[Haskell-cafe] Haskell Weekly News
ky3 at atamo.com
Wed Apr 1 16:18:25 UTC 2015
- Bot attack on Trac
pummels GHC HQ productivity! Do you know a thing or two about hardening web
apps? Can you help?
- A month ago
you read about the absence of a correct operational spec for Core.
Baaij <http://ghc.haskell.org/trac/ghc/ticket/10121#comment:7> proffers
rewriting rules for something "very much like Core" from his 2014 thesis on
Digital Circuits in CλaSH, a tool designed for Computer Architecture for
Embedded Systems (CAES). The consensus is that they probably also work for
- Neil Mitchell reports Unable to load package Win32-188.8.131.52
<https://ghc.haskell.org/trac/ghc/ticket/10165>. The problem?
SetWindowLongPtrW exists only on 64-bit. The haskell win32 shim wasn't
switching to SetWindowLongW on 32-bit. Darren Grant steps up to offer a
fix, which Austin Seipp promptly checks in.
- Ki Yung Ahn
asks for a "wrapper that lifts actions of (State s1 a) to (State (s1,s2)
a). " The answer? A function called "zoom" in lens libraries.
- Chris Done
has started the ball rolling on GPG-based package signing. So far, Michael
Snoyman and Neil Mitchell have had their keys signed by Chris. He invites
others to join the party.
- Levant Erkok <https://ghc.haskell.org/trac/ghc/ticket/10215> joins Lennart
Augustsson <https://ghc.haskell.org/trac/ghc/ticket/9238> in hitting a
bug with signed zeros <http://en.wikipedia.org/wiki/Signed_zero>. The
function isNegativeZero breaks under optimizations.
- James Stevenson
over at Safari Books Online reveals how they use Haskell to parse web logs
more efficiently than Python. The top comment
<https://news.ycombinator.com/item?id=9294036> at Hacker News observes
the absence of a proper benchmark pitting Python vs Haskell. James responds
that they did an informal comparison that showed "the number of lines
parsed/second [with Python] was far smaller than the attoparsec-based
Elsewhere, Luke Randall
submits the link on reddit and thinks it's a "very gentle intro to parsing
- Ian Ross
announces a new C2HS release christened "Snowmelt". Originally authored by
Manuel Chakravarty, C2HS eases the pain of manually creating FFI shims for
C libraries. The latest release, thanks to work contributed by Philipp
Balzarek, achieves better cross-language alignment of C enum and Haskell
Enum types, among other improvements. Reddit discussion here.
- Michael Snoyman
FPComplete's open sourcing of their IDE backend, comprising a wrapper
around the GHC API.
- Jon Sterling at PivotCloud
<https://ghc.haskell.org/trac/ghc/ticket/9539#comment:2> hits an STM
TQueue bug initially reported by John Lato seven months ago. A sufficiently
fast writer can cause the reader to never get scheduled, which leads to
live-lock in Jon's production code. The fix looks to be as simple as
lazifying a case into a let in readTQueue. Curiously, the code uses
let in Simon
Marlow's book on Haskell concurrency
but not in the STM package you have on your machine.
*Tweets of the week:*
- Michael Neale
Quickcheck enters a bar, asks for 1 beer, 42 beers, -Inifinity beers,
shaves bartenders beard, sets off a tactical nuke.
- Dierk König <https://twitter.com/mittie/status/582803534950862848>:
#Haskell is the gold standard for programming languages and #Frege makes it
available on the #JVM
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