Re: [Haskell-cafe] Panic loading network on windows (GHC 7.6.1)
On Fri, 05 Oct 2012 17:31:49 +0200, JP Moresmau jpmores...@gmail.com wrote: Hello, I've installed Cabal and cabal-install 1.16 (which required network) on a new GHC 7.6.1 install and everything went well, except now when building a package requiring network I get: Loading package network-2.4.0.1 ... ghc.exe: Unknown PEi386 section name `.idata $4' (while processing: c:/ghc/ghc-7.6.1/mingw/lib\libws2_32.a) ghc.exe: panic! (the 'impossible' happened) (GHC version 7.6.1 for i386-unknown-mingw32): loadArchive c:/ghc/ghc-7.6.1/mingw/lib\\libws2_32.a: failed It's a GHC bug and will be solved in GHC 7.6.2, according to: http://hackage.haskell.org/trac/ghc/ticket/7103 Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] referential transparency? (for fixity of local operators)
wren ng thornton wren at freegeek.org writes: As for whether the default should be infix 9 instead of infixl 9 ... that was exactly the point of my message. - J. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cabal dependencies
Hello, I'm trying to understand Cabal dependencies. Why does the following situation happen? # cabal install xmobar --dry-run Resolving dependencies... In order, the following would be installed: parsec-3.1.3 (reinstall) changes: mtl-2.1.1 - 2.0.1.0 xmobar-0.15 (new package) Warning: The following packages are likely to be broken by the reinstalls: texmath-0.6.1.1 regex-tdfa-1.1.8 Unixutils-1.50 network-2.4.0.1 HTTP-4000.2.5 network-2.3.0.14 sendfile-0.7.6 happstack-server-7.0.7 happstack-hsp-7.1.0 happstack-7.0.0 hslogger-1.1.5 citeproc-hs-0.3.4 acid-state-0.6.4 HTTP-4000.2.3 ltk-0.12.1.0 json-0.5 highlighting-kate-0.5.1 Use --force-reinstalls if you want to install anyway. Best regards, José -- José António Branquinho de Oliveira Lopes Instituto Superior Técnico Technical University of Lisbon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
On Sat, 2012-10-06 at 17:02 +0200, José Lopes wrote: Hello, Hello I'm trying to understand Cabal dependencies. Why does the following situation happen? xmobar-0.15 depends on mtl-2.0.* and needs parsec All packages that will be broken, depends on parsec. But parsec is compiled with mtl-2.1.1 To install xmobar, cabal needs to reinstall parsec with mtl-2.0.1.0 Thanks, Yuras # cabal install xmobar --dry-run Resolving dependencies... In order, the following would be installed: parsec-3.1.3 (reinstall) changes: mtl-2.1.1 - 2.0.1.0 xmobar-0.15 (new package) Warning: The following packages are likely to be broken by the reinstalls: Best regards, José ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] referential transparency? (for fixity of local operators)
On 12-10-06 05:18 AM, Johannes Waldmann wrote: wren ng thornton wren at freegeek.org writes: As for whether the default should be infix 9 instead of infixl 9 ... that was exactly the point of my message. - J. Perhaps, half of the people want infixl, another half of the people want infixr, and so at the end the middle ground of neither l nor r is taken. Perhaps, political decision is about saying no to both the left and the right? :) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Benchmarks for graph algorithms
Hi cafe, Where do Haskell and DPH stand in comparison to C/OpenMP w.r.t. graph algorithms? Are benchmarks for graph algorithms available for Haskell like the ones we find at http://www.graphanalysis.org/benchmark/? - Damodar ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Thanks, José On 06-10-2012 17:17, Yuras Shumovich wrote: On Sat, 2012-10-06 at 17:02 +0200, José Lopes wrote: Hello, Hello I'm trying to understand Cabal dependencies. Why does the following situation happen? xmobar-0.15 depends on mtl-2.0.* and needs parsec All packages that will be broken, depends on parsec. But parsec is compiled with mtl-2.1.1 To install xmobar, cabal needs to reinstall parsec with mtl-2.0.1.0 Thanks, Yuras # cabal install xmobar --dry-run Resolving dependencies... In order, the following would be installed: parsec-3.1.3 (reinstall) changes: mtl-2.1.1 - 2.0.1.0 xmobar-0.15 (new package) Warning: The following packages are likely to be broken by the reinstalls: Best regards, José -- José António Branquinho de Oliveira Lopes Instituto Superior Técnico Technical University of Lisbon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
On 6 October 2012 17:25, José Lopes jose.lo...@ist.utl.pt wrote: OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Possibly, yes, but cabal doesn't know that. It has to make the conservative assumption that you might use them together and so they'd better be the same type. If cabal knew for sure that parsec did not expose types from mtl, then it'd be fine for it to use parsec built against a different version of mtl, because there would be no way to end up trying to equate types from two different package instances. This is the idea behind private or encapsulated dependencies: we would declare in .cabal files that our use of some dependency does not leak out. But to be clear: this feature has not yet been implemented. But actually in this case I think parsec does expose the fact that it uses types from mtl. So it actually would not help here. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
On Sat, 2012-10-06 at 18:25 +0200, José Lopes wrote: OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Usually it leads to strange compilation errors. E.g. Package A: data AA = AA String func0 :: Int - AA func0 n = AA $ replicate n A func1 :: AA - Int func1 (AA str) = length str Package B: import A func2 :: AA - Int func2 aa = func1 + 1 Package C: import A import B func3 :: Int - Int func3 n = func2 $ func0 n If C and B are compiled with different versions of C, then func3 will not compile. Compiler will say that AA returned by func0 doesn't match AA expected by func2 More real examples: http://stackoverflow.com/questions/11068272/acid-state-monadstate-instance-for-update http://stackoverflow.com/questions/12576817/couldnt-match-expected-type-with-actual-type-error-when-using-codec-bmp/12577025#12577025 Thanks, José ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Am I the only one having problems with RWH?
I began learning Haskell 9 months ago. I still consider myself a beginner, but I'm progressing towards more advanced concepts. I read scientific papers (simpler ones) and books about Haskell and functional programming. Right now I'm reading Pearls of Functional Algorithm Design, Introduction to Functional Programming, Implementation of Functional Programming Languages and Real World Haskell. RWH is causing me a lot of trouble though. This leads me to frustration because book covers rather basic material. I just spent another 1,5 hour reading chapter 10 again and trying to understand how presented parsing functions work. Even if I am barely able to grasp what is going on I feel that I wouldn't know how to write such code by myself. Am I the only one having such problems with RWH? Jan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Am I the only one having problems with RWH?
I'm not totally sure if you're having problems with RWH, or think it's too easy, but here are my thoughts on both: Both RWH and LYAH (http://learnyouahaskell.com/) are intended for beginners/people who just want to get started, and RWH tends to be regarded as the hardest to understand (read LYAH then RWH.) (RWH is also specifically aimed at demonstrating how to solve practical problems, not hard/academical ones.) I too agree that LYAH is the easier one, and it is slightly more focused on the theory and concepts of Haskell, so I would definitely recommend checking that out. I found that the topics and chapters of the two books mix nicely--you don't get the feeling that you're just reading the same book twice. For other Haskell-related writings, Simon Marlow is currently writing a book based on his Parallel and Concurrent Programming in Haskell tutorial (http://community.haskell.org/~simonmar/par-tutorial.pdf) for O'Reilly at the moment. In the meantime, I've found the Simons' papers to be interesting reading: http://research.microsoft.com/en-us/people/simonpj/ http://research.microsoft.com/en-us/people/simonmar/ The level of the papers range from LYAH-style material to the more abstract/advanced a la Philip Wadler's Theorems For Free (http://ttic.uchicago.edu/~dreyer/course/papers/wadler.pdf) Most of Philip Wadler's papers are also very interesting: http://homepages.inf.ed.ac.uk/wadler/ So, you're probably at a level where you'll want to start looking for interesting academical papers on Haskell/FP and theory, then re-visit RWH once in a while. I found the papers on STM, Cloud Haskell, and Parallel Haskell, to be the most interesting, easy to understand, and practically useful. On Sat, Oct 6, 2012 at 1:41 PM, Janek S. fremenz...@poczta.onet.pl wrote: I began learning Haskell 9 months ago. I still consider myself a beginner, but I'm progressing towards more advanced concepts. I read scientific papers (simpler ones) and books about Haskell and functional programming. Right now I'm reading Pearls of Functional Algorithm Design, Introduction to Functional Programming, Implementation of Functional Programming Languages and Real World Haskell. RWH is causing me a lot of trouble though. This leads me to frustration because book covers rather basic material. I just spent another 1,5 hour reading chapter 10 again and trying to understand how presented parsing functions work. Even if I am barely able to grasp what is going on I feel that I wouldn't know how to write such code by myself. Am I the only one having such problems with RWH? Jan ___ 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] Am I the only one having problems with RWH?
I also had problems when I began reading RHW, early in my career as a Haskell beginner. The functional pearl on monadic parsers by Hutton and Meijer was a great help in understanding the thinking behind Parsec. While reading it, I had some difficulty understanding why certain functions should ever terminate, but once I got past that, it made chapter 10 of RWH much easier to understand. Also, the functional pearl on applicative functors by Conor McBride and a second author (can't recall his name) blew the door open on the subject, for me. On Sat, Oct 6, 2012 at 1:03 PM, Patrick Mylund Nielsen hask...@patrickmylund.com wrote: I'm not totally sure if you're having problems with RWH, or think it's too easy, but here are my thoughts on both: Both RWH and LYAH (http://learnyouahaskell.com/) are intended for beginners/people who just want to get started, and RWH tends to be regarded as the hardest to understand (read LYAH then RWH.) (RWH is also specifically aimed at demonstrating how to solve practical problems, not hard/academical ones.) I too agree that LYAH is the easier one, and it is slightly more focused on the theory and concepts of Haskell, so I would definitely recommend checking that out. I found that the topics and chapters of the two books mix nicely--you don't get the feeling that you're just reading the same book twice. For other Haskell-related writings, Simon Marlow is currently writing a book based on his Parallel and Concurrent Programming in Haskell tutorial (http://community.haskell.org/~simonmar/par-tutorial.pdf) for O'Reilly at the moment. In the meantime, I've found the Simons' papers to be interesting reading: http://research.microsoft.com/en-us/people/simonpj/ http://research.microsoft.com/en-us/people/simonmar/ The level of the papers range from LYAH-style material to the more abstract/advanced a la Philip Wadler's Theorems For Free (http://ttic.uchicago.edu/~dreyer/course/papers/wadler.pdf) Most of Philip Wadler's papers are also very interesting: http://homepages.inf.ed.ac.uk/wadler/ So, you're probably at a level where you'll want to start looking for interesting academical papers on Haskell/FP and theory, then re-visit RWH once in a while. I found the papers on STM, Cloud Haskell, and Parallel Haskell, to be the most interesting, easy to understand, and practically useful. On Sat, Oct 6, 2012 at 1:41 PM, Janek S. fremenz...@poczta.onet.pl wrote: I began learning Haskell 9 months ago. I still consider myself a beginner, but I'm progressing towards more advanced concepts. I read scientific papers (simpler ones) and books about Haskell and functional programming. Right now I'm reading Pearls of Functional Algorithm Design, Introduction to Functional Programming, Implementation of Functional Programming Languages and Real World Haskell. RWH is causing me a lot of trouble though. This leads me to frustration because book covers rather basic material. I just spent another 1,5 hour reading chapter 10 again and trying to understand how presented parsing functions work. Even if I am barely able to grasp what is going on I feel that I wouldn't know how to write such code by myself. Am I the only one having such problems with RWH? Jan ___ 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 mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Am I the only one having problems with RWH?
Dnia sobota, 6 października 2012, Mark Thom napisał: Also, the functional pearl on applicative functors by Conor McBride and a second author (can't recall his name) blew the door open on the subject, for me. Good to hear, it's in front of me on the desk and I'm planning to finish that pearl tomorrow (BTW. Ross Paterson is the second author). I'm not totally sure if you're having problems with RWH, or think it's too easy, but here are my thoughts on both: I consider RWH to be a bit too hard for me. I too agree that LYAH is the easier one, and it is slightly more focused on the theory and concepts of Haskell, so I would definitely recommend checking that out. I already read LYAH. For other Haskell-related writings, Simon Marlow is currently writing a book based on his Parallel and Concurrent Programming in Haskell tutorial (http://community.haskell.org/~simonmar/par-tutorial.pdf) for O'Reilly at the moment. In the meantime, I've found the Simons' papers to be interesting reading: Yes, I know about the upcomming book and I'm awaiting it. Right now I'm digging through REPA papers, but Marlow's tutorial is next on my list of things to read. So, you're probably at a level where you'll want to start looking for interesting academical papers on Haskell/FP and theory, then re-visit RWH once in a while Well, I figured out that before I go into more academic stuff I should have more knowledge about the basics, which I thought would be covered by RWH. Hence my frustration from not understanding a book that's supposed to introduce people to Haskell. I guess I'll start with reading some papers on parallelism and go back to RWH when I have more experience. Jan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Panic loading network on windows (GHC 7.6.1)
Just to explain what's going on. It looks like you are compiling a module that uses template haskell, which in turn relies on GHCi bits. In particular, GHCi has a custom linker for loading compiled code. This linker is very fragile and tends to break whenever the platform GCC/linker changes. Similar issues happen a lot on OS X, because Apple tends to change their library formats on most major releases. The only workaround I can think of is to avoid using GHCi or Template Haskell, but I understand that's usually very tricky (especially if one of the dependencies uses TH). On 6 October 2012 09:57, Henk-Jan van Tuyl hjgt...@chello.nl wrote: On Fri, 05 Oct 2012 17:31:49 +0200, JP Moresmau jpmores...@gmail.com wrote: Hello, I've installed Cabal and cabal-install 1.16 (which required network) on a new GHC 7.6.1 install and everything went well, except now when building a package requiring network I get: Loading package network-2.4.0.1 ... ghc.exe: Unknown PEi386 section name `.idata $4' (while processing: c:/ghc/ghc-7.6.1/mingw/lib\libws2_32.a) ghc.exe: panic! (the 'impossible' happened) (GHC version 7.6.1 for i386-unknown-mingw32): loadArchive c:/ghc/ghc-7.6.1/mingw/lib\\libws2_32.a: failed It's a GHC bug and will be solved in GHC 7.6.2, according to: http://hackage.haskell.org/trac/ghc/ticket/7103 Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] object file cannot be loaded.
Does `ghc-pkg check` report any issues? On 6 October 2012 15:24, Magicloud Magiclouds magicloud.magiclo...@gmail.com wrote: Hi, I am installing postgres hackage (cannot remember the exact name right now). When it compiling the template haskell part I got the following error message. I tried to clear all user space hackages. Not helping. Loading package text-0.11.2.3 ... linking ... ghc: /home/magicloud/.cabal/lib/text-0.11.2.3/ghc-7.6.1/HStext-0.11.2.3.o: unknown symbol `bytestringzm0zi10zi0zi1_DataziByteStringziInternal_PS_con_info' ghc: unable to load package `text-0.11.2.3' -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
OK. Got it! Do you have any suggestions to install xmobar in this particular case? Thanks, José On 06-10-2012 19:08, Yuras Shumovich wrote: On Sat, 2012-10-06 at 18:25 +0200, José Lopes wrote: OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Usually it leads to strange compilation errors. E.g. Package A: data AA = AA String func0 :: Int - AA func0 n = AA $ replicate n A func1 :: AA - Int func1 (AA str) = length str Package B: import A func2 :: AA - Int func2 aa = func1 + 1 Package C: import A import B func3 :: Int - Int func3 n = func2 $ func0 n If C and B are compiled with different versions of C, then func3 will not compile. Compiler will say that AA returned by func0 doesn't match AA expected by func2 More real examples: http://stackoverflow.com/questions/11068272/acid-state-monadstate-instance-for-update http://stackoverflow.com/questions/12576817/couldnt-match-expected-type-with-actual-type-error-when-using-codec-bmp/12577025#12577025 Thanks, José -- José António Branquinho de Oliveira Lopes Instituto Superior Técnico Technical University of Lisbon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Am I the only one having problems with RWH?
I found I had to keep switching between RWH and other books for these concepts to sink in. A really good resource that I don't see mentioned too often is the Haskell wikibook: http://en.wikibooks.org/wiki/Haskell I don't remember it covering parsec specifically but if you get grounded in all the concepts there, the RWH chapters on parsec will make more sense. It also helped me to take breaks from RWH and re-read chapters later. Also if you find yourself getting discouraged, I really like Brent Yorgey's article on the monad tutorial fallacy: http://byorgey.wordpress.com/2009/01/12/abstraction-intuition-and-the-monad-tutorial-fallacy/ It uses monads as an example but describes the process of learning difficult concepts. On Sat, Oct 6, 2012 at 12:54 PM, Janek S. fremenz...@poczta.onet.pl wrote: Dnia sobota, 6 października 2012, Mark Thom napisał: Also, the functional pearl on applicative functors by Conor McBride and a second author (can't recall his name) blew the door open on the subject, for me. Good to hear, it's in front of me on the desk and I'm planning to finish that pearl tomorrow (BTW. Ross Paterson is the second author). I'm not totally sure if you're having problems with RWH, or think it's too easy, but here are my thoughts on both: I consider RWH to be a bit too hard for me. I too agree that LYAH is the easier one, and it is slightly more focused on the theory and concepts of Haskell, so I would definitely recommend checking that out. I already read LYAH. For other Haskell-related writings, Simon Marlow is currently writing a book based on his Parallel and Concurrent Programming in Haskell tutorial (http://community.haskell.org/~simonmar/par-tutorial.pdf) for O'Reilly at the moment. In the meantime, I've found the Simons' papers to be interesting reading: Yes, I know about the upcomming book and I'm awaiting it. Right now I'm digging through REPA papers, but Marlow's tutorial is next on my list of things to read. So, you're probably at a level where you'll want to start looking for interesting academical papers on Haskell/FP and theory, then re-visit RWH once in a while Well, I figured out that before I go into more academic stuff I should have more knowledge about the basics, which I thought would be covered by RWH. Hence my frustration from not understanding a book that's supposed to introduce people to Haskell. I guess I'll start with reading some papers on parallelism and go back to RWH when I have more experience. Jan ___ 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 dependencies
On Sat, 2012-10-06 at 22:40 +0200, José Lopes wrote: OK. Got it! Do you have any suggestions to install xmobar in this particular case? In case of executables I usually rm -rf ~/.ghc, cabal install, and rm -rf ~/.ghc again. Executables are still here (in ~/.cabal/bin), but all libraries are lost. Warning: it may break your development environment, so make sure you know what you are doing. Better solution could be sandbox tools like cabal-dev. They alloy you to setup development environment per project. Thanks, José On 06-10-2012 19:08, Yuras Shumovich wrote: On Sat, 2012-10-06 at 18:25 +0200, José Lopes wrote: OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Usually it leads to strange compilation errors. E.g. Package A: data AA = AA String func0 :: Int - AA func0 n = AA $ replicate n A func1 :: AA - Int func1 (AA str) = length str Package B: import A func2 :: AA - Int func2 aa = func1 + 1 Package C: import A import B func3 :: Int - Int func3 n = func2 $ func0 n If C and B are compiled with different versions of C, then func3 will not compile. Compiler will say that AA returned by func0 doesn't match AA expected by func2 More real examples: http://stackoverflow.com/questions/11068272/acid-state-monadstate-instance-for-update http://stackoverflow.com/questions/12576817/couldnt-match-expected-type-with-actual-type-error-when-using-codec-bmp/12577025#12577025 Thanks, José ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
Thanks! On 06-10-2012 23:07, Yuras Shumovich wrote: On Sat, 2012-10-06 at 22:40 +0200, José Lopes wrote: OK. Got it! Do you have any suggestions to install xmobar in this particular case? In case of executables I usually rm -rf ~/.ghc, cabal install, and rm -rf ~/.ghc again. Executables are still here (in ~/.cabal/bin), but all libraries are lost. Warning: it may break your development environment, so make sure you know what you are doing. Better solution could be sandbox tools like cabal-dev. They alloy you to setup development environment per project. Thanks, José On 06-10-2012 19:08, Yuras Shumovich wrote: On Sat, 2012-10-06 at 18:25 +0200, José Lopes wrote: OK. But, wouldn't it be possible for xmobar to use mtl-2.0.1.0 and for parsec to use mtl-2.1.1, while xmobar would use this parsec version? In this case, I am assuming that mtl-2.0.1.0 and mtl-2.1.1 are considered two different libraries. Usually it leads to strange compilation errors. E.g. Package A: data AA = AA String func0 :: Int - AA func0 n = AA $ replicate n A func1 :: AA - Int func1 (AA str) = length str Package B: import A func2 :: AA - Int func2 aa = func1 + 1 Package C: import A import B func3 :: Int - Int func3 n = func2 $ func0 n If C and B are compiled with different versions of C, then func3 will not compile. Compiler will say that AA returned by func0 doesn't match AA expected by func2 More real examples: http://stackoverflow.com/questions/11068272/acid-state-monadstate-instance-for-update http://stackoverflow.com/questions/12576817/couldnt-match-expected-type-with-actual-type-error-when-using-codec-bmp/12577025#12577025 Thanks, José -- José António Branquinho de Oliveira Lopes Instituto Superior Técnico Technical University of Lisbon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal dependencies
Do you have any suggestions to install xmobar in this particular case? In case of executables I usually rm -rf ~/.ghc, cabal install, and rm -rf ~/.ghc again. Executables are still here (in ~/.cabal/bin), but all libraries are lost. Warning: it may break your development environment, so make sure you know what you are doing. Better solution could be sandbox tools like cabal-dev. They alloy you to setup development environment per project. In this particular case, removing all libraries is total overkill. That should be reserved for situations where the package DB is already broken, but afaiu, this has not happened here yet. I'm quite convinced xmobar-0.15 actually works with the more recent mtl. So you can try: $ cabal unpack xmobar $ cd xmobar-0.15 edit the xmobar.cabal file and remove the upper bound from mtl $ cabal install Cheers, Andres ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] object file cannot be loaded.
There is none On Sun, Oct 7, 2012 at 4:27 AM, Thomas Schilling nomin...@googlemail.com wrote: Does `ghc-pkg check` report any issues? On 6 October 2012 15:24, Magicloud Magiclouds magicloud.magiclo...@gmail.com wrote: Hi, I am installing postgres hackage (cannot remember the exact name right now). When it compiling the template haskell part I got the following error message. I tried to clear all user space hackages. Not helping. Loading package text-0.11.2.3 ... linking ... ghc: /home/magicloud/.cabal/lib/text-0.11.2.3/ghc-7.6.1/HStext-0.11.2.3.o: unknown symbol `bytestringzm0zi10zi0zi1_DataziByteStringziInternal_PS_con_info' ghc: unable to load package `text-0.11.2.3' -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
