[Haskell-cafe] Cabal + yi + alex problem.
I cannot seem to be able to install yi via cabal install. The error I get is as follows. I suspect alex is not installed in the correct place. ; sudo cabal install yi Resolving dependencies... Downloading yi-0.4.3... Configuring yi-0.4.3... cabal: alex version =2.0.1 3 is required but it could not be found. cabal: Error: some packages failed to install: yi-0.4.3 failed during the configure step. The exception was: exit: ExitFailure 1 ; sudo cabal install alex Resolving dependencies... Downloading alex-2.2... [1 of 1] Compiling Main ( Setup.lhs, dist/setup/Main.o ) Linking dist/setup/setup ... Warning: defaultUserHooks in Setup script is deprecated. Configuring alex-2.2... Warning: No 'build-type' specified. If you do not need a custom Setup.hs or ./configure script then use 'build-type: Simple'. Preprocessing executables for alex-2.2... Building alex-2.2... [...] Linking dist/build/alex/alex ... Installing: /home/yann/.cabal/bin ; sudo cabal install yi Resolving dependencies... 'yi-0.4.3' is cached. Configuring yi-0.4.3... cabal: alex version =2.0.1 3 is required but it could not be found. cabal: Error: some packages failed to install: yi-0.4.3 failed during the configure step. The exception was: exit: ExitFailure 1 -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpKLe5vZlfvS.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal + yi + alex problem.
Quoth Austin Seipp on Wed, Jul 30, 2008 at 03:45:49 -0500 Excerpts from Yann Golanski's message of Wed Jul 30 02:34:05 -0500 2008: I cannot seem to be able to install yi via cabal install. The error I get is as follows. I suspect alex is not installed in the correct place. ... Hi, cabal-install will put installed binaries in $HOME/.cabal/bin by default as far as I can tell, you should move the binary somewhere in your $PATH if you want cabal-install to pick it up for installing yi. Well, that indeed sorted that one. But still no luck: ; sudo cabal install yi Resolving dependencies... 'yi-0.4.3' is cached. Configuring yi-0.4.3... Preprocessing library yi-0.4.3... Preprocessing executables for yi-0.4.3... Building yi-0.4.3... Yi/UI/Vty.hs:42:7: Could not find module `Graphics.Vty': Use -v to see a list of the files searched for. cabal: Error: some packages failed to install: yi-0.4.3 failed during the building phase. The exception was: exit: ExitFailure 1 -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpPeH72jqpSQ.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal + yi + alex problem.
Quoth Nicolas Pouillard on Wed, Jul 30, 2008 at 11:06:43 +0200 Excerpts from Yann Golanski's message of Wed Jul 30 10:59:35 +0200 2008: ; sudo cabal install yi Resolving dependencies... 'yi-0.4.3' is cached. Configuring yi-0.4.3... Preprocessing library yi-0.4.3... Preprocessing executables for yi-0.4.3... Building yi-0.4.3... Yi/UI/Vty.hs:42:7: Could not find module `Graphics.Vty': Use -v to see a list of the files searched for. cabal: Error: some packages failed to install: yi-0.4.3 failed during the building phase. The exception was: exit: ExitFailure 1 Can you try the vty flag: $ sudo cabal install yi -fvty Sadly, I get the same error as before. What debugging output would you need? -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpIbgGSwobZH.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Rotating backdrop (aka learning Haskell)
First version is available at: http://www.kierun.org/backdropper-1.0.tbz2 It is minimal but does the trick of randomly rotating backgrounds. Features to add are only rotate during work hours, making sure that all images are shown within a day and a nice GUI. Criticism welcome. -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgp1DQpdVc35O.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Images and GUIs in Haskell
Quoth Achim Schneider on Sun, Jun 01, 2008 at 04:09:10 +0200 I would go for GL(U(T)), as it's as good for 2d primitives as SDL will ever be, has excellent cross-platform support and allows you to go 3d if you want to. There's also some very decent event handling. You can use R as well. http://www.r-project.org/ -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpUxe2kMb6IX.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What's NaN?
Quoth PR Stanley on Wed, May 28, 2008 at 08:04:44 +0100 Hello Why does sqrt (-16) return NaN? What is NaN? NaN stands for Not a Number. See the complex library for how to have complex numbers. -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpzsKbaJOQdu.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Rotating backdrop (aka learning Haskell)
Quoth Derek Elkins on Tue, May 20, 2008 at 11:45:57 -0500 On Tue, 2008-05-20 at 10:55 +0200, Ketil Malde wrote: Yann Golanski [EMAIL PROTECTED] writes: 1- Get a list out of a file: I managed to do that using the following: parseImageFile :: FilePath - IO [String] parseImageFile file = do inpStr - readFile file return $ filter (/=) (breaks (=='\n') inpStr) Nice, simple and I understand what it is doing. Can be improved: breaks (=='\n') == lines -- easier to read, no? filter (/=) == filter (not . null) -- more polymorphic, not important here do x - expr1== expr1 = return . expr2 return $ expr2 x -- i.e. readFile f = return . filter (not.null) . lines do x - expr1; return $ expr2 x == expr1 = return . expr2 == liftM expr2 expr1 -- or fmap (a.k.a. $) if you like So, liftM (filter (not . null) . lines) readFile alternatively, filter (not . null) . lines $ readFile I'm sorry, this is a little beyond me. Could you elaborate a little more on what this actually does? -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpRApk90uNyx.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Rotating backdrop (aka learning Haskell)
To help me learn Haskell, I decided on a simple (AH!) problem: given a list of images, display a random one as my desktop backdrop. After some time, change the image. Simple? What I actually want to do is a little more specific: Read a list of images (one per line) from a file. Given that a working day is about 8 hours, I want to see all the images during the day. So, the time between changes should be (nbr_of_images) / (8 * 60 * 60) seconds. Of course, if the file changes (I add or remove any number of images) this need to change and be recalculated. Clearly, I want some interaction with a pseudo-random number generator. Because this is a learning exercise, I want to have a pretty GUI for this. Three buttons: Exit (which quits the application), Reset (re-reads the file whether it changed or not) and Next (display the next image). Then I want a counter and a progress bar telling me when the next change will occur. 1- Get a list out of a file: I managed to do that using the following: parseImageFile :: FilePath - IO [String] parseImageFile file = do inpStr - readFile file return $ filter (/=) (breaks (=='\n') inpStr) Nice, simple and I understand what it is doing. 2- Get a random element from a list and remove it: Okay, this I understand less well. I looked at the solutions of problems 23 and 20 in http://www.haskell.org/haskellwiki/99_questions so there is a skeleton there. However, my list is IO [String] Hum, monads. Any pointers as to how to do that? 3- Wait and do something later How, I have no idea how to do that! Help? 4- I guess that progress bars and updating text will be somewhere in the GUI (I chose wxHaskell)... Again, no idea where. 5- How do you call an external program in Haskell? Either xv or Esetroot will do the job of displaying the image. Is there a Haskell native way to do that? Once this is done and I have commented to the code, I will be happy to put it onto the wiki as a teaching aid. Thanks. -- [EMAIL PROTECTED] -= H+ =- www.kierun.org PGP: 009D 7287 C4A7 FD4F 1680 06E4 F751 7006 9DE2 6318 pgpKXqHHbxvtL.pgp Description: PGP signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
