Re: [Haskell-cafe] Re: Images and GUIs in Haskell
Quoth Achim Schneider on Sun, Jun 01, 2008 at 04:09:10 +0200 I would go for GL(U(T)), as it's as good for 2d primitives as SDL will ever be, has excellent cross-platform support and allows you to go 3d if you want to. There's also some very decent event handling. You can use R as well. http://www.r-project.org/ -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpUxe2kMb6IX.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GHCi panic
Andrew Coppin wrote: I don't suppose this will surprise anybody greatly, but... Apparently if you write a Haskell module that is 400 KB in size and defines a single CAF consisting of a 45,000-element [String], GHCi panics when attempting to load it interpretted, and hits a stack overflow attempting to load it compiled. qv http://hackage.haskell.org/trac/ghc/ticket/2002 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: hmatrix
Anatoly Yakovenko wrote: do you have any plans to provide an interface for inplace updates? Yes, I will try to write a simple version of Data.Array.ST... On Sun, Jun 1, 2008 at 3:20 AM, Alberto Ruiz [EMAIL PROTECTED] wrote: Anatoly Yakovenko wrote: What is the most efficient way to update a position in a matrix or a vector? I came up with this: updateVector :: Vector Double - Int - Double - Vector Double updateVector vec pos val = vec `add` v2 where v2 = fromList $ (replicate (pos) 0.0) ++ ((val - (vec @ pos)):(replicate ((dim vec)- pos - 1) 0.0)) but this seems pretty inefficient to me. thanks, Anatoly It is probably more efficient to use subVector and join (implemented by copyArray): updateVector' v pos val | pos == 0= join [b,c] | pos == dim v -1 = join [a,b] | otherwise = join [a,b,c] where a = subVector 0 pos v b = fromList [val] c = subVector (pos+1) (dim v -pos-1) v updateVector' (fromList [1,2,3,4,5]) 2 57 5 | [1.0,2.0,57.0,4.0,5.0] (The three cases are required because empty vectors are not currently allowed.) Something similar can be done for matrices using flatten and reshape. Although vectors and matrices in this library are immutable and intended to be manipulated as a whole by higher level functions, this kind of update functions may often be useful. I will include them soon. Alberto ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [ANNOUNCE] git-darcs-import 0.1
On 1 jun 2008, at 20.44, Bertram Felgenhauer wrote: Hi, I'm pleased to announce yet another tool for importing darcs repositories to git. Unlike darcs2git [1] and darcs-to-git [2], it's written in Haskell, on top of the darcs2 source code. The result is a much faster program - it can convert the complete ghc 6.9 branch (without libraries) in less than 15 minutes on my slightly dated machine (Athlon XP 2500 +), which is quite fast [3]. Incremental updates work, too. Nice! Do you happen to also have a darcs (or Git) repository somewhere? / Thomas -- Monkey killing monkey killing monkey over pieces of the ground. Silly monkeys give them thumbs they forge a blade And where there's one they're bound to divide it Right in two PGP.sig Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ghc 6.8.2 issue
On Mon, 2008-06-02 at 00:07 -0500, Galchin, Vasili wrote: Hello, I have been developing new code for the unix package. I have run into what I think are ghc 6.8.2 anomalies but couldn't see a pattern. Possibly now I do. I have been using the 32-bit x86 ghc binary that I downloaded from http://www.haskell.org and running on Ubuntu Linux. I am pretty I can repeat now. Everything is ok until I do sudo runhaskell Setup.hs install which installs a new unix package that I just built. Of course the intall installs into /usr/local/lib/unix-2.3.0.0/ghc-6.8.2. The install seems to destroy some ghc compiler state under /usr/local ... That sounds right. You're replacing the unix-2.3.0.0 library that comes with ghc-6.8.2 with your own version. It is highly unlikely to be ABI compatible with the one you are replacing and so all the other packages that already depends on the existing unix-2.3.0.0 library end up broken. You'd expect this kind of breakage to be exposed as link errors and segfaults. I suggest you do not replace any of the libraries that come with ghc. To be more precise, it is perfectly ok to *add new versions* but it is not ok to *replace existing versions* without rebuilding all the other libs that depend on it. Make sense? So if you really want to make changes to the unix lib, make sure you change the version number too. I also suggest not installing the packages as root, just install them locally. That way you can guarantee you never mess up your ghc install. You would be able to revert to a clean ghc install just by removing your ~/.ghc/$arch/ghc-6.8.2/package.conf file which will unregister *all* locally registered packages. To unregister individual packages use ghc-pkg --user unregister $pkgname Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [ANNOUNCE] git-darcs-import 0.1
Thomas Schilling wrote: On 1 jun 2008, at 20.44, Bertram Felgenhauer wrote: [git-darcs-import] Nice! Do you happen to also have a darcs (or Git) repository somewhere? I've uploaded my (git) repo to repo.or.cz, see http://repo.or.cz/w/git-darcs-import.git Patches are welcome. enjoy, Bertram ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] hs-plugins compile error
Hi, I'm getting the compilation error that is actually logged on Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/plugins Below is a small diff file that resolves these problems; I don't know what the proper protocol is for submitting these diffs but it may be useful to someone. - E diff -ur plugins-1.2-orig/src/System/Plugins/Env.hs plugins-1.2/src/System/Plugins/Env.hs --- plugins-1.2-orig/src/System/Plugins/Env.hs 2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/Env.hs 2008-06-02 15:00:25.0 +0100 @@ -73,7 +73,7 @@ import Control.Concurrent.MVar ( MVar(), newMVar, withMVar ) -import Distribution.Package +import Distribution.Package hiding (packageName) import Text.ParserCombinators.ReadP import qualified Data.Map as M diff -ur plugins-1.2-orig/src/System/Plugins/PackageAPI.hs plugins-1.2/src/System/Plugins/PackageAPI.hs --- plugins-1.2-orig/src/System/Plugins/PackageAPI.hs 2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/PackageAPI.hs2008-06-02 14:59:49.0 +0100 @@ -40,7 +40,7 @@ #if CABAL == 1 || __GLASGOW_HASKELL__ = 604 import Distribution.InstalledPackageInfo -import Distribution.Package +import Distribution.Package hiding (depends, packageName) #else import System.Plugins.Package #endif diff -ur plugins-1.2-orig/src/System/Plugins/ParsePkgConfCabal.hs plugins-1.2/src/System/Plugins/ParsePkgConfCabal.hs --- plugins-1.2-orig/src/System/Plugins/ParsePkgConfCabal.hs2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/ParsePkgConfCabal.hs 2008-06-02 14:58:56.0 +0100 @@ -6,7 +6,7 @@ ) where import Distribution.InstalledPackageInfo -import Distribution.Package +import Distribution.Package hiding (depends) import Distribution.Version import Data.Char ( isSpace, isAlpha, isAlphaNum, isUpper, isDigit ) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Mutually Recursive Modules
Hello
I'm using GHC 6.8.2 with mutally recursive modules. I'm familiar with
how to do simple cases in GHC ({-# SOURCE #-} and .hs-boot files) but I
can't figure out how to get it to work for a particular set of modules.
Is it known (i.e., proven) that GHC 6.8.2 can compile any set of
mutually recursive modules without refactoring? Are there known
limitations?
Thanks,
Richard G.
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Re: [Haskell-cafe] Mutually Recursive Modules
Richard Giraud wrote:
Hello
I'm using GHC 6.8.2 with mutally recursive modules. I'm familiar with
how to do simple cases in GHC ({-# SOURCE #-} and .hs-boot files) but I
can't figure out how to get it to work for a particular set of modules.
Is it known (i.e., proven) that GHC 6.8.2 can compile any set of
mutually recursive modules without refactoring? Are there known
limitations?
With the old (6.2 and before) .hi-boot scheme where there was no
abstraction in boot-files, it could probably do anything that it could
do. But I'm not convinced with .hs-boot... it can resolve one level of
cycle, and I don't know how to *prove* that it *can't* do any given
thing, but I strongly suspect there are things it can't do. Luckily, it
is very often the case that your code will be better off anyway if
refactored to have less module recursion. (though not always.)
-Isaac
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Re: [Haskell-cafe] Re: Damnit, we need a CPAN.
Am Freitag, 30. Mai 2008 22:09 schrieb Achim Schneider: […] I'm generally very interested in declarative GUI programming, but not nearly enough acquainted with the whole topic to judge one project's approach over the other. I just followed standard scientific evaluation technique to select the projects to consider: The ones with the most and most recent activity win. So far, my impression is that documentation is severely lacking, but then I'm too busy watching Babylon 5 right now and did not get more than half an hour or so looking at grapefruit. Okay, I think we’ll improve API documentation and then make a release, despite Grapefruit not being production quality yet. I hope, you’ll find it useful. :-) Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] What is the maturity of Haskell Web Frameworks
I am building a web-app that, in broad strokes, allows a leader to assign tasks to team members and allows team members to accept/reject/pick tasks that they want to do. I really like Haskell and I would like to use it to implement the solution. Are frameworks like Happs ready? Not so much in terms of documentation, but in functionality and stability. -Deech _ Give to a good cause with every e-mail. Join the i’m Initiative from Microsoft. http://im.live.com/Messenger/IM/Join/Default.aspx?souce=EML_WL_ GoodCause___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Default definitions for associated type synonyms
Isaac, Does anyone know if it is possible to specify a default definition for an associated type synonym? According to http://hackage.haskell.org/trac/ghc/wiki/TypeFunctionsStatus defaults for associated types is still a TODO. Cheers, Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Default definitions for associated type synonyms
Dreixel wrote: Hello, Does anyone know if it is possible to specify a default definition for an associated type synonym? When I tried: class A a where type B a = a GHC (version 6.9.20080309) told me: Type declaration in a class must be a kind signature or synonym default. However, when I look at the parser I see no way to specify such synonym default. Is this possible? I'm curious... so, cc'ing glasgow-haskell-users mailinglist because the question is more likely to be noticed by relevant people there. Thanks, Zé Pedro ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What is the maturity of Haskell Web Frameworks
On Mon, Jun 02, 2008 at 09:37:11AM -0500, Aditya Siram wrote: I am building a web-app that, in broad strokes, allows a leader to assign tasks to team members and allows team members to accept/reject/pick tasks that they want to do. I really like Haskell and I would like to use it to implement the solution. Are frameworks like Happs ready? Not so much in terms of documentation, but in functionality and stability. Me too, but in this case if it's only about assigning tasks you should consider using existing solutions such as flysrpay or mantis http://www.mantisbt.org/ Maybe they fit your needs ? mit freundlichem Gruss Marc Weber ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: cabal install fail for happs-hsp-template
I just noticed this is also reported as a 6.8 build failure on hackage itself. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/happs-hsp-template 2008/6/2 Thomas Hartman [EMAIL PROTECTED]: Can cabal install be made to work for this package? * [EMAIL PROTECTED]:~sudo cabal install happs-hsp-template [sudo] password for thartman: cabal: internal error: could not construct a valid install plan. The proposed (invalid) plan contained the following problems: Package Cabal is required by several packages, but they require inconsistent versions: package ghc-6.8.2 requires Cabal-1.2.3.0 package plugins-1.2 requires Cabal-1.5.2 [EMAIL PROTECTED]:~cabal --version cabal-install version 0.4.7 using version 1.3.11 of the Cabal library [EMAIL PROTECTED]:~ghc --version The Glorious Glasgow Haskell Compilation System, version 6.8.2 [EMAIL PROTECTED]:~ghc-pkg list | grep -i ghc /usr/local/lib/ghc-6.8.2/package.conf: (ghc-6.8.2), haskell-src-1.0.1.1, haskell98-1.0.1.0, hpc-0.5.0.0, ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: hmatrix
do you have any plans to provide an interface for inplace updates? Yes, I will try to write a simple version of Data.Array.ST... I can try to help you, although I still dont quite grok monads. Wouldn't it be more efficient to use StorableArray, so you can cast from and to C? I am not sure how vectors and matrixes are represented in C, but I imagine it should be possible to manipulate them without resorting to copying between haskell and C. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] cabal install fail for happs-hsp-template
Can cabal install be made to work for this package? * [EMAIL PROTECTED]:~sudo cabal install happs-hsp-template [sudo] password for thartman: cabal: internal error: could not construct a valid install plan. The proposed (invalid) plan contained the following problems: Package Cabal is required by several packages, but they require inconsistent versions: package ghc-6.8.2 requires Cabal-1.2.3.0 package plugins-1.2 requires Cabal-1.5.2 [EMAIL PROTECTED]:~cabal --version cabal-install version 0.4.7 using version 1.3.11 of the Cabal library [EMAIL PROTECTED]:~ghc --version The Glorious Glasgow Haskell Compilation System, version 6.8.2 [EMAIL PROTECTED]:~ghc-pkg list | grep -i ghc /usr/local/lib/ghc-6.8.2/package.conf: (ghc-6.8.2), haskell-src-1.0.1.1, haskell98-1.0.1.0, hpc-0.5.0.0, ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Damnit, we need a CPAN.
On 29 maj 2008, at 18.13, Don Stewart wrote: Hackage and Cabal are nice, but a command line tool for automatically searching Hackage and installing Hackage packages (like the cpan program, or easy_install) would be nice. Unless I haven't done my homework and this tool exists... This tool exists. It is called 'cabal-install'. To try out one of today's new packages: $ cabal update $ cabal install category-extras Another nice feature: Say you want to hack on the darcs version of a project, but you need to install the dependencies. If the project is Cabalised you can build and install the darcs version as well as all dependencies by calling 'cabal install' with no arguments inside the project directory. $ darcs get project $ cd project $ cabal install / Thomas -- Push the envelope. Watch it bend. PGP.sig Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What is the maturity of Haskell Web Frameworks
aditya_siram: I am building a web-app that, in broad strokes, allows a leader to assign tasks to team members and allows team members to accept/reject/pick tasks that they want to do. I really like Haskell and I would like to use it to implement the solution. Are frameworks like Happs ready? Not so much in terms of documentation, but in functionality and stability. HAppS is nice (see hpaste.org for example, which is nice and simple, and has been running for over a year). Another nice option in Haskell is using something like HStringTemplate or the xhtml combinators with fastcgi hooked into GHC's concurrency mechanisms. You can find *many* more things here, http://hackage.haskell.org/packages/archive/pkg-list.html#cat:Network http://hackage.haskell.org/packages/archive/pkg-list.html#cat:Web ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] hs-plugins compile error
Thanks, if possible, could you construct this as a patch against the darcs branch, which lives here: http://code.haskell.org/~dons/code/hs-plugins Cheers, Don devriese: Hi, I'm getting the compilation error that is actually logged on Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/plugins Below is a small diff file that resolves these problems; I don't know what the proper protocol is for submitting these diffs but it may be useful to someone. - E diff -ur plugins-1.2-orig/src/System/Plugins/Env.hs plugins-1.2/src/System/Plugins/Env.hs --- plugins-1.2-orig/src/System/Plugins/Env.hs2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/Env.hs 2008-06-02 15:00:25.0 +0100 @@ -73,7 +73,7 @@ import Control.Concurrent.MVar ( MVar(), newMVar, withMVar ) -import Distribution.Package +import Distribution.Package hiding (packageName) import Text.ParserCombinators.ReadP import qualified Data.Map as M diff -ur plugins-1.2-orig/src/System/Plugins/PackageAPI.hs plugins-1.2/src/System/Plugins/PackageAPI.hs --- plugins-1.2-orig/src/System/Plugins/PackageAPI.hs 2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/PackageAPI.hs 2008-06-02 14:59:49.0 +0100 @@ -40,7 +40,7 @@ #if CABAL == 1 || __GLASGOW_HASKELL__ = 604 import Distribution.InstalledPackageInfo -import Distribution.Package +import Distribution.Package hiding (depends, packageName) #else import System.Plugins.Package #endif diff -ur plugins-1.2-orig/src/System/Plugins/ParsePkgConfCabal.hs plugins-1.2/src/System/Plugins/ParsePkgConfCabal.hs --- plugins-1.2-orig/src/System/Plugins/ParsePkgConfCabal.hs 2008-06-02 14:57:59.0 +0100 +++ plugins-1.2/src/System/Plugins/ParsePkgConfCabal.hs 2008-06-02 14:58:56.0 +0100 @@ -6,7 +6,7 @@ ) where import Distribution.InstalledPackageInfo -import Distribution.Package +import Distribution.Package hiding (depends) import Distribution.Version import Data.Char ( isSpace, isAlpha, isAlphaNum, isUpper, isDigit ) ___ 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: hmatrix
Hello Anatoly, Yes, I will try to write a simple version of Data.Array.ST... Wouldn't it be more efficient to use StorableArray, so you can cast there is some difference between them - MutableByteArray# (used for STUArray) is movable Haskell object which is subject to GC while StorableArray has a fixed address and allocated through C malloc(). this makes MBA more appropriate for small arrays while SA should be used for large ones because GC makes memory usage of program 3 times larger -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: modelling C in Haskell ..
Galchin, Vasili wrote: my knowledge of point-free is from category theory. in what sense is Haskell point-free handle namespace pollution? In the sense that you can write e.g. f = g . h instead of f x = g (h x) thereby avoiding the need to give a name the argument to f. Cheers Ben BTW, A: No. Q: Should I include quotations after my reply? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What is the maturity of Haskell Web Frameworks
On 6/2/08 10:21 AM, Don Stewart wrote: aditya_siram: I am building a web-app that, in broad strokes, allows a leader to assign tasks to team members and allows team members to accept/reject/pick tasks that they want to do. I really like Haskell and I would like to use it to implement the solution. Are frameworks like Happs ready? Not so much in terms of documentation, but in functionality and stability. HAppS is nice (see hpaste.org for example, which is nice and simple, and has been running for over a year). Another nice option in Haskell is using something like HStringTemplate or the xhtml combinators with fastcgi hooked into GHC's concurrency mechanisms. If you're interested in the background of rolling your own web stuff, I like Paul Brown's description of building perpubplat here: http://mult.ifario.us/t/blog HTH, Keith ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: modelling C in Haskell ..
Galchin, Vasili wrote:
typedef struct blah
{
int val1;
union {
int val2;
struct {
int val3;
int val4;
}
}
}C_type;
question: in Haskell, can I embed definition of the union inside of the
C typedef, i.e. recursion definition? Or must I have a separate definition
for the union which I instantiate inside the Haskell typedef, i.e.
Haskell data?
No. Each definition of a data type must occur at the top-level. Also,
Haskell has only a very weak record system, a deficit that is generally
agreed to be one of Haskell's greatest weaknesses.
Like jcc, I'd also be interested what concrete problem prompted your
question. While I have often found it annoying that in Haskell e.g. record
labels are global in scope, I have never encountered a situation where I
wanted to have lexically nested data type declarations.
Cheers
Ben
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Re: [Haskell-cafe] hs-plugins compile error
Hi Don,
Is this the kind of thing you mean (I'm not really a darcs user; this is
the patch created by darcs record):
[Hide some names to remove ambiguity errors
Edsko de Vries [EMAIL PROTECTED]**20080602202001] {
hunk ./src/System/Plugins/Env.hs 76
-import Distribution.Package
+import Distribution.Package hiding (packageName)
hunk ./src/System/Plugins/PackageAPI.hs 43
-import Distribution.Package
+import Distribution.Package hiding (depends, packageName)
hunk ./src/System/Plugins/ParsePkgConfCabal.hs 9
-import Distribution.Package
+import Distribution.Package hiding (depends)
}
Edsko
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Re: [Haskell-cafe] Re: [ANN] bloomfilter 1.0 - Fast immutable and mutable Bloom filters
On Sat, May 31, 2008 at 6:22 PM, Jim Snow [EMAIL PROTECTED] wrote: In practice, one might use something like 32 hash tables. This yields a false positive rate of 1/(2^32). Their most obvious application is to store the dictionary for a spell checker in a space-efficient way, though I have a friend who wrote a paper on using them for router caches. One minor technicality is that you don't actually use k separate hash tables. You use k separate hash functions, and hash using different functions into the same physical table with a goal of having approximately half of the bits in the table set when all of your data is hashed. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Vancouver Haskell users meeting
Anyone else here from Vancouver (Canada)? I thought it would be great to have a little informal get-together at a local cafe and share how we're currently using Haskell, or really anything (problems, comparisons, useful software tools, etc.) in relation to Haskell. I'm scheduling a meeting for this Thursday, June 5th. for 7PM at Waazubee Cafe. (At Commercial Dr. and 1st Ave.) They have wireless internet access. I'll get a table near the back, bring my laptop, and will have a copy of Hudak's SOE book (the front cover is impossible to miss) out on the table. If anyone wants to meet, but this Thursday is not a good day for you, let me know what days are better and we'll move the meeting. If anyone is sure that they will come this Thursday, you might let me know, so I can have an idea about the resistance in changing the day, if needed. Thanks, Jon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Implementing ParseChart with Data.Map
Hi, I have to write ParseChart implementation with Data.Map/Set. The chart is type like this: type Chart k v = Map k (Set v) now I need operation like: insert :: k - v - Chart k v - Maybe (Chart k v) where the result is (Just _) if the (k,v) is actually added to the chart or Nothing if it was already there and nothing have to be done. The straight forward implementation is: case Map.lookup k chart of Nothing - Just (Map.insert k (Set.singleton v) chart) Just set | Set.member v set - Nothing | otherwise- Just (Map.insert k (Set.insert v set) chart) The problem with this is that both the Map and the Set are traversed twice. The first time from lookup/member and the second time from insert. Does someone have an idea how to do this with the current libraries? There are the Map.updateLookupWithKey and the Map.alter functions: updateLookupWithKey :: Ord k = (k - a - Maybe a) - k - Map k a - (Maybe a,Map k a) alter :: Ord k = (Maybe a - Maybe a) - k - Map k a - Map k a which are the closest that I need. The problem is that the first doesn't allow the client function to be called if there isn't matching key in the map and the second is doesn't allow to return value from the client function. What I really need is an alterLookúp function: alterLookúp :: Ord k = (Maybe a - (b,Maybe a)) - k - Map k a - (b,Map k a) The chart manipulation is in the tight loop of my application so I need fast code. Any other ideas? Regards, Krasimir ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Vancouver Haskell users meeting
Anyone else here from Vancouver (Canada)? I thought it would be great to have a little informal get-together at a local cafe and share how we're currently using Haskell, or really anything (problems, comparisons, useful software tools, etc.) in relation to Haskell. I'm scheduling a meeting for this Thursday, June 5th. for 7PM at http://www.waazubee.com/content/directions.php Waazubee Cafe - http://www.waazubee.com/content/directions.php (at Commercial Dr. and 1st Ave.) They have wireless internet access. I'll get a table near the back, bring my laptop, and will have a copy of Hudak's SOE book (the front cover is impossible to miss) out on the table. If anyone wants to meet, but this Thursday is not a good day for you, let me know what days are better and we'll move the meeting. If anyone is sure that they will come this Thursday, you might let me know, so I can have an idea about the resistance in changing the day, if needed. Thanks, Jon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Vancouver Haskell users meeting
jstrait: Anyone else here from Vancouver (Canada)? I thought it would be great to have a little informal get-together at a local cafe and share how we're currently using Haskell, or really anything (problems, comparisons, useful software tools, etc.) in relation to Haskell. I'm scheduling a meeting for this Thursday, June 5th. for 7PM at http://www.waazubee.com/content/directions.php Waazubee Cafe - http://www.waazubee.com/content/directions.php (at Commercial Dr. and 1st Ave.) They have wireless internet access. I'll get a table near the back, bring my laptop, and will have a copy of Hudak's SOE book (the front cover is impossible to miss) out on the table. If anyone wants to meet, but this Thursday is not a good day for you, let me know what days are better and we'll move the meeting. If anyone is sure that they will come this Thursday, you might let me know, so I can have an idea about the resistance in changing the day, if needed. Great! I've added these details to the events listing on http://haskell.org ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Implementing ParseChart with Data.Map
Hi Krasimir, insert :: k - v - Chart k v - Maybe (Chart k v) where the result is (Just _) if the (k,v) is actually added to the chart or Nothing if it was already there and nothing have to be done. insertLookupWithKey :: Ord k = (k - a - a - a) - k - a - Map k a - (Maybe a, Map k a) This should provide the information you need, without the double traversal of the data structure. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] hs-plugins compile error
after darcs record,
darcs send -o file.patch
and then send file.patch via email to the maintainer.
2008/6/2 Edsko de Vries [EMAIL PROTECTED]:
Hi Don,
Is this the kind of thing you mean (I'm not really a darcs user; this is
the patch created by darcs record):
[Hide some names to remove ambiguity errors
Edsko de Vries [EMAIL PROTECTED]**20080602202001] {
hunk ./src/System/Plugins/Env.hs 76
-import Distribution.Package
+import Distribution.Package hiding (packageName)
hunk ./src/System/Plugins/PackageAPI.hs 43
-import Distribution.Package
+import Distribution.Package hiding (depends, packageName)
hunk ./src/System/Plugins/ParsePkgConfCabal.hs 9
-import Distribution.Package
+import Distribution.Package hiding (depends)
}
Edsko
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Re: [Haskell-cafe] Implementing ParseChart with Data.Map
On Mon, 2008-06-02 at 22:35 +0200, Krasimir Angelov wrote: The problem with this is that both the Map and the Set are traversed twice. The first time from lookup/member and the second time from insert. Does someone have an idea how to do this with the current libraries? The chart manipulation is in the tight loop of my application so I need fast code. Any other ideas? I'm not sure if it helps your application but we had a discussion on #haskell the other day about Data.Map and were talking about a general insert/modify/delete operator like: modify :: k - Map k e - (e, Maybe e - Map k e) so it's a lookup that returns the element at k and also a continuation that lets you rebuild a new map with an altered element. I guess that doesn't account for the element not existing. There's probably a generalisation that does. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] cabal install fail for happs-hsp-template
On Mon, 2008-06-02 at 09:42 -0700, Thomas Hartman wrote: Can cabal install be made to work for this package? * [EMAIL PROTECTED]:~sudo cabal install happs-hsp-template [sudo] password for thartman: cabal: internal error: could not construct a valid install plan. The proposed (invalid) plan contained the following problems: Package Cabal is required by several packages, but they require inconsistent versions: package ghc-6.8.2 requires Cabal-1.2.3.0 package plugins-1.2 requires Cabal-1.5.2 The package deps are not actually inconsistent, the problem is that the current cabal-install dependency resolution algorithm is completely naive and comes up with an invalid install plan. I'll let people know when the new dep resolver for cabal-install is ready (hopefully just a few days now). It should address this issue. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Implementing ParseChart with Data.Map
Not completely! This is a possible implementation: case insertLookupWithKey (\_ - Set.union) k (Set.singleton v) chart of (Nothing, chart) - Just chart (Just set, chart) | Set.member v set - Nothing | otherwise - Just chart but notice that the set is still traversed twice. On Tue, Jun 3, 2008 at 12:07 AM, Neil Mitchell [EMAIL PROTECTED] wrote: Hi Krasimir, insert :: k - v - Chart k v - Maybe (Chart k v) where the result is (Just _) if the (k,v) is actually added to the chart or Nothing if it was already there and nothing have to be done. insertLookupWithKey :: Ord k = (k - a - a - a) - k - a - Map k a - (Maybe a, Map k a) This should provide the information you need, without the double traversal of the data structure. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Implementing ParseChart with Data.Map
Hi case insertLookupWithKey (\_ - Set.union) k (Set.singleton v) chart of (Nothing, chart) - Just chart (Just set, chart) | Set.member v set - Nothing | otherwise - Just chart but notice that the set is still traversed twice. Yes, I missed that bit. I don't see any way of reducing that, other than using an unsafePerformIO and IORef to track the combining function - which is probably a really bad idea. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Newbie question] -- Looping stdin until condition is met
On 5/30/08, Martin Blais [EMAIL PROTECTED] wrote: Dear Philip, could you point your virtual finger towards a reference/paper/book/any-bleeping-thing that would help this simple beginner understand why it doesn't work in this case? I'm trying to picture why a read function that terminates the program would be useful anywhere. In fact, any library function other than something like UNIX's exit or kill which terminates my program is not really welcome in any of my computer programs, but then again, I haven't yet been illuminated by the genie of pure functional languages. A reference would be awesome. As others have pointed out, the reason why it doesn't work is due to lazy evaluation; the exception is hidden in a pure value and isn't triggered until some other bit of code causes the pure value to be evaluated. You can force the exception to be generated in your catch block by using seq (or $!, which is implemented using seq). This forces the evaluation to happen at that point, although there are a lot of gotchas involved; for Int it works fine, though. Your question, then, requires asking why would you want to hide an exception in a pure value? The answer to that is quite interesting, but here's a simpler example that might enlighten you: head :: [a] - a head (x:_) = x head _ = error head: empty list Just as you are required to prove before calling head that you aren't passing an empty list, for your program to be total, you should prove before calling read that the string parses properly. If you can't provide that proof (because, in this case, the string is provided by the user), you should be using another function for parsing. Don suggested reads to implement maybeRead, which seems like a great idea to me. -- ryan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Newbie question] -- Looping stdin until condition is met
Hi The best thing to do is bypass read and use 'reads' to define your own safe read. maybeRead :: Read a = String - Maybe a maybeRead s = case reads s of [(x, )] - Just x _ - Nothing Or just use the Safe package: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/safe http://hackage.haskell.org/packages/archive/safe/0.2/doc/html/Safe.html#v%3AreadMay Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ghc 6.8.2 issue
Hi Duncan, Not sure I agree the behavior is ok. E.g. here is a build of mmap: [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs clean cleaning... [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs configure Configuring bytestring-mmap-0.2.0... [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs build Preprocessing library bytestring-mmap-0.2.0... Building bytestring-mmap-0.2.0... [1 of 3] Compiling System.IO.Posix.MMap.Internal ( System/IO/Posix/MMap/Internal.hs, dist/build/System/IO/Posix/MMap/Internal.o ) [2 of 3] Compiling System.IO.Posix.MMap.Lazy ( System/IO/Posix/MMap/Lazy.hs, dist/build/System/IO/Posix/MMap/Lazy.o ) [3 of 3] Compiling System.IO.Posix.MMap ( System/IO/Posix/MMap.hs, dist/build/System/IO/Posix/MMap.o ) /usr/bin/ar: creating dist/build/libHSbytestring-mmap-0.2.0.a at this point rebuild and install the unix package ... [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs clean cleaning... [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs configure Configuring bytestring-mmap-0.2.0... [EMAIL PROTECTED]:~/FTP/Haskell/bytestring-mmap-0.2.0$ runhaskell Setup.lhs build Setup.lhs: error reading dist/setup-config; run setup configure command? dist/setup-config is not being populated at the end. In your response below, are you saying that teh segfaults occur because ghc itself relies on the unix package? Thanks, Vasili On Mon, Jun 2, 2008 at 5:38 AM, Duncan Coutts [EMAIL PROTECTED] wrote: On Mon, 2008-06-02 at 00:07 -0500, Galchin, Vasili wrote: Hello, I have been developing new code for the unix package. I have run into what I think are ghc 6.8.2 anomalies but couldn't see a pattern. Possibly now I do. I have been using the 32-bit x86 ghc binary that I downloaded from http://www.haskell.org and running on Ubuntu Linux. I am pretty I can repeat now. Everything is ok until I do sudo runhaskell Setup.hs install which installs a new unix package that I just built. Of course the intall installs into /usr/local/lib/unix-2.3.0.0/ghc-6.8.2. The install seems to destroy some ghc compiler state under /usr/local ... That sounds right. You're replacing the unix-2.3.0.0 library that comes with ghc-6.8.2 with your own version. It is highly unlikely to be ABI compatible with the one you are replacing and so all the other packages that already depends on the existing unix-2.3.0.0 library end up broken. You'd expect this kind of breakage to be exposed as link errors and segfaults. I suggest you do not replace any of the libraries that come with ghc. To be more precise, it is perfectly ok to *add new versions* but it is not ok to *replace existing versions* without rebuilding all the other libs that depend on it. Make sense? So if you really want to make changes to the unix lib, make sure you change the version number too. I also suggest not installing the packages as root, just install them locally. That way you can guarantee you never mess up your ghc install. You would be able to revert to a clean ghc install just by removing your ~/.ghc/$arch/ghc-6.8.2/package.conf file which will unregister *all* locally registered packages. To unregister individual packages use ghc-pkg --user unregister $pkgname Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Mutually Recursive Modules
G'day all. Quoting Isaac Dupree [EMAIL PROTECTED]: Luckily, it is very often the case that your code will be better off anyway if refactored to have less module recursion. (though not always.) Nonetheless, I prefer not to leave the robustness of my code to luck. Besides, if I liked structuring code around artificial language restrictions, I'd be programming in C, not Haskell. Cheers, Andrew Bromage ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ghc 6.8.2 issue
Duncan, By installing localling, I runhaskell Setup.hs configure --prefix=$HOME plus add local path to LD_LIBRARY_PATH and LD_RUN_PATH? On Linux, does ghc use .so's or is it linked statically? Vasili On Mon, Jun 2, 2008 at 5:38 AM, Duncan Coutts [EMAIL PROTECTED] wrote: On Mon, 2008-06-02 at 00:07 -0500, Galchin, Vasili wrote: Hello, I have been developing new code for the unix package. I have run into what I think are ghc 6.8.2 anomalies but couldn't see a pattern. Possibly now I do. I have been using the 32-bit x86 ghc binary that I downloaded from http://www.haskell.org and running on Ubuntu Linux. I am pretty I can repeat now. Everything is ok until I do sudo runhaskell Setup.hs install which installs a new unix package that I just built. Of course the intall installs into /usr/local/lib/unix-2.3.0.0/ghc-6.8.2. The install seems to destroy some ghc compiler state under /usr/local ... That sounds right. You're replacing the unix-2.3.0.0 library that comes with ghc-6.8.2 with your own version. It is highly unlikely to be ABI compatible with the one you are replacing and so all the other packages that already depends on the existing unix-2.3.0.0 library end up broken. You'd expect this kind of breakage to be exposed as link errors and segfaults. I suggest you do not replace any of the libraries that come with ghc. To be more precise, it is perfectly ok to *add new versions* but it is not ok to *replace existing versions* without rebuilding all the other libs that depend on it. Make sense? So if you really want to make changes to the unix lib, make sure you change the version number too. I also suggest not installing the packages as root, just install them locally. That way you can guarantee you never mess up your ghc install. You would be able to revert to a clean ghc install just by removing your ~/.ghc/$arch/ghc-6.8.2/package.conf file which will unregister *all* locally registered packages. To unregister individual packages use ghc-pkg --user unregister $pkgname Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
