Re: [Haskell-cafe] Compilers
On 2008 Nov 26, at 16:58, Matthias Kilian wrote: On Wed, Nov 26, 2008 at 09:35:01PM +, Andrew Coppin wrote: It is a fork of the JHC compiler, which should be easier to look up. There is also Hugs, as you mentioned. In addition, you may want to look at YHC and NHC. Yeah, the implementations page on the Wiki basically says that there's GHC and Hugs, and there's also these things called YHC, NHC and JHC. All the documentation I've read makes these latter compilers sound highly experimental and unusable. I would't call nhc experimental; it's quite usable, at least for standard Haskell-98 stuff (plus some language extensions). On a related topic: whatever happened to the compiler shootout? (Aside from dons leaving unsw) -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Compilers
allbery: On 2008 Nov 26, at 16:58, Matthias Kilian wrote: On Wed, Nov 26, 2008 at 09:35:01PM +, Andrew Coppin wrote: It is a fork of the JHC compiler, which should be easier to look up. There is also Hugs, as you mentioned. In addition, you may want to look at YHC and NHC. Yeah, the implementations page on the Wiki basically says that there's GHC and Hugs, and there's also these things called YHC, NHC and JHC. All the documentation I've read makes these latter compilers sound highly experimental and unusable. I would't call nhc experimental; it's quite usable, at least for standard Haskell-98 stuff (plus some language extensions). On a related topic: whatever happened to the compiler shootout? (Aside from dons leaving unsw) Malcolm continues the tradition, http://code.haskell.org/nobench/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] workarounds for Codec.Compression.Zlib errors in darcs
Jason Dagit [EMAIL PROTECTED] writes: That is, if you use the optional specification of a header file for each foreign import, and if your Haskell compiler can compile via C, then any checking that types match between Haskell and C can be performed automatically, by the backend C compiler. Would this method work with return types since C compilers tend to let you ignore those? In this example that brought up this discussion it was in fact an ignored return value that caused the problem. I've tried to look at GCC's warning options, but couldn't make it emit a warning on an ignored result. (Doesn't mean it isn't in there, of course) -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Windows vs. Linux x64
Bartosz Wójcik [EMAIL PROTECTED] writes: Win32 Core2Duo 1.8GHz 1GB RAM 17 Mb total memory in use MUT time 56.97s ( 57.02s elapsed) %GC time 0.5% Win32 Core2Duo 2.2GHz 2GB RAM 17 Mb total memory in use MUT time 57.44s ( 57.53s elapsed) %GC time 0.7% (0.8% elapsed) So, despite the CPU being 25% faster, it's exactly as fast. Memory bound? Win32 P4 2.8GHz 1GB RAM 17 Mb total memory in use MUT time 171.64s (175.78s elapsed) %GC time 1.7% (1.5% elapsed) You're doing divisions, and I seem to remember division being an operation that wreaked havoc with the P4's ALU or trace cache, or something like that. Linux64 Core2Duo 2.2GHz 2GB RAM 41 MB total memory in use (1 MB lost due to fragmentation) MUT time 68.26s ( 68.92s elapsed) %GC time 0.9% (1.1% elapsed) Linux32 Core2Duo 2.3GHz 4GB RAM 17 Mb total memory in use MUT time 51.77s ( 51.83s elapsed) %GC time 0.5% (0.6% elapsed) Interesting that Linux32 is actually faster than Win32. Different cache sizes? -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Need machine for DPH benchmarking
we, the DPH team, are at the moment in the very unfortunate situation of not having a proper machine for running our benchmarks on. Could a kind soul maybe give us (i.e., me) access to a quadcore or 2xquadcore x86 Linux or OS X machine? I only need to build ghc on it and run small benchmarks which never take more than a couple of minutes, maybe once every couple of days or so. We do need to use all cores, though, so no other CPU-intensive processes can be running during benchmarking. This is only for a week or two, until we get our own machine. We would be eternally grateful and won't forget you when DPH takes over the world. Roman Roman, Graeme can set you up on an 8 core machine if you email him. Dominic. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] workarounds for Codec.Compression.Zlib errors in darcs
On Wed, 2008-11-26 at 23:16 +, Malcolm Wallace wrote: ... to work out the C types and then map them to Haskell ones, to check they're the same as the declared types in the .hs files. I'd like to point out that the FFI specification already has such a mechanism. That is, if you use the optional specification of a header file for each foreign import, and if your Haskell compiler can compile via C, then any checking that types match between Haskell and C can be performed automatically, by the backend C compiler. Yes, it would have caught a similar problem in an argument position, but not in the result. [ OK, so that is not the whole story, and there are good reasons why it might not always work out, but I still think it was an important principle in the original FFI design. ] And covering those holes requires a tool that can grok C. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Philip Wadler video on Howard-Curry Correspondence ???
Incidentally, Haskell is mentioned several times in the Dr. Dobbs Journal article on the Wadler paper: Dr. Dobb's | Old ideas form the basis of advancements in functional programming | 12 1, 2000 http://www.ddj.com/showArticle.jhtml?articleID=184404384 Specifically: Languages that took more direct inspiration from lambda calculus include: ... Haskell, named for Haskell Curry (Hudak, Peyton Jones, Wadler, and others, 1987; see http://haskell.org/). and Standard ML is noted for its exploration of module types, Haskell for its type classes, and O'Caml for its object-oriented types. Standard ML, Haskell, and O'Caml are all continuing development, and innovation in their type systems is one of the principal directions of research. and Applications built on top of functional languages, and which themselves use type systems in innovative ways, include: ... Lolita, a natural language understanding system (implemented in Haskell) ... and ... Yarrow in Haskell (http://www.cs.kun.nl/~janz/ yarrow/) ... The article discusses the impact of logic on functional programming, citing examples including those involving Haskell, and mentions a correspondence between types and proofs. -- Benjamin L. Russell On Thu, 27 Nov 2008 20:33:37 +0900, Benjamin L.Russell [EMAIL PROTECTED] wrote: On Wed, 26 Nov 2008 23:48:19 -0600, Galchin, Vasili [EMAIL PROTECTED] wrote: Hello, I am reading re-reading Prof. Wadler paper Proofs are Programs: 19th Century Logic and 21st Century Computing but also want to re-read watch his video on same subject. ??? There is a reference to the video in question at the following site, but the link seems to be broken: Proofs are Programs: 19th Century Logic and 21st Century Computing | Lambda the Ultimate http://lambda-the-ultimate.org/node/1447 The same link is also mentioned at the following site as well: Wadler: History of logic and programming languages http://homepages.inf.ed.ac.uk/wadler/topics/history.html The (broken) link mentioned at the above two sites is the following: TechNetCast Archives http://technetcast.ddj.com/tnc_catalog.html?item_id=1011 However, attempting to visit the above-mentioned site results in the following error message: Query Failed1 Since the same URL is mentioned at both sites, this error is unlikely to be the result of a typo. Perhaps either the item was removed, or the hosting server is down? You may wish to try reaching the contact person for the site hosting the video, Dr. Dobb's TechNetCast (see http://technetcast.ddj.com/), at [EMAIL PROTECTED] -- Benjamin L. Russell ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Problem getting code from AFP08 parallel tutorial to run in parallel
On Tue, Nov 25, 2008 at 11:07 PM, Don Stewart [EMAIL PROTECTED] wrote: What does the code look like? It looks like that. Of course it doesn't compute the same number as the initial code, but it starts 3 sparks and I get the expected 100% CPU usage instead of 50%. parSumFibEuler :: Int - Int - Int - Int parSumFibEuler a b c = f `par` (e `par` (g `pseq` (f + e + g))) where f = fib a e = sumEuler b g = sumEuler c r1 :: Int r1 = parSumFibEuler 40 7450 7449 Instead of: parSumFibEuler :: Int - Int - Int parSumFibEuler a b = f `par` (e `pseq` (f + e)) where f = fib a e = sumEuler b r1 :: Int r1 = parSumFibEuler 40 7450 Olivier. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Philip Wadler video on Howard-Curry Correspondence ???
2008/11/27 Galchin, Vasili [EMAIL PROTECTED]: Hello, I am reading re-reading Prof. Wadler paper Proofs are Programs: 19th Century Logic and 21st Century Computing but also want to re-read watch his video on same subject. Is it this talk you're after? http://video.google.com/videoplay?docid=-4167170843018186532ei=sI0uSZT7Faf22gKd9NTqDQq=wadler+philip Cheers, Josef ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Compilers
Am 27.11.2008 um 09:23 schrieb Don Stewart: allbery: On 2008 Nov 26, at 16:58, Matthias Kilian wrote: On Wed, Nov 26, 2008 at 09:35:01PM +, Andrew Coppin wrote: It is a fork of the JHC compiler, which should be easier to look up. There is also Hugs, as you mentioned. In addition, you may want to look at YHC and NHC. Yeah, the implementations page on the Wiki basically says that there's GHC and Hugs, and there's also these things called YHC, NHC and JHC. All the documentation I've read makes these latter compilers sound highly experimental and unusable. I would't call nhc experimental; it's quite usable, at least for standard Haskell-98 stuff (plus some language extensions). On a related topic: whatever happened to the compiler shootout? (Aside from dons leaving unsw) Malcolm continues the tradition, http://code.haskell.org/nobench/ All result links are broken. PGP.sig Description: Signierter Teil der Nachricht ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] haddock question
Dear all I'm trying to locally build the documentation for the haskell-src-exts package and running into a bit of bother. If I run: cabal haddock I get the error: haddock: parse error in doc string so: cabal haddock -v Doesn't really provide any extra information, it gives me the exact haddock command-line used but there is still no way (I can see) of obtaining the source file containing the parse error. So I downloaded via darcs the latest haddock source code and installed that but I get the exact same error message. I tried grepping in the haddock source code for that particular error message (and portions of it) but I couldn't find it. Finally I tried running haddock on a single source file: haddock Language/Haskell/Exts.hs and even this gets the exact same error message, which is somewhat bizarre since that file does not contain any documentation strings. Anyone have any ideas? regards allan -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
pbkdf2 on hackage Re: Re[2]: [Haskell-cafe] Password hashing
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/PBKDF2
Since no one took up my code review request I just did the best I
could and uploaded to hackage. There were indeed some mistakes in my
initial post, fixed now. (Code review is still wished, though!)
Alas, documentation doesn't build with hackage, altough it does for me
locally. (Seems like almost everything I do these days -- what am I
doing wrong?!)
Also I'm open to folding this into a more established crypto package
if there are any takers... psst, dominic.
Also, dominic, shouldn't your crypto package be added to category
Cryptography (a cabal file change) so it lists aside the other crypto
packages?
thanks, thomas.
2008/11/26 Thomas Hartman [EMAIL PROTECTED]:
Sorry about the hideous formatting above. Reattached as a text file.
t.
2008/11/26 Thomas Hartman [EMAIL PROTECTED]:
OK, I went ahead and implemented pbkdf2, following the algorithm
linked to by bulat and Michael.
If there are any crypto gurus who can code-review this I would be much
obliged, and when I'm confident enough that this does the right thing
I'll put it up on hackage.
I don't do much crypto so this *definitely* needs a review before it
becomes a library?
How's this looks, cafe?
Thanks!
Thomas.
{-# LANGUAGE ScopedTypeVariables #-}
module Crypto.PBKDF2 (pbkdf2, pbkdf2') where
import qualified Data.ByteString.Char8 as B
import qualified Data.ByteString.Lazy as L
import GHC.Word
import Control.Monad (foldM)
import Random
import Data.Digest.SHA512 (hash)
import Data.Word
import Data.Bits
import Data.Binary
newtype Password = Password [Word8]
newtype Salt = Salt [Word8]
newtype HashedPass = HashedPass [Word8]
deriving Show
{- | A reasonable default for rsa pbkdf2? Actually I'm not really
sure, ask folk with more experience.
pbkdf2 = pbkdf2' prfSHA512 512 512 512
-}
t = pbkdf2 ( Password . toWord8s $ meh ) ( Salt . toWord8s $ moo )
pbkdf2 :: Password - Salt - HashedPass
pbkdf2 = pbkdf2' prfSHA512 512 512 512
{- | Password Based Key Derivation Function, from RSA labs.
pbkdf2' prf hlen cIters dklen (Password pass) (Salt salt)
-}
pbkdf2' :: ([Word8] - [Word8] - [Word8]) - Integer - Integer -
Integer - Password - Salt - HashedPass
pbkdf2' prf hlen cIters dklen (Password pass) (Salt salt)
| dklen ( (2^32-1) * hlen) = error $ pbkdf2, (dklen,hlen) : ++
(show (dklen,hlen))
| otherwise =
let --l,r :: Int
l = ceiling $ (fromIntegral dklen) / (fromIntegral hlen )
r = dklen - ( (l-1) * hlen)
ustream :: [Word8] - [Word8] - [[Word8]]
ustream p s = let x = prf p s
in x : ustream p x
--us :: Integer - [[Word8]]
us i = take (fromIntegral cIters) $ ustream pass ( salt `myor`
((intToFourWord8s i) ))
--f :: [Word8] - [Word8] - Integer - Integer - [Word8]
f pass salt cIters i = foldr1 myxor $ us i
ts :: [[Word8]]
ts = map (f pass salt cIters) ( [1..l] )
in HashedPass . take (fromIntegral dklen) . concat $ ts
-- The spec says
-- Here, INT (i) is a four-octet encoding of the integer i, most
significant octet first.
-- I'm reading from the right... is this the right thing?
toWord8s x = L.unpack . encode $ x
--intToFourWord8s :: Integer - [Word8]
intToFourWord8s i = let w8s = toWord8s $ i
in drop (length w8s -4) w8s
myxor :: [Word8] - [Word8] - [Word8]
myxor = zipWith xor
myor :: [Word8] - [Word8] - [Word8]
myor = zipWith (.|.)
prfSHA512 :: [Word8] - [Word8] - [Word8]
prfSHA512 x y = hash $ x ++ y
2008/11/26 John Meacham [EMAIL PROTECTED]:
What you are using there is not a salt, but rather a secret key. The
important thing about a salt is that it is different for _every user_.
and you actually store the salt unhashed along with the hash. (it is not
secret information). A salt protects against a dictionary attack, for
instance, you might have a dictionary of hash's and the common passwords
they go to but if you add a 32 bit salt, you would need 2^32 entries for
each dictionary word, making such an attack unworkable. You can also
trivially tell if two users have the _same_ password just by comparing
the hashes without a salt.
John
--
John Meacham - ⑆repetae.net⑆john⑈
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Re: [Haskell-cafe] haddock question [solved]
Ross Paterson wrote: On Thu, Nov 27, 2008 at 11:52:04AM +, allan wrote: I'm trying to locally build the documentation for the haskell-src-exts package and running into a bit of bother. If I run: cabal haddock I get the error: haddock: parse error in doc string The problem is that several of the modules (not Language.Haskell.Exts, but modules it imports) have headers containing a field Original that haddock doesn't recognize. a ha, Thank you, that has fixed the problem. regards allan -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] HaskellWiki image upload fails because of - probably - the filesize.
Hey dear Haskell-Cafe-Readers, I tried several times to upload several images - screenshots that is - to my HaskellWiki/Xmonad site: http://haskell.org/haskellwiki/Image:And1_xmonad.png I always get the error, that the connection to the site/server was reset. I mailed both administrators of the HaskellWiki but I got, for about 2-4 weeks now, no reply. I tried to upload the following images, maybe that's important: http://and1.donnergurgler.net/misc/screen_2008-09-26.png http://and1.donnergurgler.net/misc/screen_2008-11-02.png http://and1.donnergurgler.net/misc/screen_2008-11-10.png I was told, that the problem is maybe the filesize of the new images, because it is bigger, then the filesize of the image already uploaded. Thanks for reading this and hopefully finding the problem, -- Regards, Andi R. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] haddock question
On Thu, Nov 27, 2008 at 11:52:04AM +, allan wrote: I'm trying to locally build the documentation for the haskell-src-exts package and running into a bit of bother. If I run: cabal haddock I get the error: haddock: parse error in doc string The problem is that several of the modules (not Language.Haskell.Exts, but modules it imports) have headers containing a field Original that haddock doesn't recognize. Of course the lack of any location information in the error message is a deficiency in haddock. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Need machine for DPH benchmarking
On Thu, Nov 27, 2008 at 5:45 AM, Roman Leshchinskiy [EMAIL PROTECTED] wrote: Hi all, we, the DPH team, are at the moment in the very unfortunate situation of not having a proper machine for running our benchmarks on. Could a kind soul maybe give us (i.e., me) access to a quadcore or 2xquadcore x86 Linux or OS X machine? I only need to build ghc on it and run small benchmarks which never take more than a couple of minutes, maybe once every couple of days or so. We do need to use all cores, though, so no other CPU-intensive processes can be running during benchmarking. This is only for a week or two, until we get our own machine. We would be eternally grateful and won't forget you when DPH takes over the world. Another possibility is using the Amazon EC2 functionality and rent a high-CPU instance (http://aws.amazon.com/ec2/#instance) for as long as you need. An extra large high-CPU instance costs $0.80 per hour (http://aws.amazon.com/ec2/#pricing), is an 8-core machine, you only pay for the time used and it runs any kind of Linux you want (there are dozens of already configured instances with different configurations, it's also possible to configure your own). I've been using it for a few months and have no complaints. Roman Best regards, Daniel Yokomizo ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Proposal for associated type synonyms in Template Haskell
I've been away. I hope others will reply to this thread too; whatever you decide will end up in TH indefinitely. I know that Roman is interested in this. · You focus just on type families in class declarations (which is indeed where associated types started). But I suggest you also allow them at top level, as GHC does using the syntax type family T a :: * Indeed, since you propose to add to Dec, that'll happen automatically. But perhaps AssocTySynKindD is not a good name. Perhaps TySynFamilyD? · GHC uses type instance T [a] = Tree a as the way to add an equation to the definition of T. So perhaps TySynInstance rather than AssocTySynD? · I agree that it'd be good to do data type/newtype families at the same time. Roman needs this. · Your proposal for kinds looks fine. Simon From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of José Pedro Magalhães Sent: 11 November 2008 11:11 To: Haskell Cafe Subject: Re: [Haskell-cafe] Proposal for associated type synonyms in Template Haskell Hello Thomas, I see this is a proposal for a partial implementation of #1673 (http://hackage.haskell.org/trac/ghc/ticket/1673). Maybe it would be good if the remaining syntax (associated datatypes and type families) would also be defined and implemented in TH. Or maybe there isn't much demand for this?... Cheers, Pedro On Wed, Nov 5, 2008 at 15:57, Thomas van Noort [EMAIL PROTECTED]mailto:[EMAIL PROTECTED] wrote: Hello, Recently, we released a library on Hackage for generic rewriting (package rewriting if you are curious). The user of the library is expected to define type class instances to enable rewriting on his or her own datatypes. As these instances follow the datatype declarations closely, we tried to generate the instances using Template Haskell. Unfortunately, associated type synonyms are not yet supported by TH. After a presentation at the WGP'08, Simon encouraged us to write a proposal about adding associated type synonyms to TH, so that it can be added to GHC. So, here is our proposal. The TH AST must allow 1) kind declarations of associated type synonyms in class declarations and 2) their definitions in instance declarations. For example, class Foo a where type Bar a :: * instance Foo Int where type Bar Int = String The TH library defines a datatype Dec which contains a constructor for class declarations and instance declarations: data Dec = ... | ClassD Cxt Name [Name] [FunDep] [Dec] | InstanceD Cxt Type [Dec] ... 1) Associated type synonym kind declarations We suggest to add a constructor to the Dec type: ... | AssocTySynKindD Name [Name] (Maybe Kind) ... assocTySynKindD :: Name - [Name] - Maybe KindQ - DecQ The first field is the name of the associated type synonym, the second field is a list of type variables, and the third field is an optional kind. Since kinds are not yet defined in TH, we have to add some kind of kind definition (pun intended): data Kind = StarK | ArrowK Kind Kind type KindQ = Q Kind starK :: KindQ arrowK :: KindQ - KindQ - KindQ We explicitly choose not to reuse the Type type to define kinds (i.e., type Kind = Type as in GHC) since we think a separation between the two worlds is much clearer to the users of TH. 2) Associated type synonym definitions We suggest to add another constructor to the Dec type: ... | AssocTySynD Name [Type] Type ... assocTySynD :: Name - [TypeQ] - TypeQ - DecQ The first field is the name of the type synonym, the second field is a list of type arguments, and the third field is the body of the type synonym. We would like to hear your comments to this proposal. Regards, Thomas ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.orgmailto:Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: catting to cat gets stuck at 135K
Brandon S. Allbery KF8NH wrote: On 2008 Nov 10, at 19:04, Jason Dusek wrote: simple exe bytes args= do (i, o, e, p)- runInteractiveProcess exe args Nothing Nothing hPut i bytes s - hGetContents o hClose i return s Yep, that's your problem. forkIO the hPut. Maybe I didn't do enough here -- just wrapping in `forkIO` does not seem to actually help. *sigh* I hate the ghc runtime... it works in ghci, or compiled with -threaded. Would you hate it less if -threaded were the default? Otherwise you still get the deadlock because it only switches threads under limited circumstances (garbage collections?) No, the issue is that without real OS threads, a foreign call can't be pre-empted (pretty obvious when you think about it). waitForProcess ends up making a blocking foreign call - non-obvious, but at least it's documented. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [darcs-users] workarounds for Codec.Compression.Zlib errors in darcs
On Wed, Nov 26, 2008 at 14:38:33 +, Eric Kow wrote: In principle, the same advice applies for Windows users, with more details hopefully to follow on how the C libz in a GHC-accesible location. Details to follow. As promised, here are the details for installing darcs using our old internal binding to libz on Windows. Again, the instructions are either to cabal configure -f -external-zlib (Or to wait for darcs 2.1.2.3 to appear on hackage) Thanks to Salvatore Insalaco, our Windows Czar! -- There're two zlib versions for Windows: one compiled with ccall convention, and one with stdcall convention. We need the ccall one, at the address: http://gnuwin32.sourceforge.net/packages/zlib.htm The other one will *appear* to work, but darcs will segfault as soon as the first call to zlib is made. This is the step-by-step howto: 1) Download the binary from http://gnuwin32.sourceforge.net/downlinks/zlib-bin-zip.php and unzip it. 2) Copy the zlib1.dll file in bin directory in ghc's gcc-lib directory, and then rename it libz.dll. 3a) Copy the zlib1.dll file in c:\windows directory, WITHOUT renaming it. OR 3b) If you don't want to pollute your windows directory, just copy it in whatever directory is in the search PATH, or in the one you'll place darcs.exe binary. That's all. The cabal install will then just work. By the way: that's similar to the how-to for making curl work. Maybe we can update the windows building instructions providing a pre-install instructions to make cabal install darcs just work. -- Eric Kow http://www.nltg.brighton.ac.uk/home/Eric.Kow PGP Key ID: 08AC04F9 signature.asc Description: Digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Philip Wadler video on Howard-Curry Correspondence ???
On Wed, 26 Nov 2008 23:48:19 -0600, Galchin, Vasili [EMAIL PROTECTED] wrote: Hello, I am reading re-reading Prof. Wadler paper Proofs are Programs: 19th Century Logic and 21st Century Computing but also want to re-read watch his video on same subject. ??? There is a reference to the video in question at the following site, but the link seems to be broken: Proofs are Programs: 19th Century Logic and 21st Century Computing | Lambda the Ultimate http://lambda-the-ultimate.org/node/1447 The same link is also mentioned at the following site as well: Wadler: History of logic and programming languages http://homepages.inf.ed.ac.uk/wadler/topics/history.html The (broken) link mentioned at the above two sites is the following: TechNetCast Archives http://technetcast.ddj.com/tnc_catalog.html?item_id=1011 However, attempting to visit the above-mentioned site results in the following error message: Query Failed1 Since the same URL is mentioned at both sites, this error is unlikely to be the result of a typo. Perhaps either the item was removed, or the hosting server is down? You may wish to try reaching the contact person for the site hosting the video, Dr. Dobb's TechNetCast (see http://technetcast.ddj.com/), at [EMAIL PROTECTED] -- Benjamin L. Russell ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Fun with type functions
On Thu, Nov 27, 2008 at 9:29 AM, Simon Peyton-Jones [EMAIL PROTECTED] wrote: Friends GHC has embodied data type families since 6.8, and now type synonym families (aka type functions) in 6.10. However, apart from our initial papers there isn't much published material about how to *use* type families. But that hasn't stopped you: quite a few people are using them already, and of course there is a rich seam of work on using functional dependencies to express type-level computation. Ken Shan and Oleg Kiselyov and I are collaborating to write a paper for an upcoming workshop, under the general rubric of Fun with type functions (in homage to Thomas Hallgren's paper Fun with functional dependencies and Ralf Hinze's paper Fun with phantom types). So this message is to ask you: can you tell us about the most persuasive, fun application you've encountered, for type families or functional dependencies? Simple is good. It doesn't have to be elaborate: just something that does something useful you could not have done otherwise. Pointers to email threads are fine. Don't assume we already know about them (even if we participated in the thread :-) Part of what we're interested in is that *you* found the example compelling. Many thanks I documented, [1] and [2], my first encounter with functional dependencies. Maybe not a persuasive example, but I felt it was a fairly good introduction to them. /M [1]: http://therning.org/magnus/archives/354 [2]: http://therning.org/magnus/archives/355 -- Magnus Therning(OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Go Haskell!
Claus Reinke wrote: Do you have an example of a mutable state/ IO bound application, like, hmm, a window manager or a revision control system or a file system...? If you're looking for a challenge, how about this one (there used to be lots of Haskellers into this game, any of you still around?-): http://computer-go.org/pipermail/computer-go/2008-October/016680.html [ catching up with old haskell-cafe email ] Interestingly, I did this a while ago. Here's my results: $ ./Bench 1 10 b: 14840, w: 17143 mercy: 67982 elapsed time: 3.42s playouts/sec: 29208 so, nearly 30k/sec random playouts on 9x9. That's using a hack that stops the game when the score is heavily in favour of one player, it drops to around 20k/sec with that turned off. Not bad, but probably I'd guess an order of magnitude worse than you can do in tightly-coded C. The Haskell implementation isn't nice, as you predicted. Also the code is derived from some non-free internal MS code, so unfortunately I can't share it (but I could perhaps extract the free bits if anyone is really interested). W wins slightly more often I think because komi 5.5 on a 9x9 board is a tad high. It does parallelise too, of course: $ ./Bench 8 10 +RTS -N8 b: 14872, w: 17488 mercy: 67584 elapsed time: 1.00s playouts/sec: 99908 though still room for improvement there. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re[2]: [Haskell-cafe] Need machine for DPH benchmarking
Hello Daniel, Thursday, November 27, 2008, 4:43:08 PM, you wrote: Another possibility is using the Amazon EC2 functionality and rent a high-CPU instance (http://aws.amazon.com/ec2/#instance) for as long as these are virtual cores, which isn't appropriate for measuring performance on real 4/8 core boxes -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Possible issue with Hoogle and Haddock?
Hi Stephen, I've now worked around this bug in Hoogle - I'm just about to rebuild the website, and hopefully the bug will have disappeared. (Rebuilding the website could take a few days, as I'm currently hunting for the right compiler etc...) Thanks Neil On Fri, Nov 21, 2008 at 8:21 AM, Mitchell, Neil [EMAIL PROTECTED] wrote: I was noticing recently that there seems to be a problem with Hoogle and Haddock. In particular, I just hoogled bracket and got the following result: bracket :: IO a - a - IO b - a - IO c - IO c Clearly this is the wrong type, as it should be bracket :: IO a - (a - IO b) - (a - IO c) - IO c Is this a bug? Is is something that's well-known? Yes, it's a known bug: http://hackage.haskell.org/trac/ghc/ticket/2584 I can make a work around for Hoogle (well, I can write a workaround in the Hoogle specific code of Haddock), but was hoping that the bug would be fixed before 6.10. I guess its now worth making the Hoogle specific fix. Thanks Neil == Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html == ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] Need machine for DPH benchmarking
On Thu, Nov 27, 2008 at 12:25 PM, Bulat Ziganshin [EMAIL PROTECTED] wrote: Hello Daniel, Thursday, November 27, 2008, 4:43:08 PM, you wrote: Another possibility is using the Amazon EC2 functionality and rent a high-CPU instance (http://aws.amazon.com/ec2/#instance) for as long as these are virtual cores, which isn't appropriate for measuring performance on real 4/8 core boxes That's why I mentioned it as another possibility. It won't give you performance numbers for a specific processor but you can run tests to see parallelization behavior and get some food for thought. It's a pretty cheap way to explore ideas if you don't have a equivalent machine available. -- Best regards, Bulatmailto:[EMAIL PROTECTED] Best regards, Daniel Yokomizo ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Go Haskell!
Do you have an example of a mutable state/ IO bound application, like, hmm, a window manager or a revision control system or a file system...? If you're looking for a challenge, how about this one (there used to be lots of Haskellers into this game, any of you still around?-): http://computer-go.org/pipermail/computer-go/2008-October/016680.html Interestingly, I did this a while ago. Here's my results: $ ./Bench 1 10 b: 14840, w: 17143 mercy: 67982 elapsed time: 3.42s playouts/sec: 29208 so, nearly 30k/sec random playouts on 9x9. That's using a hack that stops the game when the score is heavily in favour of one player, it drops to around 20k/sec with that turned off. Nice!-) 20k playouts/sec (without the early cutoffs) is the rough number usually mentioned for these light playouts, reachable even in Java. My own Haskell code for that was a factor of 5 slower:-( Not bad, but probably I'd guess an order of magnitude worse than you can do in tightly-coded C. Yes, a few people have reported higher rates, but most hobby coders seem happy with 20k/sec - after that, it seems more interesting to move towards heavy playouts and combinations with tree-based search instead of light playouts with simple statistics alone. But if you don't get at least those 20k/sec, it is difficult to run the number of experiments needed to test presumed improvements in playing strength. The Haskell implementation isn't nice, as you predicted. What is really annoying for me is that I'm no longer used to this low-level style of coding, so every time I add something, performance goes down, and I have to work to get it back (I modified my playout code to match that reference bot specification - my bot does get the expected 50% wins against jrefbot, but is now a factor of 8 slower (still using only half the memory, though)). Not to mention that I'm throwing away many of the advantages of Haskell. That is one reason why I mentioned this challenge. Also the code is derived from some non-free internal MS code, so unfortunately I can't share it (but I could perhaps extract the free bits if anyone is really interested). Interesting, can you tell what kind of code those internal bits are? Of course, the fun is implementing it oneself, but it is very useful to have reference points, such as the refbot spec, or the Java implementation to play against. Your Haskell reference point will spur me to have another look at my bot's performance!-) The Go programming folks have a lot of useful infrastructure, btw, including a server just for bot-vs-bot competition: http://cgos.boardspace.net/ Not to mention monthly tournaments, competions, etc. It does parallelise too, of course: $ ./Bench 8 10 +RTS -N8 b: 14872, w: 17488 mercy: 67584 elapsed time: 1.00s playouts/sec: 99908 though still room for improvement there. That is the other reason why I mentioned this challenge: the specs people use for their competition bots are interestingly parallel. One example, this year's Computer Go Olympiad results: http://www.grappa.univ-lille3.fr/icga/tournament.php?id=181 Many Faces of Go, winner, currently maxes out at 32 cores, a limitation its author would like to remove (he's working with the Microsoft HPC group, btw). For the exhibition game against a pro that made the news this year, MoGo used a cluster of 800 cores: http://www.mail-archive.com/[EMAIL PROTECTED]/msg08692.html http://www.mail-archive.com/[EMAIL PROTECTED]/msg08710.html Of course, the simple reference bot implementations are a far cry from MoGo or ManyFaces, but I thought this would be an interesting non-trivial-but-doable challenge for Haskell performance and parallelism fans, especially since there are still many people interested in Go here;-) Claus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: catting to cat gets stuck at 135K
On 2008 Nov 27, at 8:51, Simon Marlow wrote: Brandon S. Allbery KF8NH wrote: On 2008 Nov 10, at 19:04, Jason Dusek wrote: simple exe bytes args= do (i, o, e, p)- runInteractiveProcess exe args Nothing Nothing hPut i bytes s - hGetContents o hClose i return s Yep, that's your problem. forkIO the hPut. Maybe I didn't do enough here -- just wrapping in `forkIO` does not seem to actually help. *sigh* I hate the ghc runtime... it works in ghci, or compiled with -threaded. Would you hate it less if -threaded were the default? Otherwise you still get the deadlock because it only switches threads under limited circumstances (garbage collections?) No, the issue is that without real OS threads, a foreign call can't be pre-empted (pretty obvious when you think about it). waitForProcess ends up making a blocking foreign call - non-obvious, but at least it's documented. The way this is usually handled in the non-threaded case is to either use SIGCHLD or non-blocking waitpid() so that green threads can continue running. I'm a little surprised this wasn't done. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] HaskellWiki image upload fails because of - probably - the filesize.
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 On Thu, Nov 27, 2008 at 8:11 AM, And1 wrote: Hey dear Haskell-Cafe-Readers, I tried several times to upload several images - screenshots that is - to my HaskellWiki/Xmonad site: http://haskell.org/haskellwiki/Image:And1_xmonad.png I always get the error, that the connection to the site/server was reset. I mailed both administrators of the HaskellWiki but I got, for about 2-4 weeks now, no reply. I tried to upload the following images, maybe that's important: http://and1.donnergurgler.net/misc/screen_2008-09-26.png http://and1.donnergurgler.net/misc/screen_2008-11-02.png http://and1.donnergurgler.net/misc/screen_2008-11-10.png I was told, that the problem is maybe the filesize of the new images, because it is bigger, then the filesize of the image already uploaded. Thanks for reading this and hopefully finding the problem, Size would not be the issue; I've uploaded multimegabyte tarballs in the past. I tried uploading one of your images and the connection fails immediately, so it looks to me also like there is a problem in the MediaWiki server. - -- gwern -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.9 (GNU/Linux) iEYEAREKAAYFAkku0bIACgkQvpDo5Pfl1oKSBACdF02Vmze2gi4CSJmjswxxEnmj orIAnRLzgng1xB6/urdCT4Kkb+e5Z0TR =tatY -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] workarounds for Codec.Compression.Zlib errors in darcs
On Wed, Nov 26, 2008 at 10:28:21PM +, Duncan Coutts wrote: On Wed, 2008-11-26 at 14:38 +, Eric Kow wrote: Older versions of darcs can to produce gzipped files with broken CRCs. We never noticed this because our homegrown wrapper around the C libz library does not pick up these errors. I should note that one moral of this story is to check that your FFI imports are correct. That is, check they import the foreign functions at the right Haskell types. In this case the mistake was that the foreign function returned a C int, but the Haskell foreign import declaration stated that the C function returned IO () rather than IO CInt. While that's true, Haskell also makes it easy to make the same sort of error with IO (or any other Monad) values, whether created with the FFI or not. If you say f = do x y z and y has type IO CInt then you won't get an error (and I don't think you can even ask for a warning with the current implementations). Should we have () :: (Monad m) = m () - m a - m a and force you to write _ - y ? Thanks Ian ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] workarounds for Codec.Compression.Zlib errors in darcs
On Thu, Nov 27, 2008 at 10:20 AM, Ian Lynagh [EMAIL PROTECTED] wrote: On Wed, Nov 26, 2008 at 10:28:21PM +, Duncan Coutts wrote: On Wed, 2008-11-26 at 14:38 +, Eric Kow wrote: Older versions of darcs can to produce gzipped files with broken CRCs. We never noticed this because our homegrown wrapper around the C libz library does not pick up these errors. I should note that one moral of this story is to check that your FFI imports are correct. That is, check they import the foreign functions at the right Haskell types. In this case the mistake was that the foreign function returned a C int, but the Haskell foreign import declaration stated that the C function returned IO () rather than IO CInt. While that's true, Haskell also makes it easy to make the same sort of error with IO (or any other Monad) values, whether created with the FFI or not. If you say f = do x y z and y has type IO CInt then you won't get an error (and I don't think you can even ask for a warning with the current implementations). Should we have () :: (Monad m) = m () - m a - m a and force you to write _ - y ? I'd like that (though I certainly didn't like that prospect when I started learning). I think the option of turning on a warning would be a nice happy medium. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] followedBy parser in Parsec
Hi,
Is there a way in Parsec to check what the next token is, and if it is what
you're hoping for, leave it there.
This is an example of something which doesn't work at all:
testpar = try $
do ae - array_element
option [] $ try $ satisfy (\c - c /= '(') unexpected
return ae
I'm finding this totally confusing by now %0 Can I invert notFollowedBy
somehow, or maybe there's a peek function I don't know about? Help!
Thanks,
Paul
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Re: [Haskell-cafe] Re: Go Haskell!
http://computer-go.org/pipermail/computer-go/2008-October/016680.html Interestingly, I did this a while ago. Here's my results: $ ./Bench 1 10 b: 14840, w: 17143 mercy: 67982 elapsed time: 3.42s playouts/sec: 29208 so, nearly 30k/sec random playouts on 9x9. That's using a hack that stops the game when the score is heavily in favour of one player, it drops to around 20k/sec with that turned off. Nice!-) 20k playouts/sec (without the early cutoffs) is the rough number usually mentioned for these light playouts, reachable even in Java. My own Haskell code for that was a factor of 5 slower:-( actually, that 5x is relative to jrefbot on my machine (Pentium M760, 2Ghz), which doesn't quite reach 20k/sec, so if your code would run at 20k/sec on my laptop, it would be 10x as fast as my bot:-(( Since you can't release your code, could you perhaps time the jrefbot from the url above on your machine as a reference point, so that I know how far I've yet to go? Something like: $ time ((echo genmove b;echo quit) | d:/Java/jre6/bin/java -jar refbots/javabot/jrefgo.jar 2) = E5 real0m2.539s user0m0.030s sys 0m0.031s Btw, I just realised where my bot dropped from 5x to 8x: to work around http://hackage.haskell.org/trac/ghc/ticket/2669 all my array accesses were wrapped in exception handlers, to get useful error messages while I adapted my code to the refbot spec.. That's not the only bug that got in the way: http://hackage.haskell.org/trac/ghc/ticket/2727 forced me to move from functional to imperative arrays much sooner than I wanted, and due to http://hackage.haskell.org/trac/ghc/ticket/1216 I did not even consider 2d arrays (the tuple allocations might have gotten in the way anyhow, but still..). What do those folks working on parallel Haskell arrays think about the sequential Haskell array baseline performance? Claus -- my slow bot's current time (for 20k playouts on a 2Ghz laptop): $ time ((echo genmove b;echo quit) | ./SimpleGo.exe 2) TEXT e5 - amaf-score: 0.127 TEXT e6 - amaf-score: 0.126 TEXT d5 - amaf-score: 0.126 TEXT f5 - amaf-score: 0.118 TEXT d6 - amaf-score: 0.116 TEXT f4 - amaf-score: 0.115 TEXT e7 - amaf-score: 0.115 TEXT f6 - amaf-score: 0.114 TEXT d4 - amaf-score: 0.110 TEXT d3 - amaf-score: 0.108 TEXT e5 - amaf-score: 0.127 = e5 = real0m10.711s user0m0.030s sys 0m0.031s ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Building QuickCheck 2 Under GHC 6.10.1
Having been a happy user of QuickCheck 2 for many years, I now find it won't build under ghc 6.10.1. Before I investigate further, has anyone encountered this problem and has a fix? Thanks, Dominic. C:\Users\Dom\QuickCheckSetup build Preprocessing library QuickCheck-2.0... Building QuickCheck-2.0... [2 of 9] Compiling Test.QuickCheck.Exception ( Test\QuickCheck\Exception.hs, dis t\build\Test\QuickCheck\Exception.o ) Test\QuickCheck\Exception.hs:12:31: Class `Exception' used as a type In the type `Exception' In the type `Either Exception a' In the type `IO (Either Exception a)' Test\QuickCheck\Exception.hs:15:36: Class `Exception' used as a type In the type `Exception' In the type `Either Exception a' In the type `IO (Either Exception a)' ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] followedBy parser in Parsec
Paul Keir wrote: Is there a way in Parsec to check what the next token is, and if it is what you're hoping for, leave it there. Maybe you're looking for 'lookAhead'? [...] //Stephan -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Go Haskell!
claus.reinke: http://computer-go.org/pipermail/computer-go/2008-October/016680.html Interestingly, I did this a while ago. Here's my results: $ ./Bench 1 10 b: 14840, w: 17143 mercy: 67982 elapsed time: 3.42s playouts/sec: 29208 so, nearly 30k/sec random playouts on 9x9. That's using a hack that stops the game when the score is heavily in favour of one player, it drops to around 20k/sec with that turned off. Nice!-) 20k playouts/sec (without the early cutoffs) is the rough number usually mentioned for these light playouts, reachable even in Java. My own Haskell code for that was a factor of 5 slower:-( actually, that 5x is relative to jrefbot on my machine (Pentium M760, 2Ghz), which doesn't quite reach 20k/sec, so if your code would run at 20k/sec on my laptop, it would be 10x as fast as my bot:-(( Since you can't release your code, could you perhaps time the jrefbot from the url above on your machine as a reference point, so that I know how far I've yet to go? Something like: $ time ((echo genmove b;echo quit) | d:/Java/jre6/bin/java -jar refbots/javabot/jrefgo.jar 2) = E5 real0m2.539s user0m0.030s sys 0m0.031s Btw, I just realised where my bot dropped from 5x to 8x: to work around http://hackage.haskell.org/trac/ghc/ticket/2669 all my array accesses were wrapped in exception handlers, to get useful error messages while I adapted my code to the refbot spec.. That's not the only bug that got in the way: http://hackage.haskell.org/trac/ghc/ticket/2727 forced me to move from functional to imperative arrays much sooner than I wanted, and due to http://hackage.haskell.org/trac/ghc/ticket/1216 I did not even consider 2d arrays (the tuple allocations might have gotten in the way anyhow, but still..). What do those folks working on parallel Haskell arrays think about the sequential Haskell array baseline performance? Try using a fast array library like uvector? (With no serious overhead for tuples too, fwiw)... -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Building QuickCheck 2 Under GHC 6.10.1
Indeed. The base3/base4 simultaneous install. http://haskell.org/haskellwiki/Upgrading_packages#runhaskell Two solutions: cabal install quickcheck (will determine the base dependency correct). or: runhaskell Setup.hs configure --constraint='base4' dominic.steinitz: Having been a happy user of QuickCheck 2 for many years, I now find it won't build under ghc 6.10.1. Before I investigate further, has anyone encountered this problem and has a fix? Thanks, Dominic. C:\Users\Dom\QuickCheckSetup build Preprocessing library QuickCheck-2.0... Building QuickCheck-2.0... [2 of 9] Compiling Test.QuickCheck.Exception ( Test\QuickCheck\Exception.hs, dis t\build\Test\QuickCheck\Exception.o ) Test\QuickCheck\Exception.hs:12:31: Class `Exception' used as a type In the type `Exception' In the type `Either Exception a' In the type `IO (Either Exception a)' Test\QuickCheck\Exception.hs:15:36: Class `Exception' used as a type In the type `Exception' In the type `Either Exception a' In the type `IO (Either Exception a)' ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Suggestion: Syntactic sugar for Maps!
bulat.ziganshin:
Hello circ,
Thursday, November 27, 2008, 9:59:08 PM, you wrote:
So why not {hello: 1, there: 2} ?
mymap hello:1 there:2
where mymap implementation is left to the reader :)
Hey, well, even easier:
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleInstances #-}
import Data.Map
import Data.String
import Text.JSON
instance IsString (Map Int Bool) where
fromString = fromList . read
-- or, say, JSON syntax for assoc lists.
{-
fromString s = case resultToEither (decode s) of
Right a - a
Left s - error s
-}
test :: Map Int Bool
test = [(7, True), (1, False)]
main = print test
-- Don
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Re: [Haskell-cafe] Re: Go Haskell!
What do those folks working on parallel Haskell arrays think about the sequential Haskell array baseline performance? Try using a fast array library like uvector? (With no serious overhead for tuples too, fwiw)... I downloaded uvector a while ago, but haven't got round to trying it (yet another array API?). Mostly, I'd like to know a little more than just fast array lib: - in which ways is it supposed to be faster? why? - for which usage patterns is it optimised? how? - if it is faster in general, why hasn't it replaced the default arrays? In general, I think Haskell has too many array libraries, with too many APIs. And that doesn't even take account the overuse of unsafe APIs, or the non-integrated type-level safety tricks - if array accesses were properly optimized, there should be a lot less need for the extreme all-or-nothing checks or home-grown alternative special-purpose APIs: - type-level code for watermarking indices belonging to certain index sets is one step to eliminate index checks, but hasn't been integrated into any of the standard libs - one could also associate index subsets with operations that do not leave the index superset belonging to an array (eg, if minimax, then min=i+-1=max, still safe without checks) - GHC does seem to common up index checks only if they are identical, but if minii+1i+2..i+jmax, only the outer checks are really necessary (as long as we know about '+') - whole-array ops allow to avoid index checks without type-level tricks, leaving the indexing implicit; but the corresponding ops in Data.Array.MArray claim to construct new arrays, contrary to the intended inplace updating for which one uses MArrays? - etc. etc. At least, uvector seems to take multi-element ops more seriously. But with so many people working on sequential and parallel Haskell array libraries, I was hoping for someone to take a big ax and clear out all that sick and half-dead wood, to give a small number of healthy arrays libs room to grow. Would be a lot easier for us poor naive Haskell array users who otherwise tend to get lost in that forrest!-) Just my 2c,-) Claus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] followedBy parser in Parsec
'lookAhead' is exactly what I needed: try $ array_element = \ae - lookAhead (reservedOp () return ae Many thanks, Paul Maybe you're looking for 'lookAhead'? [...] //Stephan -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Go Haskell!
Claus Reinke wrote: In general, I think Haskell has too many array libraries, with too many APIs. And that doesn't even take account the overuse of unsafe APIs, or the non-integrated type-level safety tricks - if array accesses were properly optimized, there should be a lot less need for the extreme all-or-nothing checks or home-grown alternative special-purpose APIs: - type-level code for watermarking indices belonging to certain index sets is one step to eliminate index checks, but hasn't been integrated into any of the standard libs - one could also associate index subsets with operations that do not leave the index superset belonging to an array (eg, if minimax, then min=i+-1=max, still safe without checks) - GHC does seem to common up index checks only if they are identical, but if minii+1i+2..i+jmax, only the outer checks are really necessary (as long as we know about '+') - whole-array ops allow to avoid index checks without type-level tricks, leaving the indexing implicit; but the corresponding ops in Data.Array.MArray claim to construct new arrays, contrary to the intended inplace updating for which one uses MArrays? - etc. etc. At least, uvector seems to take multi-element ops more seriously. But with so many people working on sequential and parallel Haskell array libraries, I was hoping for someone to take a big ax and clear out all that sick and half-dead wood, to give a small number of healthy arrays libs room to grow. Would be a lot easier for us poor naive Haskell array users who otherwise tend to get lost in that forrest!-) +3 The current array situation is unecessarily messy - and I prefer mathematical elegance to ad-hoc mess. (And you think I use Haskell, why exactly?) Of course, it's all very well complaining about it... somebody still has to *do* all this wonderful stuff. :-/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Go Haskell!
On Thu, Nov 27, 2008 at 1:20 PM, Claus Reinke [EMAIL PROTECTED]wrote: What do those folks working on parallel Haskell arrays think about the sequential Haskell array baseline performance? Try using a fast array library like uvector? (With no serious overhead for tuples too, fwiw)... I downloaded uvector a while ago, but haven't got round to trying it (yet another array API?). Mostly, I'd like to know a little more than just fast array lib: - in which ways is it supposed to be faster? why? - for which usage patterns is it optimised? how? - if it is faster in general, why hasn't it replaced the default arrays? In general, I think Haskell has too many array libraries, with too many APIs. And that doesn't even take account the overuse of unsafe APIs, or the non-integrated type-level safety tricks - if array accesses were properly optimized, there should be a lot less need for the extreme all-or-nothing checks or home-grown alternative special-purpose APIs: - type-level code for watermarking indices belonging to certain index sets is one step to eliminate index checks, but hasn't been integrated into any of the standard libs - one could also associate index subsets with operations that do not leave the index superset belonging to an array (eg, if minimax, then min=i+-1=max, still safe without checks) - GHC does seem to common up index checks only if they are identical, but if minii+1i+2..i+jmax, only the outer checks are really necessary (as long as we know about '+') - whole-array ops allow to avoid index checks without type-level tricks, leaving the indexing implicit; but the corresponding ops in Data.Array.MArray claim to construct new arrays, contrary to the intended inplace updating for which one uses MArrays? - etc. etc. This library would satisfy most of your requirements I suspect: http://ofb.net/~frederik/vectro/draft-r2.pdf My understanding is that the author's code could be turned into a real library fairly easily if it hasn't been already. I only read the paper; I didn't go looking for the library on hackage, but the author does provide the code for the library. The author also says their Haskell code is faster than the same algorithm in Matlab. But, I have to say. Whenever you're faking dependent types in Haskell things get harder to understand for the programmer. Checkout the section in the above paper about type checking. Dependent types, even simulated ones, come with lots of cool static guarantees but understanding how to program with them comes with a high barrier to entry. I think this cognitive load is even higher in Haskell where dependent types have to simulated by doing seemingly bizarre things. I think it is this usability aspect that prevents the techniques from becoming more common in Haskell. At least, uvector seems to take multi-element ops more seriously. But with so many people working on sequential and parallel Haskell array libraries, I was hoping for someone to take a big ax and clear out all that sick and half-dead wood, to give a small number of healthy arrays libs room to grow. Would be a lot easier for us poor naive Haskell array users who otherwise tend to get lost in that forrest!-) Sometimes a good library design is an evolutionary process. Maybe it's time to apply a fitness function. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Fun with type functions
On Thu, Nov 27, 2008 at 8:29 PM, Simon Peyton-Jones [EMAIL PROTECTED] wrote: So this message is to ask you: can you tell us about the most persuasive, fun application you've encountered, for type families or functional dependencies? I only just discovered functional dependencies a week or two ago, and when it solved my problem it absolutely made my day. I was reading 'Bananas, Lenses, etc.' and wanted to implement paramorphic recursion with a type class. My initial attempt: class Paramorphic p where term :: p - Bool this :: p - a next ::: p - p para :: (Paramorphic p) = t - (a - (p, t) - t) -p - t para a f p | term p = a | otherwise = f (this p) (next p, para a f (next p)) instance Paramorphic Int where term = (== 0) this = id next = subtract 1 This is broken, since 'a' in 'this' is loose. Then I found multiple class parameters: class Paramorphic p a where ... But 'a' was still too loose--para's type became para :: (Paramorphic p a, Paramorphic p a1, Paramorphic p a2, Paramorphic p a3) = t - (a1 - (p, t) - t) - p - t But a fundep solved it for me: class Paramorphic p a | p - a where ... I could now pretty much do factorial and tails from the paper. fact = para 1 (\a (_, b) - a * b) instance Paramorphic [a] a where term = null this = head next = tail tails = para [[]] (\a (as, b) - (a : as) : b) Not exactly a 'fun' example, but I was smiling for hours after discovering this. :) Toby. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Suggestion: Syntactic sugar for Maps!
In all fairness, this basically forces you to say trust me to the compiler for something that should be verifiable statically. A typo results in a runtime error -- in a way, this is worse than Perl. Quasi-quotes are really the right answer but hardly simple in this case... -- _jsn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Shared modification inside lambdas
I'm developing an embedded DSL in Haskell (for exact real arithmetic work, but that's irrelevant right now.) Among other things, the language contains functions and application, as well as various terms. In one iteration, the abstract syntax looked kinda like this (in spirit, don't worry about the actually available terms...) data Expr = Var String | Const Int | Plus Expr Expr | Quantified Range String Expr | Lambda String Expr | App Expr Expr Here, lambda-terms just have the name of their bound variable and the RHS. Quantified terms are much like specialized lambdas; one note is that you *will* have to evaluate the RHS of the quantified term with many values for the argument. It's obvious how to write an evaluator on these--just keep an environment, etc. All well and good, but it seems to me that if I'm embedding the DSl, shouldn't I be able to use the host language's facilities--for example, function abstractions and applications--directly? Well, I tried this, and it seems it works OK, like so: data Expr = Var String | Const Int | Plus Expr Expr | Quantified Range (Int - Expr) I replaced Lambda terms and applications with Haskell-level functions. Note that my quantifiers still need internal functions, but I replaced them in the same fashion. However, I have a problem; one thing I often have to do with expressions is refine them, where refine has type: refine :: Expr - Expr and transforms expressions into more interesting ones via certain, mostly simple rules. The problem comes with functions, either just plain lambdas or quantified ones. The rule for refining functions boils down to just refining (recursively) the RHS; in the old version, that was easy! refine (Lambda var rhs) = Lambda var (refine rhs) I only refine while evaluating terms of type Expr, so top level functions aren't important--by the time I'm evaluating them, I've applied them to arguments--but quantified terms are a problem. I could write something like: refine (Quantified range pred) = Quantified range pred' where pred' = \c - refine (pred c) But the problem is that this refines the term, again, every time I apply an argument to pred': I know I'm going to apply arguments many times to that new pred, and I want to refine it /once/: refinement is argument-agnostic, it only rearranges the structure of the AST, so in theory it'd be nice if I could refine that structure, just duplicating references to the appropriate free variable where I would have duplicated refences to the appropriate (Var String) before. Am I sore out of luck here? Is there a reasonable way I can implement my internal functions via Haskell functions, but apply argument-agnostic transformations to the RHS in a shared fashion? Or, is there some optimization in GHC that means I don't need to worry about this? Thanks, AHH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Fun with type functions
My work on lightweight session types (modeled after this year's ICFP paper on the same subject) used type and data families extensively for an elegant way of connecting communicating coroutines: Empty types are used for sessions: data Eps -- empty session data a :?: s -- read an a followed by session s data a :!: s -- write an a followed by session s -- etc. These have kind *, which makes them easy to use in other type-level code; my first formulation had the session types as functors directly, but that led to needing kind signatures elsewhere and made working with these types much more difficult.. Type families are used to represent the dual of a session; that is, a session that reads an Int can connect with a session that writes an Int. type family Dual s type instance Dual Eps = Eps type instance Dual (a :?: s) = a :!: Dual s type instance Dual (a :!: s) = a :?: Dual s -- etc. Then data families give structure to the session: data family Rep s a newtype instance Rep Eps a = Done a data instance Rep (x :!: s) a = Send x (Rep s a) newtype instance Rep (x :?: s) a = Receive (x - Rep s a) -- etc. Rep s converts a sessions (kind *) into a functor (kind * - *). It also allows easy experimentation with alternate formulations of the problem that potentially have different kinds. Finally, a typeclass allows interpretation of these types, connecting two sessions together to run as coroutines: class Coroutine s where connect :: (Dual s ~ c, Dual c ~ s) = Rep s a - Rep c b - (a,b) instance Coroutine Eps where connect (Done a) (Done b) = (a,b) instance Coroutine s = Coroutine (x :!: s) where connect (Send x s) (Receive k) = connect s (k x) instance Coroutine s = Coroutine (x :?: s) where connect (Receive k) (Send x c) = connect (k x) c The proof that two routines can safely connect is done entirely at compile time; the connection routine just takes care of routing data between the two processes. -- ryan On Thu, Nov 27, 2008 at 1:29 AM, Simon Peyton-Jones [EMAIL PROTECTED] wrote: Friends GHC has embodied data type families since 6.8, and now type synonym families (aka type functions) in 6.10. However, apart from our initial papers there isn't much published material about how to *use* type families. But that hasn't stopped you: quite a few people are using them already, and of course there is a rich seam of work on using functional dependencies to express type-level computation. Ken Shan and Oleg Kiselyov and I are collaborating to write a paper for an upcoming workshop, under the general rubric of Fun with type functions (in homage to Thomas Hallgren's paper Fun with functional dependencies and Ralf Hinze's paper Fun with phantom types). So this message is to ask you: can you tell us about the most persuasive, fun application you've encountered, for type families or functional dependencies? Simple is good. It doesn't have to be elaborate: just something that does something useful you could not have done otherwise. Pointers to email threads are fine. Don't assume we already know about them (even if we participated in the thread :-) Part of what we're interested in is that *you* found the example compelling. Many thanks Simon, Ken, Oleg PS: I'm broadcasting this message to GHC-users and Haskell-cafe, but to avoid deluging ghc-users, please reply just to us and Haskell cafe. (Interested ghc-users can follow the threads there from the archives if they want.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Need machine for DPH benchmarking
Hi again, a big thank you to all the people who offered us machines. I think we should be fine now. World domination is just around the corner! Roman On 27/11/2008, at 18:45, Roman Leshchinskiy wrote: Hi all, we, the DPH team, are at the moment in the very unfortunate situation of not having a proper machine for running our benchmarks on. Could a kind soul maybe give us (i.e., me) access to a quadcore or 2xquadcore x86 Linux or OS X machine? I only need to build ghc on it and run small benchmarks which never take more than a couple of minutes, maybe once every couple of days or so. We do need to use all cores, though, so no other CPU-intensive processes can be running during benchmarking. This is only for a week or two, until we get our own machine. We would be eternally grateful and won't forget you when DPH takes over the world. Roman ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Go Haskell!
Claus Reinke: What do those folks working on parallel Haskell arrays think about the sequential Haskell array baseline performance? You won't like the answer. We are not happy with the existing array infrastructure and hence have our own. Roman recently extracted some of it as a standalone package: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/vector In the longer run, we would like to factor our library into DPH- specific code and general-purpose array library that you can use independent of DPH. Manuel ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] I have forgotten .. ghci question
Hello, I have an experimental version of a package ~/FTP/Haskell/blah. Who I point ghci ath this experimental package version so I can poke around? Kind regards, Vasili ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANNOUNCE: Haskell Communities and Activities Report (15th ed., November 2008)
On behalf of the many, many contributors, I am pleased to announce that the Haskell Communities and Activities Report (15th edition, November 2008) http://www.haskell.org/communities/ is now available from the Haskell Communities home page in PDF and HTML formats. Many thanks go to all the people that contributed to this report, both directly, by sending in descriptions, and indirectly, by doing all the interesting things that are reported. I hope you will find it as interesting a read as I did. If you have not encountered the Haskell Communities and Activities Reports before, you may like to know that the first of these reports was published in November 2001. Their goal is to improve the communication between the increasingly diverse groups, projects, and individuals working on, with, or inspired by Haskell. The idea behind these reports is simple: Every six months, a call goes out to all of you enjoying Haskell to contribute brief summaries of your own area of work. Many of you respond (eagerly, unprompted, and sometimes in time for the actual deadline ;-) to the call. The editor collects all the contributions into a single report and feeds that back to the community. When I try for the next update, six months from now, you might want to report on your own work, project, research area or group as well. So, please put the following into your diaries now: End of April 2009: target deadline for contributions to the May 2009 edition of the HCA Report Unfortunately, many Haskellers working on interesting projects are so busy with their work that they seem to have lost the time to follow the Haskell related mailing lists and newsgroups, and have trouble even finding time to report on their work. If you are a member, user or friend of a project so burdened, please find someone willing to make time to report and ask them to register with the editor for a simple e-mail reminder in April (you could point me to them as well, and I can then politely ask if they want to contribute, but it might work better if you do the initial asking). Of course, they will still have to find the ten to fifteen minutes to draw up their report, but maybe we can increase our coverage of all that is going on in the community. Feel free to circulate this announcement further in order to reach people who might otherwise not see it. Enjoy! Janis Voigtlaender hcar at haskell.org -- Dr. Janis Voigtlaender http://wwwtcs.inf.tu-dresden.de/~voigt/ mailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Suggestion: Syntactic sugar for Maps!
Don Stewart wrote:
bulat.ziganshin:
Hello circ,
Thursday, November 27, 2008, 9:59:08 PM, you wrote:
So why not {hello: 1, there: 2} ?
mymap hello:1 there:2
where mymap implementation is left to the reader :)
I can't see the context of the beginning of this thread, but I've always
found:
fromList [(hello,1),(there,2)]
to be a relatively simple syntax, and still checked at compile time.
Anonymous sum + product types plus lists are a pretty good approximation
for lots of concrete syntax, and they're type checks.
(Anonymous sum, Either, is slightly more syntactically heavy than you'd
like, though...)
Jules
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Re: [Haskell-cafe] Re: Suggestion: Syntactic sugar for Maps!
On Fri, Nov 28, 2008 at 12:04 AM, Jules Bean [EMAIL PROTECTED] wrote: I can't see the context of the beginning of this thread, but I've always found: fromList [(hello,1),(there,2)] to be a relatively simple syntax, and still checked at compile time. I never liked that. Too much syntax overhead. But this clears it right up: foo = fromList [ hello : 1, there : 2 ] where (:) = (,) And also I haven't been following the thread, so this may not be any kind of answer. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
