- Glasgow-haskell-users

Parallel Profiling
by Dominic Steinitz 30 Mar '15

30 Mar '15

Does anyone know of any tools for analysing parallel program performance? I am trying to use threadscope but it keeps crashing with my 100M log file and ghc-events-analyze is not going to help as I have many hundreds of threads all carrying out the same computation. I think I’d like a library that would allow me to construct my own analyses rather than display them via GTK. There is ghc-events but that seems to be just for parsing the logs and I couldn’t find anything that used it in the way I would like to (apart from threadscope and ghc-events-analyze of course). Thanks Dominic Steinitz dominic(a)steinitz.org http://idontgetoutmuch.wordpress.com

1 0

ANNOUNCE: GHC version 7.10.1
by Austin Seipp 27 Mar '15

27 Mar '15

============================================================== The (Interactive) Glasgow Haskell Compiler -- version 7.10.1 ============================================================== The GHC Team is pleased to announce a new major release of GHC. There have been a number of significant changes since the last major release, including: * Several new language features and changes have been implemented: - Applicative is now a superclass of Monad and in the Prelude. - Many prelude combinators have been generalized - Static pointers * GHC now has preliminary and experimental support for DWARF based debugging. * `integer-gmp` has been completely rewritten. * Type-checking plugins can now extend the type checker. * Support for partial type signatures * Many bugfixes and other performance improvements. * Preliminary support for 'backpack' features like signatures. * Typeable is now generated by default for all data types automatically. We've also fixed a handful of issues reported since RC3: - A bug in the call arity analysis that would result in invalid core was fixed (#10176) - A bug in the Win32 package causing it to fail to load was fixed (#10165) - ghc-prim has (correctly) been bumped to version 0.4.0.0, to comply with the PVP. - Several libraries have been bumped to their latest available versions after coordination. The full release notes are here: https://downloads.haskell.org/~ghc/7.10.1/docs/html/users_guide/release-7-1… How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: https://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://ghc.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: https://ghc.haskell.org/trac/ghc/wiki/Platforms https://ghc.haskell.org/trac/ghc/wiki/CodeOwners Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: https://ghc.haskell.org/trac/ghc/wiki/Building Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: https://ghc.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at https://www.haskell.org/mailman/listinfo/glasgow-haskell-users https://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see https://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: https://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: https://www.haskell.org/ghc/reportabug Hashes & Signatures ~~~~~~~~~~~~~~~~~ On https://downloads.haskell.org/~ghc/7.10.1/ you will find a signed copy of the SHA256 hashes for the tarballs, using my GPG key (0F8F 3AA9 9235 C704 ADA0 B419 B942 AEE5 3B58 D86F). -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

2 1

Splices returning splices
by J. Garrett Morris 23 Mar '15

23 Mar '15

Hello, I'm attempting to write a quasiquoter with relatively full antiquotation support. In doing so, I've arrived at I think an odd problem: the expression grammar in Language.Haskell.TH.Syntax doesn't seem to include splices. This seems to mean that my antiquotations can't themselves include splices, which is quite limiting. Am I misinterpreting? The type system in "Template metaprogramming for Haskell" seems to imply no such restriction on the occurrences of splices. (As an additional complication: what I really need to do is return typed splices; my "quasiquoter" relies on its expected type to determine its behavior. However, this seems like an uninteresting extension of the above problem.) Thanks, /g -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

2 2

ANNOUNCE: GHC 7.10.1 Release Candidate 3
by Austin Seipp 19 Mar '15

19 Mar '15

We are pleased to announce the third release candidate for GHC 7.10.1: https://downloads.haskell.org/~ghc/7.10.1-rc3 https://downloads.haskell.org/~ghc/7.10.1-rc3/docs/html/ This includes the source tarball and bindists for Windows and Debian Linux. FreeBSD, CentOS and Mac OS X binary distributions will follow soon. These binaries and tarballs have an accompanying SHA256SUMS file signed by my GPG key id (0x3B58D86F). We plan to make the 7.10.1 final release at the end of this week - so please test as much as possible; bugs are much cheaper if we find them before the release! The list of issues we plan on fixing can always be found in an up-to-date form here: https://ghc.haskell.org/trac/ghc/wiki/Status/GHC-7.10.1 -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

11 13

Re: ANNOUNCE: GHC 7.10.1 Release Candidate 3
by Miëtek Bak 17 Mar '15

17 Mar '15

As I wrote previously — the bindist name does mention ‘deb7’, so perhaps this is all working as intended, and perhaps supporting such ancient distributions is not actually needed. However, the GHC 7.8.4, 7.8.3, and 7.8.2 bindists work fine with glibc 2.11, so this is a regression. -- Miëtek On 2015-03-17, at 08:25, Herbert Valerio Riedel <hvriedel(a)gmail.com> wrote: > On 2015-03-17 at 03:09:23 +0100, Miëtek Bak wrote: >> As with 7.10.1-rc2, installation fails on CentOS 6 (i386), Debian 6, and Ubuntu 10.04 LTS, in one of two following ways — >> >> 1. On i386: >> >> "utils/ghc-cabal/dist-install/build/tmp/ghc-cabal-bindist" copy libraries/ghc-prim dist-install "strip" '' '/app/ghc' '/app/ghc/lib/ghc-7.10.0.20150316' '/app/ghc/share/doc/ghc/html/libraries' 'v p dyn' >> ghc-cabal/dist-install/build/tmp/ghc-cabal: symbol lookup error: libraries/integer-gmp2/dist-install/build/libHSinteger-gmp-1.0.0.0-6zeGtnFHpaVBJ80QaL9uVu-ghc7.10.0.20150316.so: undefined symbol: __gmpn_ior_n > > Well, it shouldn't be very surprising that the deb7 (wheezy) ghc bindist > doesn't work on deb6 (squeeze), as it's been compile-time configured for > the environment provided by deb7 which has newer libraries with more > features/symbols. > > So what's needed here is probably a 2nd linux bindist build on an > ancient enough (i.e. the one with the oldest libraries among > CentOS6/Deb6/Ubuntu10.04) Linux environment.

2 1

Qualified names in TH?
by J. Garrett Morris 17 Mar '15

17 Mar '15

I'm trying to write some Template Haskell code that (among other things) manipulates IntSets. So, for example, I'd like a splice to generate a call to Data.IntSet.fromList. However, I'm not sure how IntSet will be imported in the target module. Is there a way to resolve the fully qualified name (or similar) to a TH Name, without having to know how it's imported in the splicing module? (The obvious approach---mkName "Data.IntSet.fromList"---seems not to work in GHC 7.8.) Thanks! /g -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

3 2

[PATCH] generalize filterM, mapAndUnzipM, zipWithM, zipWithM_, replicateM, replicateM_
by M Farkas-Dyck 16 Mar '15

16 Mar '15

--- libraries/base/Control/Monad.hs | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/libraries/base/Control/Monad.hs b/libraries/base/Control/Monad.hs index 6fa4a07..02eabd1 100644 --- a/libraries/base/Control/Monad.hs +++ b/libraries/base/Control/Monad.hs @@ -75,9 +75,9 @@ module Control.Monad , (<$!>) ) where -import Data.Foldable ( Foldable, sequence_, msum, mapM_, foldlM, forM_ ) -import Data.Functor ( void ) -import Data.Traversable ( forM, mapM, sequence ) +import Data.Functor ( void, (<$>) ) +import Data.Foldable ( Foldable, sequence_, sequenceA_, msum, mapM_, foldlM, forM_ ) +import Data.Traversable ( forM, mapM, traverse, sequence, sequenceA ) import GHC.Base hiding ( mapM, sequence ) import GHC.List ( zipWith, unzip, replicate ) @@ -94,13 +94,8 @@ guard False = empty -- | This generalizes the list-based 'filter' function. {-# INLINE filterM #-} -filterM :: (Monad m) => (a -> m Bool) -> [a] -> m [a] -filterM p = foldr go (return []) - where - go x r = do - flg <- p x - ys <- r - return (if flg then x:ys else ys) +filterM :: (Applicative m) => (a -> m Bool) -> [a] -> m [a] +filterM p = foldr (\ x -> liftA2 (\ flg -> if flg then (x:) else id) (p x)) (pure []) infixr 1 <=<, >=> @@ -125,19 +120,19 @@ forever a = let a' = a >> a' in a' -- | The 'mapAndUnzipM' function maps its first argument over a list, returning -- the result as a pair of lists. This function is mainly used with complicated -- data structures or a state-transforming monad. -mapAndUnzipM :: (Monad m) => (a -> m (b,c)) -> [a] -> m ([b], [c]) +mapAndUnzipM :: (Applicative m) => (a -> m (b,c)) -> [a] -> m ([b], [c]) {-# INLINE mapAndUnzipM #-} -mapAndUnzipM f xs = sequence (map f xs) >>= return . unzip +mapAndUnzipM f xs = unzip <$> traverse f xs --- | The 'zipWithM' function generalizes 'zipWith' to arbitrary monads. -zipWithM :: (Monad m) => (a -> b -> m c) -> [a] -> [b] -> m [c] +-- | The 'zipWithM' function generalizes 'zipWith' to arbitrary applicative functors. +zipWithM :: (Applicative m) => (a -> b -> m c) -> [a] -> [b] -> m [c] {-# INLINE zipWithM #-} -zipWithM f xs ys = sequence (zipWith f xs ys) +zipWithM f xs ys = sequenceA (zipWith f xs ys) -- | 'zipWithM_' is the extension of 'zipWithM' which ignores the final result. -zipWithM_ :: (Monad m) => (a -> b -> m c) -> [a] -> [b] -> m () +zipWithM_ :: (Applicative m) => (a -> b -> m c) -> [a] -> [b] -> m () {-# INLINE zipWithM_ #-} -zipWithM_ f xs ys = sequence_ (zipWith f xs ys) +zipWithM_ f xs ys = sequenceA_ (zipWith f xs ys) {- | The 'foldM' function is analogous to 'foldl', except that its result is encapsulated in a monad. Note that 'foldM' works from left-to-right over @@ -175,18 +170,18 @@ foldM_ f a xs = foldlM f a xs >> return () -- | @'replicateM' n act@ performs the action @n@ times, -- gathering the results. -replicateM :: (Monad m) => Int -> m a -> m [a] +replicateM :: (Applicative m) => Int -> m a -> m [a] {-# INLINEABLE replicateM #-} {-# SPECIALISE replicateM :: Int -> IO a -> IO [a] #-} {-# SPECIALISE replicateM :: Int -> Maybe a -> Maybe [a] #-} -replicateM n x = sequence (replicate n x) +replicateM n x = sequenceA (replicate n x) -- | Like 'replicateM', but discards the result. -replicateM_ :: (Monad m) => Int -> m a -> m () +replicateM_ :: (Applicative m) => Int -> m a -> m () {-# INLINEABLE replicateM_ #-} {-# SPECIALISE replicateM_ :: Int -> IO a -> IO () #-} {-# SPECIALISE replicateM_ :: Int -> Maybe a -> Maybe () #-} -replicateM_ n x = sequence_ (replicate n x) +replicateM_ n x = sequenceA_ (replicate n x) -- | The reverse of 'when'. unless :: (Applicative f) => Bool -> f () -> f () -- 2.3.1

1 0

-staticlib flag for building standalone static libraries producing very large libraries
by Sean Seefried 07 Mar '15

07 Mar '15

Hi all, Can anyone explain the following problem I'm having? I'm currently writing a game in Haskell. When I produce a plain old executable (for local testing) it's about 23M. However, when I create a static lib using the -staticlib flag it is 54M. Why the discrepancy? Sean

2 1

Record Puns/Wildcards
by Ben Franksen 25 Feb '15

25 Feb '15

I just noted that code like my_config = default_config {..} where name = "my project" description = "some longer text" gives me a syntax error, even if I have NamedFieldPuns and RecordWildCards extensions enabled. It seems that these extensions only work for record constructors and not for updating values. Is there a special reason puns/wildcards are not allowed in record updates? Cheers Ben -- "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." ― C.A.R. Hoare

2 2

Re: [Haskell-cafe] PowerPC variants (GHC 7.8.3)
by Carter Schonwald 25 Feb '15

25 Feb '15

Hey Jon, I do know that some of the GHC dev team is probably best equipped to answer your question, i'm cc'ing the ghc dev and users lists so they can jump in and help! -Carter On Wed, Feb 25, 2015 at 7:11 AM, Jon Schneider <haskell(a)jschneider.net> wrote: > Good morning, > > We have a product with an MPC8544E we might want to target. Also known as > PowerQUICC and e500v2. The ABI is gnuspe rather than gnueabi. > > I have built a powerpc---ghc cross compiler but the thing stopping "hello > world" is a SIGILL happening in StgCRun.c where the stfd and lfd > instructions are used to stash registers. The e500 has different > instructions but that cannot be dropped in trivially because of offset > encoding Commenting these out fixes "hello world" though this surely only > scratches the surface of what would need doing. > > I notice that whereas ARMv5, v6 and v7 appear to be catered for along with > various knobs and whistles there appears to be no such thing for PowerPC. > > Is anybody else out there working on this area ? > > Jon > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe >

1 0