[Haskell-cafe] Haskell Weekly News

Fri May 15 12:07:09 UTC 2015

*Top Picks:*

   - Is Servant <http://haskell-servant.github.io/>the most type-safe HTTP
   server library ever? Are the type signatures hard to read
   <https://news.ycombinator.com/item?id=9519782#up_9520750>? In addition
   to its utmost relevance as a web library, Servant is also an awesome case
   study in the type safety vs type readability trade-off spectrum, brought to
   you by Alp Mestanogullari and Julian Arni. HN
   <https://news.ycombinator.com/item?id=9519782> and /r/haskell

   <http://www.reddit.com/r/haskell/comments/35hiie/servant_04_released/>
   - Ozan Sener compiles Pandoc into JS via GHCJS and creates a web
   interface to it using the Reflex FRP library
   <https://github.com/ryantrinkle/reflex>. Markup.Rocks
   <https://github.com/osener/markup.rocks> is much loved on /r/haskell
   <http://www.reddit.com/r/haskell/comments/35ax22/ive_compiled_pandoc_with_ghcjs_and_built_an/>.
   See also HN <https://news.ycombinator.com/item?id=9512293>.

   - Is Haskell a "Startup Secret Weapon"? Alexandr Kurilin reveals adoption
   challenges
   <https://github.com/commercialhaskell/commercialhaskell/blob/master/usage/frontrow.md>
   at Front Row Education
   <https://www.crunchbase.com/organization/front-row>. Among them, slow
   build times. Also, "senior developers [that] get very frustrated when
   something wouldn't compile for hours and they couldn't find any help to
   move forward." Comments on HN
   <https://news.ycombinator.com/item?id=9519924> and /r/haskell
   <http://www.reddit.com/r/haskell/comments/35h8vh/how_front_row_education_uses_haskell_for_nearly/>
   .

   - At Facebook, Bryan O'Sullivan debugs aeson's gigabyte space leak
   <http://www.serpentine.com/blog/2015/05/13/sometimes-the-old-ways-are-the-best/>
   on decoding a JSON megabyte of non-stop backslashes. Culprit? The streaming
   interface didn't match the use case. In place of streaming, Bryan now
   blasts bytes into a single big buffer, gaining 27x speed and 42x memory
   reduction. Comments on HN <https://news.ycombinator.com/item?id=9540389>,
   Proggit
   <http://www.reddit.com/r/programming/comments/35udjh/fixing_a_haskell_performance_bug_sometimes_the/>,
   /r/haskell
   <http://www.reddit.com/r/haskell/comments/35udfy/fixing_an_aeson_performance_bug_sometimes_the_old/>
   .

   - Paul Chiusano's Unison programming platform
   <http://unisonweb.org/2015-05-07/about.html> hits the HN
   <https://news.ycombinator.com/item?id=9512955> and /r/haskell
   <http://www.reddit.com/r/haskell/comments/35cop9/unison_a_nextgeneration_programming_platform/>
   headlines. Features include a browser-based UI that constrains edits to
   those that are well-typed. Also, DRY-ness up the wazoo: every type and term
   is uniquely identified by a hash a la Git.

   - Joey Hess reports
   <http://www.reddit.com/r/haskell/comments/35bw0b/at_last_debian_unstable_has_working_arm_ghci_and/>
   that Debian unstable now has a working GHCi for ARM. The Template Haskell
   challenges have been surmounted.

   - Garrison Jensen blows the whistle
   <http://www.garrisonjensen.com/2015/05/13/haskell-programs-are-lies.html>
   on the impostor sieve on the front page of Haskell.org. In jest. A festive
   one-upmanship of fondly treasured code ensues on /r/haskell
   <http://www.reddit.com/r/haskell/comments/35vc31/the_real_way_to_generate_a_list_of_primes_in/>.
   And since bad publicity is better than no publicity, we owe kudos to
   Garrison. HN-worthy <https://news.ycombinator.com/item?id=9541478>.

   - Michael Snoyman decries use of ExceptT IO
   <https://www.fpcomplete.com/user/commercial/content/exceptions-best-practices>
   for exception handling because the user exception data type creates
   misleading expectations of comprehensiveness. The gotcha is that it doesn't
   cover IO exceptions! Furthermore, distinct exception types mean that the
   corresponding code can't compose. Instead? Use MonadThrow. /r/haskell


   <http://www.reddit.com/r/haskell/comments/35sk6w/best_practices_for_using_exceptions_an_fp/>
   - JP Moresmau steps down as chief of EclipseFP
   <http://jpmoresmau.blogspot.com/2015/05/eclipsefp-end-of-life-from-me-at-least.html>
   and the companion Haskell packages BuildWrapper, ghc-pkg-lib, and
   scion-browser. Without anyone to take his place, the sun sets on EclipseFP.
   But the sun continues to shine on ide-backend (previously reported
   <http://haskell.1045720.n5.nabble.com/Haskell-Weekly-News-td5768107.html>),
   a GHC API wrapper akin to BuildWrapper. JP spitballs
   <http://haskell.1045720.n5.nabble.com/IDE-backend-Atom-editor-td5809240.html>
   on how he might move on to the Atom editor, jiggering it to use
   ide-backend-client. /r/haskell


   <http://www.reddit.com/r/haskell/comments/35y5v1/jp_moresmaus_blog_eclipsefp_end_of_life/>
   - Tatsuya Hirose translates Go By Example into Haskell. GBE
   <https://gobyexample.com/> comprises code samples annotated for an
   experienced programmer new to Go. For this first cut
   <http://lotz84.github.io/haskellbyexample/>, Tatsuya stays close to the
   original and creates Go-ish, imperative Haskell. Already good for
   Go-to-Haskell crossovers. Potentially excellent when done in idiomatic
   Haskell. /r/haskell

   <http://www.reddit.com/r/haskell/comments/3586e3/haskell_by_example/>
   - Tomas Petricek observes <http://tomasp.net/blog/2015/against-types/>
   the diversity of  type theories and type systems and posits harm in any
   attempt at a single all-encompassing capture of the meaning of 'types'.
   What about unsound types? He doesn't offer a way out for those stuck with
   the appellation. Comments on HN
   <https://news.ycombinator.com/item?id=9545540> and /r/haskell
   <http://www.reddit.com/r/haskell/comments/35zzvu/against_the_definition_of_types_by_tomas_petricek/>
   .

   - John De Goes launches a crowdfund
   <https://www.indiegogo.com/projects/record-all-lambdaconf-2015-talks> to
   solicit $15,000 for video-recording 70 talks at LambdaConf 2015, which
   features many known Haskell programmers. /r/haskell


   <http://www.reddit.com/r/haskell/comments/35n14p/indiegogo_record_all_lambdaconf_2015_talks/>
   - A redditor asks ex-Lispers what it's like moving to Haskell
   <http://www.reddit.com/r/haskell/comments/35bybo/lispers_of_haskell_whats_your_experience_using/>.
   "I miss Lisp parens" is a frequent answer. Also, Lisp has a better REPL
   experience. A biggie upside? The refactoring afforded by Haskell's type
   system.


*Tip of the Week:*

   - When programming fractals, use the LLVM backend
   <https://ghc.haskell.org/trac/ghc/ticket/10400#comment:3> because it's
   "usually good at optimizing this kind of non-allocating code" as Reid
   Barton advises.


-- Kim-Ee
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