Haskell Weekly News
Issue 92 - November 08, 2008
Welcome to issue 92 of HWN, a newsletter covering developments in the
GHC 6.10 is released!! Go forth and drool over its new features. Be
sure to have the editline libraries (libedit-dev on Debian/Ubuntu, for
example) installed before you try building it.
GHC version 6.10.1. Ian Lynagh announced the release of GHC
version 6.10.1! This new major release features a number of significant
changes, including wild-card patterns, punning, and field
disambiguation in record syntax; generalised quasi-quotes; generalised
SQL-like list comprehensions; view patterns; a complete
reimplementation of type families; parallel garbage collection; a new
extensible exception framework; a more user-friendly API; included Data
Parallel Haskell (DPH); and more! See the full release notes for
new community.haskell.org features: webspace, mailing lists. Ian Lynagh
announced that the community server, http://community.haskell.org/,
has two new features for hosted projects: project webspace, and project
GHC blog. Simon Marlow has set up a GHC blog. This is for all
things related to GHC, particularly people working on GHC to blog about
what they're up to. If you want a write-bit, sign up for a wordpress
account, let Simon know your account name, and blog away! The GHC blog
should be syndicated on Planet Haskell soon.
Haddock 2.4.0. David Waern announced a new release of
Haddock, the Haskell documentation tool. This is a later version
than the one shipped with GHC 6.10.1, which is version 2.3.0. That
version will not be released on Hackage since it only builds with GHC
6.10.1 (by accident, actually). Besides adding back support for earlier
GHC versions, this release contains some more fixes and support for
htags-1.0. David Sankel announced the htags package, a tag file
generator to enable extra functionality in editors like vim. It expands
upon hasktags by using a full Haskell 98 parser and options for
Haskell Quick Reference (1-page PDF). Malcolm Wallace sent a 1-page
Haskell quick reference prepared for a recent Haskell tutorial.
Permission is granted for anyone to distribute it more widely as they
wish, in the hope that it might be useful. Editable sources can be
passed along if anyone would like to extend it.
Proposal for associated type synonyms in Template Haskell. Thomas van
Noort submitted a proposal for adding associated type synonyms to
Template Haskell. Comments are welcomed.
announce [("InfixApplicative", 1.0), ("OpenGLCheck", 1.0), ("obj",
0.1)]. Thomas Davie announced the upload of a few packages to
Hackage which he has produced while working at Anygma. obj-0.1 is a
library for loading and writing obj 3D models; OpenGLCheck-1.0 is a
micro-package containing instances of Arbitrary for the data structures
provided in Graphics.Rendering.OpenGL; and InfixApplicative-1.0 is
a second micro-package containing a pair of functions (<^) and (^>)
which can be used to provide an infix version of liftA2 applied to an
Graphalyze-0.5 and SourceGraph-0.3. Ivan Lazar Miljenovic announced
the latest versions of Graphalyze and SourceGraph, which fix a
couple of bugs in the previous versions.
zlib and bzlib 0.5 releases. Duncan Coutts announced updates to the
zlib and bzlib packages, featuring a slightly nicer extended
API. The simple API that most packages use is unchanged. There is also
a new parameter to control the size of the first output buffer; this
lets applications save memory when they happen to have a good estimate
of the output size.
Efficient parallel regular expressions. Martijn van Steenbergen
asked about efficiently running multiple regular expressions in
parallel, leading to an interesting discussion of regular expressions
and various parsing methods and libraries.
Problems with strictness analysis?. Patai Gergely started an
informative discussion about strictness, laziness, strictness
analysis, and compiler optimization. If you don't know a lot about
these topics but would like to learn, this thread is a good starting
1-year postdoc position in Chalmers Functional Programming group. John
Hughes announced a position for a post-doctoral researcher with the
Chalmers Functional Programming Group, with a one-year tax-free stipend
funded by Intel. The funded project will develop a Domain Specific
Language (DSL) for high level modelling, design and analysis of
hardware and microarchitectures.
Haskell news from the blogosphere.
* Edward Kmett: Still Alive. Edward is still alive but sadly lost
a few recursion scheme posts. =(
* >>> Max Rabkin: Beautiful folding. A very cool post about
* Eric Kow (kowey): timesheet helper.
* Philip Wadler: A bizarre function over streams.
* David Sankel: Introducing Reactive: Events. A very readable
introduction to the Reactive library. I look forward to reading
* "FP Lunch": Numbers vs Sets.
* Mark Jason Dominus: Addenda to recent articles 200810.
* Darcs: darcs weekly news #11.
* >>> Ken G.: Haskell?. Ken shares some thoughts on Real World
* Real-World Haskell: Some early reviews.
* David Sankel: freeglut + Windows + HOpenGL + HGLUT.
* GHC mutterings: GHC 6.10.1 is out!.
* Chung-chieh Shan: Cognitive jobs.
* London Haskell Users Group: Duncan Coutts: The Haskell
Platform. The abstract for Duncan's talk at the London HUG.
* Well-Typed.Com: GHC 6.10.1 released!.
* Well-Typed.Com: Haskell Platform talk at the London Haskell
* Mark Wassell: GIS with Haskell 1.
* >>> phoenix: Haskell Tricks: Indexing a List. Getting the index
of an element satisfying a predicate by zipping.
* JP Moresmau: Haskell for counting votes!. JP illustrates five
different voting methods with some Haskell implementations.
* Ivan Lazar Miljenovic: Graph Theoretic Analysis of
Relationships within Discrete Data.
* Braden Shepherdson: Pimp Your XMonad #1: Status bars. The first
in a planned series of articles on not-so-well-known ways to extend
your xmonad configuration.
* >>> Cory: Euler and Haskell. Cory just started learning Haskell
(a "fun, slightly ridiculous language") via Project Euler.
* >>> Sadek Drobi: Code Safety and Correctness is a matter of
Mindset Cultured by the Language.
* Well-Typed.Com: zlib and bzlib package updates.
* >>> Bryan St. Amour: Haskell Solution To The Farmer Problem.
* >>> Nathan Hartman: Haskell, Lambert, and the Clarke Ellipsoid.
Nathan has started porting a map projection library to Haskell.
* David Sankel: Analysis of lazy-stream programs..
Quotes of the Week
* Cory: Any language which makes frequent use of monads, functors and
has a wikibook describing its relation to category theory is the
result of an evil genius (or several, to be precise).
* mmorrow: in langs with dependent types, you can just map numbers
directly to types instead of having to ride a unicycle along a
tightrope while battling an unruly gang of monkeys with knives.
* conal: -fsemantics-shemantics
* roconnor: all sorts of wonderful things could be done if we are
less anal about bottoms. No pun intended.
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Haskell-Cafe mailing list
Brent Yorgey wrote:
> Haskell Weekly News
> Issue 92 - November 08, 2008
> GHC version 6.10.1. Ian Lynagh announced the release of GHC
> version 6.10.1! This new major release features a number of significant
> changes, including wild-card patterns, punning, and field
> disambiguation in record syntax; generalised quasi-quotes; generalised
> SQL-like list comprehensions; view patterns; a complete
> reimplementation of type families; parallel garbage collection; a new
> extensible exception framework; a more user-friendly API; included Data
> Parallel Haskell (DPH); and more! See the full release notes for
> more information.
Were it not for this message, I might never have noticed! :-}
(Presumably the main "announcement" was on one of the other Haskell
Anyway, I don't see it anywhere in the release notes, but I get the vibe
that type families are supposed to be "fully working" now. Is that
correct? If so, why no mention anywhere?
Also, the release notes tantelisingly hint that the long-awaited
parallel-array stuff is finally working in this release, but I can't
find any actual description of how to use it. All the DPH stuff seems on
the wiki was last updated many months ago. You would have thought that
such a big deal would be well-documented. It must have taken enough
effort to get it to work! You'd think somebody would want to shout about
Haskell-Cafe mailing list
> Anyway, I don't see it anywhere in the release notes, but I get the vibe
> that type families are supposed to be "fully working" now. Is that
> correct? If so, why no mention anywhere?
Type families have been completely reimplemented and should be stable
now, but there are some bugs - notably equality constraints in
superclasses are not supported in GHC 6.10.1, i.e.
> class (F a ~ b) => C a b where
> type F a
As indicated by this bug report: http://hackage.haskell.org/trac/ghc/ticket/2715
And here: http://haskell.org/haskellwiki/GHC/Indexed_types#Equality_constraints
> Also, the release notes tantelisingly hint that the long-awaited
> parallel-array stuff is finally working in this release, but I can't
> find any actual description of how to use it. All the DPH stuff seems on
> the wiki was last updated many months ago. You would have thought that
> such a big deal would be well-documented. It must have taken enough
> effort to get it to work! You'd think somebody would want to shout about
I put up a DPH version of the binarytrees benchmark in the shootout:
There are some notes there; the only documentation I really used was
the documentation built by the GHC build process on the 'dph-*'
libraries (you can see them in 6.10 by just doing 'ghc-pkg list' and
looking through it.)
I was thinking of porting more of the parallel shootout entries to use
DPH, but I'm busy right now - results could be interesting.
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