haskell/comments/169k67/im_teaching_an_introductory_12week_class_on/">http://www.reddit.com/r/haskell/comments/169k67/im_teaching_an_introductory_12week_class_on/</a></div>
<div> 9. <a href="http://ro-che.info/articles/2013-01-08-torsors.html">http://ro-che.info/articles/2013-01-08-torsors.html</a></div><div> 10. <a href="http://www.reddit.com/r/haskell/comments/166iju/subtractable_values_are_torsors/">http://www.reddit.com/r/haskell/comments/166iju/subtractable_values_are_torsors/</a></div>
<div> 11. <a href="http://chordify.net/pages/how-to-use-chordify/">http://chordify.net/pages/how-to-use-chordify/</a></div><div> 12. <a href="http://www.reddit.com/r/haskell/comments/16u44u/chordify_extract_chord_sequences_from_mp3s_using/">http://www.reddit.com/r/haskell/comments/16u44u/chordify_extract_chord_sequences_from_mp3s_using/</a></div>
<div> 13. <a href="http://bob.ippoli.to/archives/2013/01/11/getting-started-with-haskell/">http://bob.ippoli.to/archives/2013/01/11/getting-started-with-haskell/</a></div><div> 14. <a href="http://www.reddit.com/r/haskell/comments/16fegr/getting_started_with_haskell/">http://www.reddit.com/r/haskell/comments/16fegr/getting_started_with_haskell/</a></div>
<div> 15. <a href="http://nurpax.github.com/posts/2013-01-13-angularjs-and-haskell.html">http://nurpax.github.com/posts/2013-01-13-angularjs-and-haskell.html</a></div><div> 16. <a href="http://www.reddit.com/r/haskell/comments/16iaiq/using_angularjs_with_haskell_snap/">http://www.reddit.com/r/haskell/comments/16iaiq/using_angularjs_with_haskell_snap/</a></div>
<div> 17. <a href="http://www.cis.upenn.edu/~eir/papers/2013/jmnokinds/jmnokinds.pdf">http://www.cis.upenn.edu/~eir/papers/2013/jmnokinds/jmnokinds.pdf</a></div><div> 18. <a href="http://www.reddit.com/r/haskell/comments/167c21/down_with_kinds_adding_dependent_heterogeneous/">http://www.reddit.com/r/haskell/comments/167c21/down_with_kinds_adding_dependent_heterogeneous/</a></div>
<div> 19. <a href="http://www.timphilipwilliams.com/posts/2013-01-16-fixing-gadts.html">http://www.timphilipwilliams.com/posts/2013-01-16-fixing-gadts.html</a></div><div> 20. <a href="http://www.reddit.com/r/haskell/comments/16qr6q/fixing_gadts_generic_recursion_schemes_for_gadts/">http://www.reddit.com/r/haskell/comments/16qr6q/fixing_gadts_generic_recursion_schemes_for_gadts/</a></div>
<div> 21. <a href="http://www.reddit.com/r/haskell/comments/16i322/whats_the_importance_of_category_theory_in/">http://www.reddit.com/r/haskell/comments/16i322/whats_the_importance_of_category_theory_in/</a></div><div> 22. <a href="http://www.reddit.com/r/haskell/comments/16i322/whats_the_importance_of_category_theory_in/">http://www.reddit.com/r/haskell/comments/16i322/whats_the_importance_of_category_theory_in/</a></div>
<div> 23. <a href="http://www.youtube.com/watch?v=nCwG9ijQMuQ&t=01m22s">http://www.youtube.com/watch?v=nCwG9ijQMuQ&t=01m22s</a></div><div> 24. <a href="http://www.reddit.com/r/haskell/comments/16kf0j/parsing_markdown_with_parsec_how_pandoc_does_it/">http://www.reddit.com/r/haskell/comments/16kf0j/parsing_markdown_with_parsec_how_pandoc_does_it/</a></div>
<div> 25. <a href="http://www.clckwrks.com/">http://www.clckwrks.com/</a></div><div> 26. <a href="http://www.reddit.com/r/haskell/comments/168j2w/clckwrks_from_the_creator_of_happstack_is/">http://www.reddit.com/r/haskell/comments/168j2w/clckwrks_from_the_creator_of_happstack_is/</a></div>
<div> 27. <a href="http://www.haskellforall.com/2013/01/pipes-safe-10-resource-management-and.html">http://www.haskellforall.com/2013/01/pipes-safe-10-resource-management-and.html</a></div><div> 28. <a href="http://www.reddit.com/r/haskell/comments/16mban/pipessafe10_resource_management_and_exception/">http://www.reddit.com/r/haskell/comments/16mban/pipessafe10_resource_management_and_exception/</a></div>
<div> 29. <a href="http://stackoverflow.com/questions/14401689/values-types-kinds-as-an-infinite-sequence">http://stackoverflow.com/questions/14401689/values-types-kinds-as-an-infinite-sequence</a></div><div> 30. <a href="http://stackoverflow.com/questions/14309396/why-is-this-a-useful-warning-in-haskell-when-pattern-matching-defined-but-not">http://stackoverflow.com/questions/14309396/why-is-this-a-useful-warning-in-haskell-when-pattern-matching-defined-but-not</a></div>
<div> 31. <a href="http://stackoverflow.com/questions/14295582/why-are-getargs-and-getprogname-io-actions">http://stackoverflow.com/questions/14295582/why-are-getargs-and-getprogname-io-actions</a></div><div> 32. <a href="http://stackoverflow.com/questions/14273235/can-gadts-be-used-to-prove-type-inequalities-in-ghc">http://stackoverflow.com/questions/14273235/can-gadts-be-used-to-prove-type-inequalities-in-ghc</a></div>
<div> 33. <a href="http://stackoverflow.com/questions/14349232/applying-denotational-semantics-to-design-of-programs">http://stackoverflow.com/questions/14349232/applying-denotational-semantics-to-design-of-programs</a></div>
<div> 34. <a href="http://stackoverflow.com/questions/14357918/examples-where-compiler-optimized-functional-code-performs-better-than-imperativ">http://stackoverflow.com/questions/14357918/examples-where-compiler-optimized-functional-code-performs-better-than-imperativ</a></div>
<div> 35. <a href="http://stackoverflow.com/questions/14262014/why-is-there-only-one-non-strict-function-from-int-to-int">http://stackoverflow.com/questions/14262014/why-is-there-only-one-non-strict-function-from-int-to-int</a></div>
<div> 36. <a href="http://stackoverflow.com/questions/14327327/dependency-injection-in-haskell-solving-the-task-idiomatically">http://stackoverflow.com/questions/14327327/dependency-injection-in-haskell-solving-the-task-idiomatically</a></div>
<div> 37. <a href="http://stackoverflow.com/questions/14270500/what-does-a-haskell-comment-starting-with-generally-mean">http://stackoverflow.com/questions/14270500/what-does-a-haskell-comment-starting-with-generally-mean</a></div>
<div> 38. <a href="http://stackoverflow.com/questions/14263363/is-operational-really-isomorphic-to-a-free-monad">http://stackoverflow.com/questions/14263363/is-operational-really-isomorphic-to-a-free-monad</a></div><div>
39. <a href="https://plus.google.com/105107667630152149014/about">https://plus.google.com/105107667630152149014/about</a></div><div><br></div></div>