[Haskell-cafe] CABAL: conditional executable?
I'm putting together a package consisting of 2 executables. Only one of them is pure Haskell and thus buildable on all platforms, the other relies on Windows API calls and can only be built on that platform. I found the “if os(...)” conditional in the CABAL docs but I'm having problems getting it to do what I want. if os(mingw32) executable foo ... Results in the error “Section expected”. Swapping the two lines like this executable foo if os(mingw32) ... results in “Setup.hs: Error: No 'Main-Is' field found for executable foo”. Is there a way to get CABAL to do what I want or should I raise a feature request on the CABAL trac? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus．therning＠gmail．com http://therning.org/magnus What if I don't want to obey the laws? Do they throw me in jail with the other bad monads? -- Daveman signature.asc Description: OpenPGP digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] CABAL: conditional executable?
executable foo main-is: bla if !os(windows): buildable: false Unfortunately this gives rather unhelpful error messages when used with flags, but it works well enough for now. / Thomas On 4 mar 2008, at 09.10, Magnus Therning wrote: I'm putting together a package consisting of 2 executables. Only one of them is pure Haskell and thus buildable on all platforms, the other relies on Windows API calls and can only be built on that platform. I found the “if os(...)” conditional in the CABAL docs but I'm having problems getting it to do what I want. if os(mingw32) executable foo ... Results in the error “Section expected”. Swapping the two lines like this executable foo if os(mingw32) ... results in “Setup.hs: Error: No 'Main-Is' field found for executable foo”. Is there a way to get CABAL to do what I want or should I raise a feature request on the CABAL trac? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus．therning＠ gmail．com http://therning.org/magnus What if I don't want to obey the laws? Do they throw me in jail with the other bad monads? -- Daveman ___ 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] CABAL: conditional executable?
On Tue, 4 Mar 2008, Magnus Therning wrote: I'm putting together a package consisting of 2 executables. Only one of them is pure Haskell and thus buildable on all platforms, the other relies on Windows API calls and can only be built on that platform. I found the âif os(...)â conditional in the CABAL docs but I'm having problems getting it to do what I want. if os(mingw32) executable foo ... Results in the error âSection expectedâ. Swapping the two lines like this executable foo if os(mingw32) ... results in âSetup.hs: Error: No 'Main-Is' field found for executable fooâ. It sounds like another instance of the case that parts of a package cannot be build under some circumstances. Keep in mind that other packages might rely on the installed second executable if they find that the package is installed. Thus, I guess it's better to extract the second executable to a different package for Window's only stuff.___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] CABAL: conditional executable?
On 3/4/08, Henning Thielemann [EMAIL PROTECTED] wrote: On Tue, 4 Mar 2008, Magnus Therning wrote: I'm putting together a package consisting of 2 executables. Only one of them is pure Haskell and thus buildable on all platforms, the other relies on Windows API calls and can only be built on that platform. I found the â if os(...)â conditional in the CABAL docs but I'm having problems getting it to do what I want. if os(mingw32) executable foo ... Results in the error â Section expectedâ . Swapping the two lines like this executable foo if os(mingw32) ... results in â Setup.hs: Error: No 'Main-Is' field found for executable fooâ . It sounds like another instance of the case that parts of a package cannot be build under some circumstances. Keep in mind that other packages might rely on the installed second executable if they find that the package is installed. Thus, I guess it's better to extract the second executable to a different package for Window's only stuff. Good point. Does CABAL 1.2 have support for multiple .cabal files in the same directory? If not then I'm not too happy with this solution. /M ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] CABAL: conditional executable?
On 4 mar 2008, at 10.58, Magnus Therning wrote: Good point. Does CABAL 1.2 have support for multiple .cabal files in the same directory? If not then I'm not too happy with this solution. No. Eventually, Cabal will support something like this, but it's unlikely that Cabal 1.4 will. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] CABAL: conditional executable?
On 3/4/08, Thomas Schilling [EMAIL PROTECTED] wrote: executable foo main-is: bla if !os(windows): buildable: false Unfortunately this gives rather unhelpful error messages when used with flags, but it works well enough for now. / Thomas Hmmm, I don't seem to get this to work the way I want it. I get a Parse of field 'buildable' failed: which means configure failed and then I can't proceed to build the second executable, bar, in the same package. /M ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Doubting Haskell
Alan Carter wrote: I've written up some reflections on my newbie experience together with both versions, which might be helpful to people interested in popularizing Haskell, at: http://the-programmers-stone.com/2008/03/04/a-first-haskell-experience/ Thank you for writing this. On the lack of simple examples showing, for example, file IO: I seem to recall a Perl book (maybe it was Edition 1 of the Camel Book) which had lots of very short programs each illustrating one typical job. Also the Wiki does have some pages of worked example programs. But I agree, we could do better. I'm surprised you found the significant whitespace difficult. Yes, the formal rules are a bit arcane, but I just read them as does the Right Thing, and it generally works for me. I didn't know about the significance of comments, but then I've never written an outdented comment. I had a look through your code, and although I admit I haven't done the work, I'm sure that there would be ways of factoring out all the commonality and thereby reducing the length. Finally, thanks for that little story about the BBC B. I had one of those, and I always wondered about that heatsink, and the stonking big resistor next to it. They looked out of scale with the rest of the board. Paul. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] CABAL: conditional executable?
On 4 mar 2008, at 11.37, Magnus Therning wrote: On 3/4/08, Thomas Schilling [EMAIL PROTECTED] wrote: executable foo main-is: bla if !os(windows): buildable: false Unfortunately this gives rather unhelpful error messages when used with flags, but it works well enough for now. / Thomas Hmmm, I don't seem to get this to work the way I want it. I get a Parse of field 'buildable' failed: which means configure failed and then I can't proceed to build the second executable, bar, in the same package. Oh, right. That's a bug in Cabal 1.2 (fixed in HEAD). Use: buildable: False HTH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Doubting Haskell
Paul Johnson [EMAIL PROTECTED] writes: I'm surprised you found the significant whitespace difficult. I wonder if this has something to do with the editor one uses? I use Emacs, and just keep hitting TAB, cycling through possible alignments, until things align sensibly. I haven't really tried, but I can imagine lining things up manually would be more painful, especially if mixing tabs and spaces. -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] Doubting Haskell
On Tue, Mar 4, 2008 at 4:16 AM, Ketil Malde [EMAIL PROTECTED] wrote: Paul Johnson [EMAIL PROTECTED] writes: I'm surprised you found the significant whitespace difficult. I wonder if this has something to do with the editor one uses? I use Emacs, and just keep hitting TAB, cycling through possible alignments, until things align sensibly. I haven't really tried, but I can imagine lining things up manually would be more painful, especially if mixing tabs and spaces. Especially if mixing tabs and spaces indeed. Haskell does the Python thing of assuming that a tab is 8 spaces, which IMO is a mistake. The sensible thing to do if you have a whitespace-sensitive language that accepts both spaces in tabs is to make them incomparable to each other; i.e. main = do spspputStrLn $ Hello spsptab++ World -- compiles fine main = do spspputStrLn $ Hello tab++ World -- error, can't tell how indented '++ World' is... Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Markup bug in HaskellWiki
In the Wiki article http://haskell.org/haskellwiki/Comparison_chain there is the piece unzipunzip which is improperly formatted. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Markup bug in HaskellWiki
On 04/03/2008, Henning Thielemann [EMAIL PROTECTED] wrote: In the Wiki article http://haskell.org/haskellwiki/Comparison_chain there is the piece unzipunzip which is improperly formatted. I guess the wiki uses GeSHi, and it's because of a bug in the keyword list. I reported it to the maintainer a few weeks ago (when I wrote this [1]) but I haven't heard any word back. It's dead easy to fix if someone has access to the PHP source. There's a file called, IIRC, haskell.php with a large list of keywords. Two of them, 'unzip' and 'unzip3' appear twice. Delete one of each and it all works fine again. [1] http://www.dougalstanton.net/blog/index.php/2008/02/12/spot-the-deliberate-mistake -- Dougal Stanton [EMAIL PROTECTED] // http://www.dougalstanton.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Doubting Haskell
On 04/03/2008, Alan Carter [EMAIL PROTECTED] wrote: http://the-programmers-stone.com/2008/03/04/a-first-haskell-experience/ That was an interesting read. Thanks for posting it. I also liked the tale of the BBC ULA - it reminded me of a demo I saw once at an Acorn show, where they had a RISC PC on show, with a (IBM) PC card in it. They were demonstrating how hot the PC chip runs compared to the ARM RISC chip by using it to make toast. I dread to think what you could do with one of today's monsters :-) Paul. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Connection helpers: for people interested in network code
On Fri, Feb 29, 2008 at 8:50 PM, Adam Langley [EMAIL PROTECTED] wrote: I generally find that I'm wrapping sockets in the same functions a lot and now I'm looking writings code which works with both Sockets and SSL connections. So I wrote a module, presumptuously called Network.Connection, although I'm not actually going to try and take that name (even in Hackage) unless I get a general agreement that this is a good thing. So, any comments on the interface, similar things that I should look at etc? http://www.imperialviolet.org/binary/network-connection/Network-Connection.html I made the BaseConnection an ADT, rather than a class because I wanted to avoid hitting the monomorphism restriction in code. That might have been a mistake, I'm not sure yet. If it doesn't excite anyone enough to reply, I'll change the name and put it in Hackage, mostly as is. Then I'll tie HsOpenSSL into it so that SSL connections work transparently. Hi Adam, you may want to have a look at the socket abstraction used in the HTTP package: http://hackage.haskell.org/packages/archive/HTTP/3001.0.4/doc/html/Network-Stream.html It would be great to get HTTPS support going! /Bjorn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] problem in using wash
Hi, I was trying to use wash to learn it. I am using ubuntu and I have ghc6.6.1 installed on my system. I have also installed the package libghc6-wash-dev but in my code when i write import WASH.CGI it gives me following error firstCGI.hs:5:7: Could not find module `WASH.CGI': locations searched: WASH/CGI.hs WASH/CGI.lhs Failed, modules loaded: none. can somebody help me in this? Regards, Vikrant ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Connection helpers: for people interested in network code
On Tue, Mar 4, 2008 at 7:31 AM, Bjorn Bringert [EMAIL PROTECTED] wrote: you may want to have a look at the socket abstraction used in the HTTP package: http://hackage.haskell.org/packages/archive/HTTP/3001.0.4/doc/html/Network-Stream.html It would be great to get HTTPS support going! I should have mentioned that I had seen this in the original email. I think the major problem with this interface was that it was written in the time before ByteStrings. Now that we have ByteStrings I think that it makes a lot of sense for networking to use them. However, it shouldn't be too hard to wrap HsOpenSSL in this interface. I might try this this week. Then HTTPS should Just Work (maybe ;) AGL -- Adam Langley [EMAIL PROTECTED] http://www.imperialviolet.org ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Markup bug in HaskellWiki
Am Dienstag, 4. März 2008 16:10 schrieb Dougal Stanton: […] There's a file called, IIRC, haskell.php with a large list of keywords. Two of them, 'unzip' and 'unzip3' appear twice. Delete one of each and it all works fine again. Why do they appear at all? They are not keywords. Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Doubting Haskell
On 04/03/2008, Luke Palmer [EMAIL PROTECTED] wrote: On Tue, Mar 4, 2008 at 4:16 AM, Ketil Malde [EMAIL PROTECTED] wrote: Paul Johnson [EMAIL PROTECTED] writes: I'm surprised you found the significant whitespace difficult. I wonder if this has something to do with the editor one uses? I use Emacs, and just keep hitting TAB, cycling through possible alignments, until things align sensibly. I haven't really tried, but I can imagine lining things up manually would be more painful, especially if mixing tabs and spaces. Especially if mixing tabs and spaces indeed. Haskell does the Python thing of assuming that a tab is 8 spaces, which IMO is a mistake. The sensible thing to do if you have a whitespace-sensitive language that accepts both spaces in tabs is to make them incomparable to each other; i.e. snip I honestly think that tab characters occurring anywhere but in a comment should be considered a lexical error and rejected by the compiler outright. More problems are caused by trying to continue with only tabs, or some mixture of tabs and spaces than just getting one's editor to expand tabs automatically. - Cale ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Annotating GHC assembler output?
On Mon, Mar 3, 2008 at 5:41 PM, Ben Lippmeier [EMAIL PROTECTED] wrote: Hi Justin. try: ghc -c file -ddump-to-file -ddump-asm Thanks, that does it. I also tried the -keep-s-files (possibly new to 6.8) and found it produces the same output. Justin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Markup bug in HaskellWiki
On Tue, 4 Mar 2008, Wolfgang Jeltsch wrote: Am Dienstag, 4. März 2008 16:10 schrieb Dougal Stanton: […] There's a file called, IIRC, haskell.php with a large list of keywords. Two of them, 'unzip' and 'unzip3' appear twice. Delete one of each and it all works fine again. Why do they appear at all? They are not keywords. They link to the online Haddock documentation of Prelude. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Markup bug in HaskellWiki
On 04/03/2008, Wolfgang Jeltsch [EMAIL PROTECTED] wrote: Am Dienstag, 4. März 2008 16:10 schrieb Dougal Stanton: […] There's a file called, IIRC, haskell.php with a large list of keywords. Two of them, 'unzip' and 'unzip3' appear twice. Delete one of each and it all works fine again. Why do they appear at all? They are not keywords. Well, keywords is a bit of a misnomer. Geshi isn't very smart, it just recognises the standard prelude and adds in links to the online API. D -- Dougal Stanton [EMAIL PROTECTED] // http://www.dougalstanton.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Functional programmer's intuition for adjunctions?
Hi, Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). Thanks, Edsko ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] (flawed?) benchmark : sort
2008/3/4, Krzysztof Skrzętnicki [EMAIL PROTECTED]: Hi I was playing with various versions of sorting algorithms. I know it's very easy to create flawed benchmark and I don't claim those are good ones. However, it really seems strange to me, that sort - library function - is actually the worse measured function. I can hardly belive it, and I'd rather say I have made a mistake preparing it. The overall winner seems to be qsort_iv - which is nothing less but old sort replaced by mergesort now. Any clues? Part of what you may be missing : -- cut here -- module Main where import Control.Parallel.Strategies import Control.Arrow import System.CPUTime import System.IO import System.Environment import System.Random import Data.List( partition, sort ) data Tree a = Node (Tree a) a (Tree a) | Leaf qsort_i [] = [] qsort_i (x:xs) = qsort_i (filter ( x) xs) ++ [x] ++ qsort_i (filter (= x) xs) qsort_ii [] = [] qsort_ii (x:xs) = let (ls,gt) = partition ( x) xs in qsort_ii ls ++ [x] ++ qsort_ii gt qsort_iii xs = qsort_iii' [] xs qsort_iii' acc [] = acc qsort_iii' acc (x:xs) = let (ls,gt) = partition ( x) xs in let acc' = (x:(qsort_iii' acc gt)) in qsort_iii' acc' ls qsort_v [] = [] qsort_v (x:xs) = let (xlt, xgt ) = foldl (\ (lt,gt) el - case compare x el of GT - (el:lt, gt) _ - (lt, el:gt) ) ([],[]) xs in qsort_v xlt ++ [x] ++ qsort_v xgt -- zmodyfikowany i qsort_vi [] = [] qsort_vi (x:xs) = qsort_vi (filter (\y- compare x y == GT) xs) ++ [x] ++ qsort_vi (filter (\y- compare x y /= GT) xs) -- zmodyfikowany iii qsort_vii xs = qsort_vii' [] xs qsort_vii' acc [] = acc qsort_vii' acc (x:xs) = let (ls,gt) = partition (\y- compare x y == GT) xs in let acc' = (x:(qsort_vii' acc gt)) in qsort_vii' acc' ls -- qsort is stable and does not concatenate. qsort_iv xs = qsort_iv' (compare) xs [] qsort_iv' _ [] r = r qsort_iv' _ [x]r = x:r qsort_iv' cmp (x:xs) r = qpart cmp x xs [] [] r -- qpart partitions and sorts the sublists qpart cmp x [] rlt rge r = -- rlt and rge are in reverse order and must be sorted with an -- anti-stable sorting rqsort_iv' cmp rlt (x:rqsort_iv' cmp rge r) qpart cmp x (y:ys) rlt rge r = case cmp x y of GT - qpart cmp x ys (y:rlt) rge r _ - qpart cmp x ys rlt (y:rge) r -- rqsort is as qsort but anti-stable, i.e. reverses equal elements rqsort_iv' _ [] r = r rqsort_iv' _ [x]r = x:r rqsort_iv' cmp (x:xs) r = rqpart cmp x xs [] [] r rqpart cmp x [] rle rgt r = qsort_iv' cmp rle (x:qsort_iv' cmp rgt r) rqpart cmp x (y:ys) rle rgt r = case cmp y x of GT - rqpart cmp x ys rle (y:rgt) r _ - rqpart cmp x ys (y:rle) rgt r -- code by Orcus -- Zadanie 9 - merge sort mergeSort :: Ord a = [a] - [a] mergeSort []= [] mergeSort [x] = [x] mergeSort xs= let(l, r) = splitAt (length xs `quot` 2) xs in mergeSortP (mergeSort l) (mergeSort r) -- funkcja pomocnicza scalajÄ…ca dwie listy uporzÄ…dkowane w jednÄ… mergeSortP :: Ord a = [a] - [a] - [a] mergeSortP xs []= xs mergeSortP [] ys= ys mergeSortP (x:xs) (y:ys) | x = y = x:(mergeSortP xs (y:ys)) | otherwise = y:(mergeSortP (x:xs) ys) -- Zadanie 10 - tree sort treeSort :: Ord a = [a] - [a] -- pointless po raz drugi treeSort = (treeSortInorder . treeSortToTree) treeSortToTree :: Ord a = [a] - Tree a treeSortToTree [] = Leaf treeSortToTree (x:xs) = let (xlt, xgt) = foldl (\ (lt,gt) el - case compare x el of GT - (el:lt, gt) _ - (lt, el:gt) ) ([],[]) xs in Node (treeSortToTree xlt) x (treeSortToTree xgt) treeSortInorder :: Ord a = Tree a - [a] treeSortInorder Leaf= [] treeSortInorder (Node l x r)= (treeSortInorder l) ++ [x] ++ (treeSortInorder r) -- end code by Orcus -- begin benchmark making code makeBenchs benchs xs = do let (funcNames, funcs) = unzip benchs tBegin - getCPUTime timers - mapM (\f- print (f xs) getCPUTime) funcs let times = zipWith (-) timers (tBegin:timers) sortedResults = sort $ zip times funcNames minT = fromIntegral $ fst $ head sortedResults scaled = map (((/minT) . fromIntegral) *** id) sortedResults hPutStr stderr $ unlines $ map show scaled onRandom eltCnt = do gen - getStdGen let xs = take eltCnt (randomRs (1::Int, bigNum) gen) `using` rnf xs `seq` return xs onSorted eltCnt = do gen - getStdGen let xs = take eltCnt (randomRs (1::Int, bigNum) gen) `using` rnf sxs = sort xs `using` rnf xs `seq` sxs `seq` return sxs bigNum = 100 :: Int -- end of benchmark making code main = makeBenchs [(i,qsort_i), (ii,qsort_ii), (iii,qsort_iii), (iv,qsort_iv),
Re: [Haskell-cafe] (flawed?) benchmark : sort
Hi -- Zadanie 9 - merge sort mergeSort :: Ord a = [a] - [a] mergeSort []= [] mergeSort [x] = [x] mergeSort xs= let(l, r) = splitAt (length xs `quot` 2) xs in mergeSortP (mergeSort l) (mergeSort r) splitAt is not a particularly good way to split a list, since you recurse over the list twice. Try instead: split (x:xs) = (x:b,a) where (a,b) = split xs split [] = ([], []) Perhaps adding some strictness annotations and turning the where into a case. Also remember that a standard benchmark for sorting is an ordered/reverse ordered list, as that causes quicksort to go to O(n^2) given a bad pivot choice. If the sort in the standard libraries can be improved on, it should be replaced. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional programmer's intuition for adjunctions?
On Tue, 2008-03-04 at 17:16 +, Edsko de Vries wrote: Hi, Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). Well when you pretend Hask is Set, many things can be discussed fairly directly. F is left adjoint to U, F -| U, if Hom(FA,B) is naturally isomorphic to Hom(A,UB), natural in A and B. A natural transformation over Set is just a polymorphic function. So we have an adjunction if we have two functions: phi :: (F a - b) - (a - U b) and phiInv :: (a - U b) - (F a - b) such that phi . phiInv = id and phiInv . phi = id and F and U are instances of Functor. The unit and counit respectively is then just phi id and phiInv id. You can work several examples using this framework, though it gets difficult when it is difficult to model other categories. Also discussing and proving some properties of adjunctions (namely continuity properties) would help. Of course, this is a concrete example using basic ideas of programming and not some intuitive analogy. I feel comfortable working with adjunctions, but I don't have some general analogy that I use. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional programmer's intuition for adjunctions?
On Tue, Mar 04, 2008 at 11:58:38AM -0600, Derek Elkins wrote: On Tue, 2008-03-04 at 17:16 +, Edsko de Vries wrote: Hi, Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). Well when you pretend Hask is Set, many things can be discussed fairly directly. F is left adjoint to U, F -| U, if Hom(FA,B) is naturally isomorphic to Hom(A,UB), natural in A and B. A natural transformation over Set is just a polymorphic function. So we have an adjunction if we have two functions: phi :: (F a - b) - (a - U b) and phiInv :: (a - U b) - (F a - b) such that phi . phiInv = id and phiInv . phi = id and F and U are instances of Functor. The unit and counit respectively is then just phi id and phiInv id. Sure, but that doesn't really explain what an adjunction *is*. For me, it helps to think of a natural transformation as a polymorphic function: it gives me an intuition about what a natural transformation is. Specializing the definition of an adjunction for Hask (or Set) helps understanding the *definitions*, but not the *intention*, if that makes any sense.. Edsko ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional programmer's intuition for adjunctions?
Well, we have at least one very useful example of adjunction. It's called curry. See, if X is some arbitrary type, you can define type F = (,X) instance Functor F where fmap f (a,x) = (fa,x) type G = (-) X instance Functor G where fmap f h = \x - f (h x) Now, we have the adjunction: phi :: ((a,X) - b) - (a - (X - b)) phi = curry phiInv :: (a - (X - b)) - ((a,X) - b) phiInv = uncurry On 4 Mar 2008, at 21:30, Edsko de Vries wrote: On Tue, Mar 04, 2008 at 11:58:38AM -0600, Derek Elkins wrote: On Tue, 2008-03-04 at 17:16 +, Edsko de Vries wrote: Hi, Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). Well when you pretend Hask is Set, many things can be discussed fairly directly. F is left adjoint to U, F -| U, if Hom(FA,B) is naturally isomorphic to Hom(A,UB), natural in A and B. A natural transformation over Set is just a polymorphic function. So we have an adjunction if we have two functions: phi :: (F a - b) - (a - U b) and phiInv :: (a - U b) - (F a - b) such that phi . phiInv = id and phiInv . phi = id and F and U are instances of Functor. The unit and counit respectively is then just phi id and phiInv id. Sure, but that doesn't really explain what an adjunction *is*. For me, it helps to think of a natural transformation as a polymorphic function: it gives me an intuition about what a natural transformation is. Specializing the definition of an adjunction for Hask (or Set) helps understanding the *definitions*, but not the *intention*, if that makes any sense.. Edsko ___ 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: Functional programmer's intuition for adjunctions?
Well, we have at least one very useful example of adjunction. It's called curry. See, if X is some arbitrary type, you can define This adjunction is the one that makes a category cartesian closed. Dominic. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell Perl architecture question
I'm looking at a production system running Perl Haskell in an Apache environment and trying to get a handle on the system architecture. Are there online resources anyone could recommend I start with? Thanks in advance, Marty -- Marty Landman, Face 2 Interface Inc. 845-679-9387 Drupal Development Blog: http://drupal.face2interface.com/ Free Database Search App: http://face2interface.com/Products/FormATable.shtml ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional programmer's intuition for adjunctions?
Edsko asked: Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). I think there's a catch because many interesting examples of adjunctions involve multiple distinct categories. So there's a sense in which you have to go outside of programming to explain what they are, apart from a few simple examples like currying. But if you're familiar with the category of monoids and monoid homomorphisms, then we can generate another example: One intuition is the notion of trying to approximate an object in one category using objects in another. For example, consider the category of monoids. How best can we approximate an arbitrary type in a monoid? Suppose our type, T, has elements a,b and c. We could try to represent this as a monoid. But monoids should have products and an identity. So if the monoid contains a,b and c it should also contain 1, ab, bc, abcba and so on. And what should ab equal? Might it be the same as bc? The simplest strategy is to assume that all of these products are distinct and approximate the type T with the monoid containing 1, a, b and c and assuming no element equals any other unless the monoid laws say so (ie. 1a=a1=a). This is called the *f*ree monoid generated by T, and we can write it F(T). Now go the other way: given a monoid, S, how can we map it back to a type? There's an obvious idea, just make a type whose elements are the *u*nderlying elements of the monoid, discarding the multiplication rule. Call this U(S). (We're treating Hask like Set here.) So what's U(F(T))? T gets mapped to the free monoid generated by T, and mapped back to the elements of this monoid. In other words, the elements of U(F(T)) are (possibly non-empty) strings of elements of T. So UF is the list type constructor. Any homomorphism, f, between monoids is completely determined once you know where a set of generators of the monoid map under the homomorphism, and vice versa. All of the other elements can be deduced using f(1) = 1 and f(xy)=f(x)f(y). So if F(a) is the free monoid generated by a, then a homomorphism F(a)-b is completely determined by a function a-U(b), and vice versa. We have an isomorphism (F(a)-b) - (a-U(b)) and (F,U) forms an adjunction, according to Derek's definition. So intuitively, what's going on is that Haskell lists emerge as a result of an attempt to approximate types with monoids and adjunctions formalise what we mean by 'approximation'. When we go from a type, to a monoid, and back again, we don't end up where we started, but at a new type. Other adjunctions can be seen in this way. But because different examples use different categories, it's hard to picture a uniform way of viewing adjunctions that spans them all. It's also no coincidence now that lists form a monad... -- Dan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Doubting Haskell
About the line length needed for Haskell programs, there was a discussion about this some time ago, that could be regarded as a tutorial for reducing indentation: http://haskell.org/pipermail/haskell-cafe/2007-July/028787.html As for the idle core you mention: I keep one core fully occupied with a program that searches for a cure against cancer, see: http://www.computeagainstcancer.org/ The example you gave for the use of map can be simplified: map func (take (10 [0..])) -- should actually be: map func (take 10 [0..]) - map func [0..9] Regards, Henk-Jan van Tuyl -- http://functor.bamikanarie.com http://Van.Tuyl.eu/ -- On Tue, 04 Mar 2008 07:29:24 +0100, Alan Carter [EMAIL PROTECTED] wrote: Many thanks for the explanations when I was first experimenting with Haskell. I managed to finish translating a C++ wxWidgets program into Haskell wxHaskell, and am certainly impressed. I've written up some reflections on my newbie experience together with both versions, which might be helpful to people interested in popularizing Haskell, at: http://the-programmers-stone.com/2008/03/04/a-first-haskell-experience/ Regards, Alan -- -- Met vriendelijke groet, Henk-Jan van Tuyl -- http://functor.bamikanarie.com http://Van.Tuyl.eu/ -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Perl architecture question
Not quite sure what you're looking for? Do you mean that you're looking at the possibility of setting such a system up, or that you're looking at a system that is already set up and trying to grok how it works? If the latter, you might want to get a sense of how ghc manages its packages and dependencies at http://www.haskell.org/ghc/docs/latest/html/users_guide/packages.html, which also includes links to the information on the cabal infrastructure. If that's not your question, then that material might either be too basic for you or too offbase. The GHC manual is generally very well documented in terms of describing package infrastructure, the linking process and the runtime environment, etc. If, rather, you're looking at issues more directly related to Haskell/web stuff, you might want to specify what exactly you're looking to do, as there are a number of solutions in use rather than a single, e.g., mod_haskell. If it's an established system, then either it will be using a haskell webserver (WASH, HAppS, etc) or it will be written using the CGI/FastCGI libraries. If you're looking to set up a system, then of course it depends what you want to do with it... for lightweight solutions, a combination of FastCGI and HDBC seems to be pretty popular at the moment. In all these cases, note that generally you'll be working with Haskell binaries, rather than scripts, and that such binaries should either be built on the system in question directly, or on one with the same architecture. Hope that helps, Sterl. On Tue, Mar 4, 2008 at 2:06 PM, Marty Landman [EMAIL PROTECTED] wrote: I'm looking at a production system running Perl Haskell in an Apache environment and trying to get a handle on the system architecture. Are there online resources anyone could recommend I start with? Thanks in advance, Marty -- Marty Landman, Face 2 Interface Inc. 845-679-9387 Drupal Development Blog: http://drupal.face2interface.com/ Free Database Search App: http://face2interface.com/Products/FormATable.shtml ___ 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] Doubting Haskell
2008/3/4, Alan Carter [EMAIL PROTECTED]: I've written up some reflections on my newbie experience together with both versions, which might be helpful to people interested in popularizing Haskell, at: http://the-programmers-stone.com/2008/03/04/a-first-haskell-experience/ This is truly interesting, any learning experience is enlightening, we truly do need to lower this barrier of admittance of which you speak. On another subject, there are still point in your code that could be clearer or done with less cruft : maxOfHistogram stats = snd (foldl (\(cA, vA) (cB, vB) - if (vA vB) then (cA, vA) else (cB, vB)) (0, 0) stats) can become : maxofHistogram stats = foldl' max 0 (map snd stats) (foldl' max 0 could be replaced by maximum but there wouldn't be a default 0 anymore) more importantly, you can replace this kind of code : vA - varCreate [] vB - varCreate [] -- ... vL - varCreate [] vM - varCreate [] vN - varCreate [] vO - varCreate [] by : [vA, vB, vC, vD, vE, vF, vG, vH, vI, vJ, vK, vL, vM, vN, vO] - replicateM 15 (varCreate []) (true also for the dA - textEntry statusFrame [text := 0, alignment := AlignRight] sequence) I'm not sure that functions like getdTotal couldn't be improved, I wonder if a small Map for the elements of d wouldn't make the code much better and offer other opportunities for abstractions. As it is, enumeration like : [[label Total Entries, widget (getdTotal d)] ,[label Valid Entries, widget (getdValid d)] -- ... ,[label MDMA,widget (getdMdma d)] ,[label Caffeine,widget (getdCaffeine d)]] could be slightly reduced by : let bindLabelAndWidget (lbl,getter) = [label lbl, widget (getter d)] in map bindLabelAndWidget [(Total Entries, getdTotal), (Valid Entries, getdValid) ,(...)] And little thing like : mapM_ (\f - do repaint f) knownFrames becoming : mapM_ repaint knownFrames I also do concur that a flag or a warning to signal mixed tabulations and space would be a _very_ good idea ! -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] (flawed?) benchmark : sort
Thanks for improved code. My point was to measure which programming patterns are faster than the others so I can learn which ones I should use. However, the thing that is really bad is the fact, that even oneliner qsort_i is faster than library sort. Which is very different from what I've expected. My intuition is only best and fastest code goes to library, to the point that people can learn from it. It seems I was mislead. It could probably be improved (with classics solution (better selection of the pivot...)), but the mergesort is only 3 times slower in worse case, and much more regular, if someone needs a faster sort in a specific case, it isn't hard to code. -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] (flawed?) benchmark : sort
2008/3/4, Krzysztof Skrzętnicki [EMAIL PROTECTED]: Thanks for improved code. My point was to measure which programming patterns are faster than the others so I can learn which ones I should use. However, the thing that is really bad is the fact, that even oneliner qsort_i is faster than library sort. Which is very different from what I've expected. My intuition is only best and fastest code goes to library, to the point that people can learn from it. It seems I was mislead. I think you did not correctly got the point of my and Neil Mitchell's message : you benchmarked those function on a completely random sequences so qsort was at his best, but in the real world, most sequences would have bias, and it is not infrequent at all to sort a partially sorted (or reverse sorted) list... In this case the performance of all your qsort are abysmal... Which is the reason the old sort was replaced by the actual mergesort in the library. Try my code (with 1 elements for example), you'll see that sort is the best on a sorted list, and that qsort is at least 60 times slower (on 1, in fact it is degenerating in O(n^2)). In the real world, the library maintainers decided it was ok to pay a slight overhead in the case where the list to sort is really randomly distributed since mergesort won so hugely over qsort in the pretty frequent case (in programs) of lists which present regularities. There is no sort which is ideal in all situations, but we can try to get a sort that works well in all situations, and don't trash in situations not so infrequent. (On the other hand, don't expect libraries functions to always be the best to use in your particular situation, they tend to be all-purpose as we just saw and the maintainers prefer simple generic implementations rather than complicated ones who could be slightly (or even significantly) faster in some case) -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: problem in using wash
Vikrant [EMAIL PROTECTED] writes: I was trying to use wash to learn it. I am using ubuntu and I have ghc6.6.1 installed on my system. I have also installed the package libghc6-wash-dev but in my code when i write import WASH.CGI it gives me following error firstCGI.hs:5:7: Could not find module `WASH.CGI': locations searched: WASH/CGI.hs WASH/CGI.lhs Failed, modules loaded: none. can somebody help me in this? Check with 'ghc-pkg list' if the package is present, then use 'ghc-pkg describe WashNGo' to get the exported module names. Also don't forget to use --make when compiling (or explicit package name). -- Regards, Feri. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] (flawed?) benchmark : sort
I get it now, thanks. Also, I guess it is possible to find a better algorithm for standard library sort. Christopher Skrzętnicki On Wed, Mar 5, 2008 at 12:04 AM, Chaddaï Fouché [EMAIL PROTECTED] wrote: 2008/3/4, Krzysztof Skrzętnicki [EMAIL PROTECTED]: Thanks for improved code. My point was to measure which programming patterns are faster than the others so I can learn which ones I should use. However, the thing that is really bad is the fact, that even oneliner qsort_i is faster than library sort. Which is very different from what I've expected. My intuition is only best and fastest code goes to library, to the point that people can learn from it. It seems I was mislead. I think you did not correctly got the point of my and Neil Mitchell's message : you benchmarked those function on a completely random sequences so qsort was at his best, but in the real world, most sequences would have bias, and it is not infrequent at all to sort a partially sorted (or reverse sorted) list... In this case the performance of all your qsort are abysmal... Which is the reason the old sort was replaced by the actual mergesort in the library. Try my code (with 1 elements for example), you'll see that sort is the best on a sorted list, and that qsort is at least 60 times slower (on 1, in fact it is degenerating in O(n^2)). In the real world, the library maintainers decided it was ok to pay a slight overhead in the case where the list to sort is really randomly distributed since mergesort won so hugely over qsort in the pretty frequent case (in programs) of lists which present regularities. There is no sort which is ideal in all situations, but we can try to get a sort that works well in all situations, and don't trash in situations not so infrequent. (On the other hand, don't expect libraries functions to always be the best to use in your particular situation, they tend to be all-purpose as we just saw and the maintainers prefer simple generic implementations rather than complicated ones who could be slightly (or even significantly) faster in some case) -- Jedaï ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Functional programmer's intuition for adjunctions?
On Tue, 2008-03-04 at 19:01 +, Dominic Steinitz wrote: Well, we have at least one very useful example of adjunction. It's called curry. See, if X is some arbitrary type, you can define This adjunction is the one that makes a category cartesian closed. and the monad for it gives rise to the state monad. And the other adjunction relating to exponentials and symmetry gives rise to the continuation monad. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Yhc] Yhc Web Service quietly opened for public testing
That is seriously cool. Congratulations Dmitry! thomas. 2008/3/4, Dimitry Golubovsky [EMAIL PROTECTED]: Hi, I finally got the Yhc Web Service (web-based front end to the compiler) running in public testing mode. There hasn't been any documentation written, and Haddock stuff not brought in order, but if anyone wants to just get a taste of it, please open this hpaste entry: http://hpaste.org/6094 and follow the instructions. In 10 steps, you'll get Haskell to work in your web browser* ;) No need to install anything. Feel free to edit the source code, and even deliberately make errors to see how error log looks. At the moment, I do not run automatic cleanup of failed compilations. This is one of my old tests, not showing any GUI interaction. However, both documents browser and new entry form were written in Haskell which gives some idea about what can be done. Sources of these forms are in the Yhc repo. Thanks. --- * Likely, your results will be better with Firefox than with MSIE. But MSIE should work as well. -- Dimitry Golubovsky Anywhere on the Web ___ Yhc mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/yhc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Functional programmer's intuition for adjunctions?
Well, I think it's really cool to be sitting in cafe exchanging some сute facts from category theory we happen to know. Girls would definitely like it. On 5 Mar 2008, at 03:33, Derek Elkins wrote: On Tue, 2008-03-04 at 19:01 +, Dominic Steinitz wrote: Well, we have at least one very useful example of adjunction. It's called curry. See, if X is some arbitrary type, you can define This adjunction is the one that makes a category cartesian closed. and the monad for it gives rise to the state monad. And the other adjunction relating to exponentials and symmetry gives rise to the continuation monad. ___ 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] Functional programmer's intuition for adjunctions?
On Tue, 2008-03-04 at 18:30 +, Edsko de Vries wrote: On Tue, Mar 04, 2008 at 11:58:38AM -0600, Derek Elkins wrote: On Tue, 2008-03-04 at 17:16 +, Edsko de Vries wrote: Hi, Is there an intuition that can be used to explain adjunctions to functional programmers, even if the match isn't necessary 100% perfect (like natural transformations and polymorphic functions?). Well when you pretend Hask is Set, many things can be discussed fairly directly. F is left adjoint to U, F -| U, if Hom(FA,B) is naturally isomorphic to Hom(A,UB), natural in A and B. A natural transformation over Set is just a polymorphic function. So we have an adjunction if we have two functions: phi :: (F a - b) - (a - U b) and phiInv :: (a - U b) - (F a - b) such that phi . phiInv = id and phiInv . phi = id and F and U are instances of Functor. The unit and counit respectively is then just phi id and phiInv id. Sure, but that doesn't really explain what an adjunction *is*. For me, it helps to think of a natural transformation as a polymorphic function: it gives me an intuition about what a natural transformation is. Specializing the definition of an adjunction for Hask (or Set) helps understanding the *definitions*, but not the *intention*, if that makes any sense.. I explicitly mentioned this at the end of my first email: Of course, this is a concrete example using basic ideas of programming and not some intuitive analogy. I feel comfortable working with adjunctions, but I don't have some general analogy that I use. I'm suggesting that trying to find such an analogy may be more trouble than it is worth. The best analogy I've heard is to relate the problem of finding an adjunction to optimization problems. Personally, I find representability to be simpler, more useful, and easier to get an intuition about. Adjunction is then a particular case of parameterized representability. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Exporting Haskell Libraries to C Programmers
Don Stewart dons at galois.com writes: joseph.bruce: Hi, I have a Haskell library that I want to make available via FFI to C programmers on my project team. I read this thread (http://thread.gmane.org/gmane.comp.lang.haskell.cafe/21447) which had some interesting ideas, but they seemed unresolved. Or maybe it answers my question but I don't understand it. Is there a way I can package (ghc-)compiled Haskell code into a statically-linked library and not force the C programmers to include headers and libraries that they have no knowledge of and undefine a seemingly endless list of preprocessor symbols (run ghc with the verbose flag and look at the calls to gcc)? Can this process be automated? Yes, check the FFI documentation for the main story. In short, build the Haskell code with cabal, with your foreign export Haskell functions in the cbits. That bundle can then be linked against C code. You do need to link your app against libHSrts.a and libHSbase.a (and other libs you use), but assuming you foreign export, the code to call will look just like normal C stuff. Thanks Don. I finally got back to this. I hadn't looked at CABAL before. It's a very useful tool and met all my library-forming needs. That's only half my problem though. I'm trying to make the use of this Haskell code as transparent as possible to the C programmers on the team. Telling them about the Haskell base libraries dependency or distributing those libraries with my code is not too bad, but the list of -u flags that the linker needs is brutal. Is there a way to avoid it, or embed it in the package? Ex (using ghc-6.8.2 -v): ... gcc -v -o primes Primes.o ./Primes_stub.o hs_primes_wrapper.o cprimes.c -Bc:\ghc\ghc-6.8.2\gcc-lib/ -DDONT_WANT_WIN32_DLL_SUPPORT -Lc:/ghc/ghc-6.8.2/lib\base-3.0.1.0 -Lc:/ghc/ghc-6.8.2 -Lc:/ghc/ghc-6.8.2/gcc-lib -lHSbase-3.0.1.0 -lwsock32 -lmsvcrt -lkernel32 -luser32 -lshell32 -lHSrts -lm -lgmp -lwsock32 -u _base_GHCziBase_Izh_static_info -u _base_GHCziBase_Czh_static_info -u _base_GHCziFloat_Fzh_static_info -u _base_GHCziFloat_Dzh_static_info -u _base_GHCziPtr_Ptr_static_info -u _base_GHCziWord_Wzh_static_info -u _base_GHCziInt_I8zh_static_info -u _base_GHCziInt_I16zh_static_info -u _base_GHCziInt_I32zh_static_info -u _base_GHCziInt_I64zh_static_info -u _base_GHCziWord_W8zh_static_info -u _base_GHCziWord_W16zh_static_info -u _base_GHCziWord_W32zh_static_info -u _base_GHCziWord_W64zh_static_info -u _base_GHCziStable_StablePtr_static_info -u _base_GHCziBase_Izh_con_info -u _base_GHCziBase_Czh_con_info -u _base_GHCziFloat_Fzh_con_info -u _base_GHCziFloat_Dzh_con_info -u _base_GHCziPtr_Ptr_con_info -u _base_GHCziPtr_FunPtr_con_info -u _base_GHCziStable_StablePtr_con_info -u _base_GHCziBase_False_closure -u _base_GHCziBase_True_closure -u _base_GHCziPack_unpackCString_closure -u _base_GHCziIOBase_stackOverflow_closure -u _base_GHCziIOBase_heapOverflow_closure -u _base_GHCziIOBase_NonTermination_closure -u _base_GHCziIOBase_BlockedOnDeadMVar_closure -u _base_GHCziIOBase_BlockedIndefinitely_closure -u _base_GHCziIOBase_Deadlock_closure -u _base_GHCziIOBase_NestedAtomically_closure -u _base_GHCziWeak_runFinalizzerBatch_closure -u _base_GHCziConc_ensureIOManagerIsRunning_closure ... This particular example is a build on a windows system and makes use of the .o's directly and not the .a I create, but those are of no consequence as this is ultimately a linking issue, not a compilation issue. I don't know what these -u's are for, but I know that if I take them out, the linker fails. They do change from one system to another (this list fails with the linker on RHEL 5). But right now my solution for the C programmers is a make file with $haskell_undefine_flags = that mess up there, and I'd prefer something more elegant and less system dependent. I am willing to accept that there is no good way around it, but perhaps someone has dealt with this issue before. Any help? Thanks. Joe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: problem in using wash
Thanks for the information. Now I could find mistake in what I was importing. 'ghc-pkg describe WashNGo' told me correct exported module names. On 05/03/2008, Ferenc Wagner [EMAIL PROTECTED] wrote: Vikrant [EMAIL PROTECTED] writes: I was trying to use wash to learn it. I am using ubuntu and I have ghc6.6.1 installed on my system. I have also installed the package libghc6-wash-dev but in my code when i write import WASH.CGI it gives me following error firstCGI.hs:5:7: Could not find module `WASH.CGI': locations searched: WASH/CGI.hs WASH/CGI.lhs Failed, modules loaded: none. can somebody help me in this? Check with 'ghc-pkg list' if the package is present, then use 'ghc-pkg describe WashNGo' to get the exported module names. Also don't forget to use --make when compiling (or explicit package name). -- Regards, Feri. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
