Re: [Haskell-cafe] hoogle down

? 2009/11/28 Neil Mitchell ndmitch...@gmail.com Hi Keith, Thanks for pointing this out. I've no idea why it's failing, but will check once I get home - unfortunately the machine I'm currently on doesn't permit me to ssh in and find out. Thanks, Neil On Sat, Nov 28, 2009 at 6:53 AM, Keith

Re: [Haskell-cafe] Some useful TH templates

Hi Yair, I wrote some Template Haskell templates that I think may be of use to others. The first generates in and with functions for newtypes. This looks very nice. Have you thought about putting this code in to the Derive package? (http://community.haskell.org/~ndm/derive, and also on

[Haskell-cafe] community.haskell.org is down

Hi, community.haskell.org isn't responding, I get connection failures. Thanks, Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] haskell-src-exts Question

Hi Adding brackets that MUST have been there, by default, sounds like a great idea. The alternative is getting it wrong, so I think that's very safe. Adding brackets that MIGHT have been there is a lot less clear cut. One important consideration is that the fixities you parse/pretty-print with

Re: [Haskell-cafe] haskell-src-exts Question

Hi Daniel, Funny, I did the opposite approach the other day (not saying either is better :)); that is: parenthesize everything while building the AST (with a wrapper for App) and then: I have utilities in HLint for that too - but I don't want to remove users brackets automatically :-) Btw,

Re: [Haskell-cafe] Opinion about JHC

Hi John, Do you use jhc when you develop jhc?  I.e., does it compile itself. For me, this is the litmus test of when a compiler has become usable. I mean, if even the developers of a compiler don't use it themselves, why should anyone else? :) Well, this touches on another issue, and that

Re: [Haskell-cafe] haskell-src-exts Question

Hi Niklas, Do I have to write my own prettyprinter? Do I have to put in explicit parentheses? The latter seems unsatisfactory as my generated AST is unambiguous and bracketing ought to be part of the prettyprinter. The former would be quite a lot of code as there are many cases to

Re: [Haskell-cafe] faster compiling for ghc

Hi, I'd really love a faster GHC! I spend hours every day waiting for GHC, so any improvements would be most welcome. I remember when developing Yhc on a really low powered computer, it had around 200 modules and loaded from scratch (with all the Prelude etc) in about 3 seconds on Hugs. ghc

Re: [Haskell-cafe] The weirdest error I've ever seen...

Hi Joe, Serious question now, There's a fair amount of definitely irrelevant code (like the definition of the `Email` type, etc), should I post that in the report too (assuming it doesn't work in 6.12 or I can't get 6.12 working to try it)? http://hackage.haskell.org/trac/ghc/wiki/ReportABug

Re: [Haskell-cafe] Hoogle is great but ...

Following up on this rather old thread, if you want to see a module which has lots of input/output example pairs, and properties, in the documentation then look at filepath (hoogle for takeExtension as an example). These properties are also automatically transformed in to test cases, so filepath

Re: [Haskell-cafe] hSeek in Windows

Hi Philippos, The secret is there in the error message: seek operations on text-moddles are not allowed on this platform You need to set your file in to binary mode, with hSetBinaryMode (http://haskell.org/hoogle/?hoogle=hSetBinaryMode) or openBinaryFile

Re: [Haskell-cafe] hackage is down.

For future reference, if Hackage or community is down where should that be reported to? On Sun, Nov 1, 2009 at 7:01 PM, Don Stewart d...@galois.com wrote: This has been reported to the sysadmins. tphyahoo: http://hackage.haskell.org ___

[Haskell-cafe] Re: Suggested additions to System.FilePath.Posix/Windows

Hi Marcus, Thanks for your suggestions. I'm a Windows user so aren't really qualified to comment on these suggestions - it depends what Posix users would like. I suggest you follow the Library Submission Process - filepath is now a core library, and as such I don't have the freedom/power to

[Haskell-cafe] Community.haskell.org is down

Hi, http://community.haskell.org/ seems to be down for me. In general, who should this be reported to? Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Error during hlint install ?

Hi Dusan,  Am I doing something wrong if I get the following error during cabal installation of hlint? Is there any way how to solve it? The problem is that version 1.15 of hscolour released recently is incompatible with 1.13 which HLint was being tested against. I've now switched over to

Re: [Haskell-cafe] Unifcation and matching in Abelian groups

Hi, I ran your code thought HLint (http://community.haskell.org/~ndm/hlint), and it suggested a couple of things (mainly eta reduce). The most interesting suggestions are on your main function: main :: IO () main = do done - isEOF case done of True - return ()

Re: [Haskell-cafe] Unifcation and matching in Abelian groups

Hi I've given up on using if-then-else in do expressions.  They confuse emacs.  There is a proposal for Haskell' to fix the problem, but until then, I will not use them in do expressions. It's a shame, there are ways of indenting them that work, but they're not as natural. It's a wart, but it

Re: [Haskell-cafe] Request for comments - hdnsomatic

de Guadalajara 2009/8/16 Neil Mitchell ndmitch...@gmail.com Hi An easy way to get some instant feedback is to run HLint on it: http://community.haskell.org/~ndm/hlint The results are: C:\Neil\hlinthlint Example.hs Example.hs:42:1: Warning: Use liftM Found:  readFile p = return

Re: [Haskell-cafe] Re: Changelogs and available since

Hi I would use hoogle for this. Currently it stores the package name and the symbols of the modules about a package. What do you think about hayoo?  I prefer this to hoogle, as hayoo has more complete database across hackage packages, AFAIK Hayoo gets it package database out of haddock with

Re: [Haskell-cafe] Request for comments - hdnsomatic

Hi An easy way to get some instant feedback is to run HLint on it: http://community.haskell.org/~ndm/hlint The results are: C:\Neil\hlinthlint Example.hs Example.hs:42:1: Warning: Use liftM Found: readFile p = return . lines = return . map (second tail . break (== '=') . filter (/= ' '))

Re: [Haskell-cafe] Using -Nx Option with GHC

Hi Mark, I compile with ghc --make -O2 -threaded That should work - try deleting all .o/.obj files and the executable and trying to compile again. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org

Re: [Haskell-cafe] Request for Changelogs

Hi I’m involved in packaging Haskell stuff for Debian. Now, the Debian tools we have for that tell me „Hlint has a new version, 1.6.5, which is newer than the one you packages, 1.6.4. Huh, nice. What has changed? Is it relevant for Debian? Is it worth a new upload? There is no easy way to

Re: [Haskell-cafe] Request for Changelogs

Hi http://community.haskell.org/~ndm/darcs/hlint/CHANGES.txt That will now be updated for future HLint releases. Thanks, Neil On Thu, Aug 6, 2009 at 3:49 PM, Joachim Breitnerm...@joachim-breitner.de wrote: Hi, Am Donnerstag, den 06.08.2009, 15:39 +0100 schrieb Neil Mitchell: So please

Re: [Haskell-cafe] Hugs faster and more reliable than GHC for large list monad 'do' block

Hi I think the issue you're running in to with 6.4 is this one: http://hackage.haskell.org/trac/ghc/ticket/830 - known and fixed a while back. Thanks Neil On Thu, Aug 6, 2009 at 9:59 PM, Dan Westonweston...@imageworks.com wrote: I assume for the return line, you meant to return a list, not a

Re: [Haskell-cafe] Typeclass for functions taking different kinds of strings

Hi is there currently a library that makes unifying them easy? I currently use this library: http://community.haskell.org/~ndm/darcs/tagsoup/Text/StringLike.hs Not yet released, and rather specific to what I was wanting to do, but does work for me. I'm happy for people to steal bits from that

Re: [Haskell-cafe] Typeclass for functions taking different kinds of strings

Hi It looks nice but is not really a solution for passing large amounts of data efficiently. Converting everything to String creates too much overhead for large chunks of data. There is uncons, which never creates big strings. But yes, adding more bulk operations (i.e. lookup) might be

Re: [Haskell-cafe] Haskell interface files: Why used? What about same data in object files?

Hi Some good reasons for having a separate interface are:  they can be human-readable and human-writable (ghc's do not fulfill this criterion); they can be used to bootstrap mutually recursive modules in the absence of any object files (ghc uses .hs-boot files instead); other tools can

Re: [Haskell-cafe] Need feedback on my Haskell code

Hi Kashyap, My first suggestion would be to run HLint over the code (http://community.haskell.org/~ndm/hlint) - that will spot a few easy simplifications. Thanks Neil On Tue, Jul 28, 2009 at 2:04 PM, CK Kashyapck_kash...@yahoo.com wrote: Hi Everyone, I managed to write up the line drawing

Re: [Haskell-cafe] Implicit concatenation in list comprehensions

Except that it's ugly compared to the proposed extension. With the extension you can put things in the same, right place: renderGhcOptions opts =     ghcOptExtraPre opts  -- source search path  ++ [ -i      | not (null (ghcOptSearchPath opts)) ]  ++ [ -i, dir | dir - ghcOptSearchPath opts

Re: [Haskell-cafe] Implicit concatenation in list comprehensions

Hi Max, For fun, I spent a few hours yesterday implement support for this syntax in GHC, originally propsed by Koen Claessen: [k, =, v, | (k, v) - [(foo, 1), (bar, 2)] [foo, =, 1, , bar, =, 2, ] This is a generalisation of list comprehensions that allows several items to be

Re: [Haskell-cafe] Parsing .dot files?

Hi I have some code, but never got round to uploading it or turning it in to a package. If the graphviz package doesn't have what you want I'm happy to give you a copy. (I would attach the code but I don't have it on this machine) Thanks Neil On Wed, Jun 24, 2009 at 7:38 AM, minh

Re: [Haskell-cafe] HXT XmlPicklers - TH Derivation

Hi Max, I have developed some simple TH code to automatically derive XmlPickler instances for my types and if there is interest, I will clean it up and submit a patch.  Its not complete, but is a start.  Any interest? Why not submit it to derive: http://community.haskell.org/~ndm/derive

Re: [Haskell-cafe] GSoC update: sneak peek at the live heap profiler

Hi Gergely, I haven't seen this blog on planet.haskell.org, but it definitely should be! Instructions on how to have it added are on that page. Thanks, Neil 2009/6/3 Patai Gergely patai_gerg...@fastmail.fm: Hello everyone, finally there's a bit of eye candy for anyone interested in the heap

Re: [Haskell-cafe] Anglohaskell?

Sounds fun! I have no time to organise it, but someone should. It really isn't that hard! Thanks Neil On Mon, May 25, 2009 at 4:47 PM, Philippa Cowderoy fli...@flippac.org wrote: Is anyone up for Anglohaskell this year? Perhaps more importantly, is anyone willing to step forward to run it? I

[Haskell-cafe] Re: ANN: New repository and trac for haskell-src-exts

Hi Niklas, Do you want people to cc bugs they want to vote for - like the GHC people do? Thanks Neil On Tue, May 26, 2009 at 12:56 AM, Niklas Broberg niklas.brob...@gmail.com wrote: Hi all, In preparation for my GSoC project, I've set up some new infrastructure for the haskell-src-exts

[Haskell-cafe] community.haskell.org and code.haskell.org problems

Hi, I regularly (almost daily) have problems reaching both community and code.haskell.org, getting 500 server error messages. I've decided to make all my Haskell code available on community, which means that when it goes down, I can't access my repos - which is not great. Is there a reason for

[Haskell-cafe] community.haskell.org and code.haskell.org problems

Hi, I regularly (almost daily) have problems reaching both community and code.haskell.org, getting 500 server error messages. I've decided to make all my Haskell code available on community, which means that when it goes down, I can't access my repos - which is not great. Is there a reason for

Re: [Haskell-cafe] haskellnet

Hi Email the original author, if you can. Ideally work with them to upload a working version to hackage. If they're not interested hopefully they'll make you the new maintainer. If you can't contact them, just upload a new version anyway - as long as it's done for the benefit of the community and

Re: [Haskell-cafe] Hoogle: converting binary .hoo into text?

Hi Sure. We're building with a graphical representation of a Haskellish language (a tiny subset of Haskell actually). The target audience is graphical artists and designers. For testing, I would like to populate the library with primitives taken from the Haskell base libraries.  I tried

Re: [Haskell-cafe] Generating Haskell with associated types (and kind annotations)

Hi I guess I should write the skeleton of the code I want to generate, get HSE to parse it, and then replace the parts I want to change of the AST with what I need? Is there a nicer way (TH-like?) to get the modified AST into GHC than prettyprinting the AST again and asking GHC to compile

Re: Can HLint help spot space leaks? (was: Re: [Haskell-cafe] Generating Haskell with associated types (and kind annotations))

Hi Jason, Hi Neil, A bit off-topic, but your post reminded me:  Does HLint currently help the user find space leaks?  For example, does it recommend strict folds instead of lazy folds?  I looked at the FAQ but this was not listed.  I don't really know how feasible this is. It spots when you

Re: [Haskell-cafe] Generating Haskell with associated types (and kind annotations)

Hi Dan, I was wondering whether anyone had any suggestions on a good way to generate repetitive code with associated types and kind annotations. haskell-src-exts is the answer: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haskell-src-exts From the project description:

Re: [Haskell-cafe] Why is Bool no instance of Num and Bits?

that. Is that a GHC thing? Is it strictly necessary? Seems like it could be done in the Num instance for Integers, Ints, etc. On Fri, May 8, 2009 at 11:51 AM, Neil Mitchell ndmitch...@gmail.com wrote: Err, I'm not seeing the danger of this (+) :: forall a. (Num a) = a - a - a Doesn't

Re: [Haskell-cafe] Why is Bool no instance of Num and Bits?

Err, I'm not seeing the danger of this (+) :: forall a. (Num a) = a - a - a Doesn't this require the two parameters to be the same instance of Num? I didn't at first, then I remembered: 1 + True = fromInteger 1 + True And if we have Num for Bool, it type checks. Thanks Neil

Re: [Haskell-cafe] Why is Bool no instance of Num and Bits?

Does that also mean that you could write: if 3 - 4 then ... else ...  (= if (fromInteger 3 :: Bool) - (fromInteger 4 :: Bool) then ... else ...) No. 3 - 4 is an Integer, the proposal is to convert Bools to Ints, not Ints to Bools. Of course, Lennart has been asking for precisely this

Re: [Haskell-cafe] Research in functional programming

Hi http://www.haskell.org/haskell-symposium/2009/ And you've got til Friday! Thanks, Neil On Sun, May 3, 2009 at 10:13 PM, Louis Wasserman wasserman.lo...@gmail.com wrote: Where might I find or submit a paper on functional data structures? Examples I've found so far include ICFP and the JFP,

Re: [Haskell-cafe] chr/ord?

Hi But I get this when I try to use it: sheep.hs:30:22: Not in scope: `mplus' [mich...@localhost ~]$ You need to import Control.Monad. You can find answers to these sorts of questions with Hoogle: http://haskell.org/hoogle/?hoogle=mplus Thanks Neil

Re: [Haskell-cafe] can I query if package is in Hackage?

Hi   Hoogle allows me to query about Haskell functionality. But is there a mechanism for querying about a package, e.g. Swish? Yes: http://haskell.org/hoogle/?hoogle=hoogle+%2Bhackage http://haskell.org/hoogle/?hoogle=swish+%2Bhackage Answer, swish is not on hackage, but hoogle is.

Re: Is 78 characters still a good option? Was: [Haskell-cafe] breaking too long lines

Hi I believe it is a good practice too keep each line short and easy to read.  The following is taken from python style guide.  Maximum Line Length    Limit all lines to a maximum of 79 characters.    There are still many devices around that are limited to 80 character    lines; plus,

Re: [Haskell-cafe] Getting the x out

Hi It's not too hard. You wanted a function that converted Maybe a - a, you just Hoogle for it: http://haskell.org/hoogle/?hoogle=Maybe+a+-+a Thanks Neil On Wed, Apr 22, 2009 at 2:07 AM, michael rice nowg...@yahoo.com wrote: Got it! I figured there must be some way to unpack it. My

[Haskell-cafe] Parallel combinator, performance advice

Hi, I've written a parallel_ function, code attached. I'm looking for criticism, suggestions etc on how to improve the performance and fairness of this parallel construct. (If it turns out this construct is already in a library somewhere, I'd be interested in that too!) The problem I'm trying to

Re: [Haskell-cafe] System.Process.Posix

Hi Is it me or the above package is not included in Hoogle? afair, Neil, being windows user, includes only packages available for his own system there was a large thread a few months ago and many peoples voted for excluding any OS-specific packages at all since this decreases portability

[Haskell-cafe] Re: Parallel combinator, performance advice

Hi The problem I'm trying to solve is running system commands in parallel. system commands means execution of external commands or just system calls inside Haskell? Calls to System.Cmd.system, i.e. running external console processes. It's a make system I'm writing, so virtually all the

[Haskell-cafe] Re: Re[2]: Parallel combinator, performance advice

Hi Sebastian: How about using unsafeInterleaveIO to get a lazy suspension of the result of each action, and then using par to spark off each of them? If that works you can reuse the existing task-parallel system of GHC to do the heavily lifting for you, instead of having to write your

[Haskell-cafe] Re: Re[2]: Parallel combinator, performance advice

Hi Bulat, btw, if all that you need is to limit amount of simultaneous System.Cmd.system calls, you may go from opposite side: wrap this call into semaphore: sem = unsafePerformIO$ newQSem numCapabilities mysystem = bracket_ (waitQSem sem) (signalQSem sem) . system and implement para as

[Haskell-cafe] Re: Re[5]: Parallel combinator, performance advice

Hi par is likely to spark all the computations, and then switch between them - which will mean I've got more than N things running in parallel. | par/GHC RTS limits amount of Haskell threads running simultaneously. | with a system call marked as safe, Capability will be freed while we |

Re: [Haskell-cafe] EclipseFP proposal for Google Summer of Code

Hi Thomas, I send this e-mail because of possible scheduling issues: I will be away starting on April 15. So, if you want to ask me things, have suggestions for improvement, or want to do an interview or something, this can only be done *before* that date. I am pretty sure all the questions

Re: [Haskell-cafe] about import alias

Hi You can always do {-# INLINE short #-} short = C.veryLongFunctionNameThatIReallyDoNotWantToTypeOutEveryTimeIUseIt The INLINE pragma is not necessary, if an optimising compiler fails to inline that then it's not very good. However, you might want to consider the (evil) monomorphism

Re: [Haskell-cafe] Announcement: Beta of Leksah IDE available

Hi Just tried it out, a few notes: * Very easy install - if only gtk2hs could be installed with cabal it would have been perfect. * Select the package you have installed. I didn't have a clue what to do here. Do you mean where I keep my Haskell programs? Or where GHC installs them? Can't you

Re: [Haskell-cafe] GSoC proposal

Hi Csaba, Do you mean you have submitted your proposal to the Haskell wiki thing, or to the official google application? If its the wiki, then submit it to the official Google thing as well. You can always edit it later, but the deadline is fast approaching. If its the Google thing, then not

Re: [Haskell-cafe] Copying data files when installing, using Cabal

Hi Henk-Jan, It works for me, see for example HLint: http://community.haskell.org/~ndm/darcs/hlint And a blog I wrote on it: http://neilmitchell.blogspot.com/2008/02/adding-data-files-using-cabal.html The data files are copied in to the data directory upon install. The data-files: bit must be

Re: [Haskell-cafe] Language.Haskell.Parser question

Hi f1 = foo 5 f2 = foo 8 f3 = foo 9  I want to extract a list [5, 8, 9] (suppouse function takes only one argument) Firstly, use haskell-src-exts and Language.Haskell.Exts - its a much better library, deals with many extensions, and gives you everything Language.Haskell did. parser

Re: [Haskell-cafe] Language.Haskell.Parser question

Hi John, Actually, looking at the docs for UniplateStr[1], isn't there an error in the following example statement in the Queries section? vals x = [Val i | i - universe x] Shouldn't that be: vals x = [i | Val i - universe x] Yep, you are indeed right. I've fixed the examples in the darcs

Re: [Haskell-cafe] Language.Haskell.Parser question

it would be sensible to name such a function vals... Thanks Neil On Thu, Mar 26, 2009 at 4:23 PM, Neil Mitchell ndmitch...@gmail.com wrote: Hi John, Actually, looking at the docs for UniplateStr[1], isn't there an error in the following example statement in the Queries section

Re: [Haskell-cafe] Whats the use of !

Hi A quick Hoogle for ! : http://haskell.org/hoogle/?hoogle=! Gives the first answer as: http://www.haskell.org/haskellwiki/Keywords#.21 If that isn't clear, someone should expand on it or give further links to useful resources. Thanks Neil 2009/3/25 Harsh Verma hjve...@hotmail.com: I have

Re: [Haskell-cafe] Google Summer of Code: Is this idea useful for the community?

The main thing about reddit is the community, not the underlying code, and while I'm sure a SoC project could do something with the code, I don't see how you could build such a community. And if you did build a big community, then I think it would spiral out of control with only a summers work to

Re: [Haskell-cafe] Re: Haskell Logo write-in candidate

semi-rant warning: This whole badge/logo business seems to me to be an excellent example of Parkinson's law of triviality (choosing the colour of the bikeshed). We have a large (too large) number of variations on relatively few themes and a really sophisticated voting system, but no very

Re: [Haskell-cafe] least fixed points above something

I've used a similar function myself, but why write it in such a complicated way? How about lfp :: Eq a = (a - a) - a - a lfp f x  | f x == x = x  | otherwise = lfp f (f x) I've used a similar function too, but your version computes f x twice per iteration, I wrote mine as: fix :: Eq a =

Re: [Haskell-cafe] least fixed points above something

:) On 19 Mar 2009, at 16:21, Neil Mitchell wrote: I've used a similar function myself, but why write it in such a complicated way? How about lfp :: Eq a = (a - a) - a - a lfp f x  | f x == x = x  | otherwise = lfp f (f x) I've used a similar function too, but your version computes f x twice per

Re: [Haskell-cafe] least fixed points above something

Can you give an example of when CSE would not be the way to go? if length (replicate 'a' 1) == 1 then [] else head (replicate 'a' 1) This program will use O(1) memory. If we perform CSE: if length x == 1 then [] else head x where x = replicate 'a' 1 Now we use 1 cells of

Re: [Haskell-cafe] can GHC build an executable from a C source file?

Yhc used to do this (when you could still build it). Turns out that on Windows using gcc that gets installed with ghc isn't particularly fun, while ghc makes a very pleasant build experience. Something to do with directory layouts, head file searching, and what is on the %PATH% by default. Thanks

Re: [Haskell-cafe] Map in Terms of Fold in terms of Map

Hi Mark, What's the definition of foldr in terms of map? As far as I was aware, its not possible. And as it happens, map is (or is sometimes) defined in term of foldr :-) While you can use mutual recursion, you can't define a in terms of b and b in terms of a unless one of them actually does

Re: [Haskell-cafe] View patterns and warnings about overlapping or non-exhaustive patterns

Hi Stephan, I'm working on a data structure that uses Data.Sequence a lot, so views are important and I tried to simplify my code using view patterns. The problem is, that I keep getting warnings about both overlapping and non-exhaustive pattern matches. A simple test case:

Re: [Haskell-cafe] Data.Binary stack overflow with Data.Sequence String

Hi Gwern, I get String/Data.Binary issues too. My suggestion would be to change your strings to ByteString's, serisalise, and then do the reverse conversion when reading. Interestingly, a String and a ByteString have identical Data.Binary reps, but in my experiments converting, including the cost

Re: [Haskell-cafe] Data.Binary stack overflow with Data.Sequence String

Avoid massive reductions in runtime while maintaining the same API? I did move to using ByteString's internally for those bits later on, but reading String's from Data.Binary with a ByteString+unpack went much more quickly than reading String's On Thu, Mar 5, 2009 at 7:35 PM, Don Stewart

Re: [Haskell-cafe] Test if a file is empty or stat in haskell

Hi I am on Linux. BTW, Hoogle does not seem to  know about System.Posix.Files, though it did point me to System.IO.FileSize which would also have served the purpose. To build the Hoogle libraries I need to build the packages. I run Windows not Linux, so its a bit difficult to index

Re: [Haskell-cafe] Difficulties in accessing inner elements of data types

Hi David, What you are wanting to do is query and transform a reasonably large AST. Fortunately there are solutions, generic programming should do exactly what you want without too much hassle. I'd personally recommend taking a look at the Uniplate library, starting by reading the Haskell

Re: [Haskell-cafe] Assignment of grayCode

Hi I'm working on a project for my university. But I do not understand the assignment. If you don't understand a university assignment the best place to ask is the person who set the assignment. If you don't understand what is being asked, most lecturers will provide clarification. It asks

Re: [Haskell-cafe] Data.Binary, strict reading

Hi With binary 0.5,    src - decodeFile _make/_make    return $! src I'm pretty sure I was on the latest Cabal released version of binary, and the above trick did not work. It _usually_ worked, but every so often I'd get a locking error. Shouldn't you use rnf[1]? Also, there seems to be

[Haskell-cafe] Data.Binary, strict reading

Hi, I want to read a file using Data.Binary, and I want to read the file strictly - i.e. when I leave the read file I want to guarantee the handle is closed. The reason is that (possibly immediately after) I need to write to the file. The following is the magic I need to use - is it all

[Haskell-cafe] Data.Binary poor read performance

Hi, In an application I'm writing with Data.Binary I'm seeing very fast write performance (instant), but much slower read performance. Can you advise where I might be going wrong? The data type I'm serialising is roughly: Map String [Either (String,[String]) [(String,Int)]] A lot of the

Re: [Haskell-cafe] Hoogle and Network.Socket

Hi I don't want to get in to a platform war (which I certainly don't have time to engage in - plus its not nearly as much fun over email vs sitting in a pub with some beer having a platform war). Martijn's thoughts of +windows, +unix, +os is exactly right, I'm happy to let users say oh, please

Re: [Haskell-cafe] Hoogle and Network.Socket

a small issue if you are searching on one platform and programming on/for another platform.  But the flags could still be used. Thomas On Thu, Feb 19, 2009 at 9:11 AM, Neil Mitchell ndmitch...@gmail.com wrote: Hi http://haskell.org/hoogle/?q=socket+%2Bnetwork By default it searches

Re: [Haskell-cafe] Hoogle and Network.Socket

Hi http://haskell.org/hoogle/?q=socket+%2Bnetwork By default it searches the libraries supplied with Windows apart from Network (for various technical reasons). If you add +network it will then search the network library. What libraries should Hoogle search by default? What flags should be

Re: [Haskell-cafe] Looping after compiling with cabal

Hi Henk-Jan, I believe cabal adds a -O on the command line, perhaps try ghc --make -O (after deleting all object files) Thanks Neil On Mon, Feb 16, 2009 at 12:04 PM, Henk-Jan van Tuyl hjgt...@chello.nl wrote: L.S., I have updated wxFruit to compile with GHC 6.10.1, but when I compil using

Re: [Haskell-cafe] createProcess shutting file handles

However the createProcess command structure has the close_fds flag, which seems like it should override that behaviour, and therefore this seems like a bug in createProcess. close_fds :: Bool Close all file descriptors except stdin, stdout and stderr in the new process

Re: [Haskell-cafe] createProcess shutting file handles

Hi What have I done wrong? Did createProcess close the handle, and is there a way round this? The docs for runProcess says: Any Handles passed to runProcess are placed immediately in the closed state. but the equivalent seems to be missing from the documentation for

Re: [Haskell-cafe] createProcess shutting file handles

Hi However the createProcess command structure has the close_fds flag, which seems like it should override that behaviour, and therefore this seems like a bug in createProcess. close_fds :: Bool Close all file descriptors except stdin, stdout and stderr in the

Re: [Haskell-cafe] Re: Overloading functions based on arguments?

Hi Table is a table of name-value pairs I want to substitute in a tree-like structure using: substitute :: Table - Tree - Tree For substituting a single name-value pair I want to define this utitlity routine so I don't have to construct a Table all the time in the user code: substitute

[Haskell-cafe] createProcess shutting file handles

Hi, I want to run multiple programs and dump the stdout/stderr to a file, I've tried doing: h - openFile file WriteMode let c = CreateProcess (RawCommand file []) Nothing Nothing Inherit (UseHandle h) (UseHandle h) False (_,_,_,pid)

Re: [Haskell-cafe] Re: Overloading functions based on arguments?

Hi Chances are the program you're using to write your e-mails was written in C++ (or at least C), so don't knock it. :-) Firefox (Javascript + C++) and Gmail (Python, so I think I read, no doubt with C underneath somewhere). However, I am sat writing C++ at the moment - which I think gives me

Re: [Haskell-cafe] Happstack 0.1 Released!

Hi Successor as in Happstack replaces HAppS entirely and all projects implemented in HAppS should aim to port to Happstack - or successor as in builds on the ideas in HAppS? Is HAppS now deprecated? Thanks Neil 2009/2/4 Matthew Elder m...@mattelder.org: Hello Haskell Cafe, I just wanted to

Re: [Haskell-cafe] Re: 1,000 packages, so let's build a few!

Hi GHC doesn't bundle with cabal-install on any system. What is needed is not for the GHC team to be doing Windows platform packages, but for the Windows Haskell devs to build their own system, as happens on all the Unices. Take GHC's release, wrap it up with native installers, throw in

Re: [Haskell-cafe] Re: 1,000 packages, so let's build a few!

Hi So actually just having more Windows users subscribed to cabal-devel and commenting on tickets would be very useful, even if you do not have much time for hacking. I believe that as soon as a Windows user starts doing that you'll start asking them for patches :-) There are a number of

Re: [Haskell-cafe] The case of the missing Arrow function

Hi Henk, You're only a Hoogle away: http://haskell.org/hoogle/?hoogle=liftA2 Control.Applicative liftA2 :: Applicative f = (a - b - c) - f a - f b - f c I guess its both an arrow function and an applicative function. Thanks Neil On Fri, Jan 30, 2009 at 3:02 PM, Henk-Jan van Tuyl

Re: [Haskell-cafe] Re: How outdated is Hugs?

Hi to mind), if Hugs is likely to continue to have compatibility problems with GHC, then is there any way an interface similar to that already available for WinHugs could be created for GHCi? If that gets underway, one additional improvement could be to improve the REPL at handling declared

Re: [Haskell-cafe] Re: Liskell installation configuration problems in Cygwin on Windows XP Professional, Service Pack 2

Hi Benjamin, Try: cabal install ghc-paths If you want to install packages manually you can also get it from http://hackage.haskell.org Thanks Neil On Fri, Jan 23, 2009 at 9:16 AM, Benjamin L. Russell dekudekup...@yahoo.com wrote: On Fri, 23 Jan 2009 18:10:16 +0900, Benjamin L.Russell

Re: [Haskell-cafe] Expect module?

Hi Erik, Is there a Haskell-Expect module? Something that would allow me to control an external Unix program via its stdin/stdout/stderr? System.Process does what you want, I think: http://hackage.haskell.org/packages/archive/process/1.0.1.1/doc/html/System-Process.html Thanks Neil

Re: [Haskell-cafe] ANN: HLint 1.2

Hi Henning, To install: cabal update cabal install hlint Fails for me, because of the base-4 dependency. - I'm still using GHC-6.8.2. Can HLint suggest view-pattern-free expressions, such that the program also runs on GHC-6.8 ? :-) HLint is written using view-patterns so requires GHC 6.10

Re: [Haskell-cafe] ANN: HLint 1.2

Hi My question was, whether HLint can help translating HLint to code without view patterns. Ah, I misunderstood. Yes, it could (in theory), but it can't automatically apply the hints it generates. Upgrading to GHC 6.10 is probably easier :-) Thanks Neil

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