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[Beginner's Question] How to read filenames from a DirStream
by Albert Lee 09 Apr '07

09 Apr '07

Newbie's question: I want to ls the filenames of a directory. The program in C is something like: #include <direnet.h> int main(){ DIR *dp; struct dirent *dirp; dp = opendir("/"); while((dirp = readdir(dp)) != NULL) printf("%s\n", dirp->d_name); closedir(dp); } and I write that in haskell: ----- import System.Posix import System.IO main = do dp <- openDirStream "/" df <- readDirStream dp putStrLn df closeDirStream dp ------ It can print the first entry of the dir, but how can we list it all like the C prog? map ? list comperhension?

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runInteractiveCommand
by Sergey Perminov 09 Apr '07

09 Apr '07

I wished to get output of unix commands in haskell code. So i wrote: ---------------------------------------------------------------------------------- import System.IO import System.Process eval :: String -> IO String eval s = do (_,hOutput,_,hProcess) <- runInteractiveCommand s sOutput <- hGetContents hOutput waitForProcess hProcess return sOutput ---------------------------------------------------------------------------------- 'eval' works well if output of evaluated command is less than 64Kb. If not - 'eval' never ends. What may cause this problem? Is it possible to use 'runInteractiveCommand' when command's output size is longer than 64Kb? -- Best regards, Sergey Perminov

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Re: [Haskell-cafe] runInteractiveCommand
by Dave Feustel 09 Apr '07

09 Apr '07

I tried the code below with both ghc 6.2.2 and hugs march 2005. ghc: "The last statement in a 'do' construct must be an expression" Hugs ERROR "interactive.hs" - Can't find imported module "System.Process" . >---------------------------------------------------------------------------------- >import System.IO >import System.Process > >eval :: String -> IO String >eval s = do (_,hOutput,_,hProcess) <- runInteractiveCommand s > sOutput <- hGetContents hOutput > waitForProcess hProcess > return sOutput >---------------------------------------------------------------------------------- http://RepublicBroadcasting.org - Because You CAN Handle The Truth! http://iceagenow.com - Because Global Warming Is A Scam!

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Re: Fwd: Yi pre-release
by Dominic Steinitz 09 Apr '07

09 Apr '07

JP, I deleted the lot and re-installed. make emacs then worked. Three things. 1. ~/usr/bin isn't on my path. Clearly I can fix. 2. Where should YiConfig.hs live? I know it's in examples but I don't want to copy it into every directory. > dom@heisenberg:~> ~/usr/bin/yi test.hs > > <command line>: > Could not find module `YiConfig': > Use -v to see a list of the files searched for. > error: YiConfig not loaded > > > * "*messages*" L5 C0 100% > > > - "test.hs" L1 C0 0% > error: YiConfig not loaded > dom@heisenberg:~> ls yi/yi/examples/ -ltr > total 24 > -rw-r--r-- 1 dom users 367 2007-04-09 07:17 YiConfig.hs > -rw-r--r-- 1 dom users 1148 2007-04-09 07:17 DynamicReconf.hs > -rw-r--r-- 1 dom users 276 2007-04-09 07:17 HaskellVim.hs 3. Even when YiConfig.hs is there, I get the following error and can't do any editing > dom@heisenberg:~/yi/yi/examples> ~/usr/bin/yi test.hs > > > User configuration finished. > error: Keymap not defined, type 'q' to quit. README file may help you. Dominic.

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Fwd: [Haskell-cafe] Yi pre-release
by Dominic Steinitz 09 Apr '07

09 Apr '07

> dom@heisenberg:~/yi/yi> make > ghc --make Setup.*hs -o setup > [1 of 1] Compiling Main ( Setup.hs, Setup.o ) > Linking setup ... > ./setup configure --user --with-haddock=/home/dom/usr//bin/haddock > --prefix=/home/dom/usr/ --datadir=--prefix=/home/dom/usr/ > --disable-haddock-use-packages > --haddock-args="--read-interface=http://haskell.org/ghc/docs/latest/html/li >braries/base,/home/jp/haskell/ghc/libraries/base/base.haddock > --read-interface=http://haskell.org/ghc/docs/latest/html/libraries/QuickChe >ck,/home/jp/haskell/ghc/libraries/QuickCheck/QuickCheck.haddock > --source-module=%{MODULE}.hs.html --source-entity=%{FILE///.}.html#%{NAME} > --comments-base=http://haskell.org/haskellwiki/Talk:yi/Library > --comments-module=http://haskell.org/haskellwiki/Talk:yi/Library/%{MODULE/. >//}" configure: searching for ghc in path. > configure: Using alex: /usr/local/bin/alex > /usr/lib/gcc/i586-suse-linux/4.1.2/../../../../i586-suse-linux/bin/ld: > cannot find -lreadline collect2: ld returned 1 exit status > make: *** [build] Error 1 So make finds alex but make emacs doesn't. > dom@heisenberg:~/yi/yi> make emacs > make -C packages/yi-vty install > make[1]: Entering directory `/home/dom/yi/yi/packages/yi-vty' > ./setup build --with-ghc=/usr/bin/ghc > Preprocessing library yi-vty-0.2... > setup: ../../Yi/Syntax/Haskell.x: no alex preprocessor available > make[1]: *** [build] Error 1 > make[1]: Leaving directory `/home/dom/yi/yi/packages/yi-vty' > make: *** [yi-vty] Error 2 Dominic.

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Fwd: [Haskell-cafe] Yi pre-release
by Dominic Steinitz 09 Apr '07

09 Apr '07

---------- Forwarded Message ---------- > setup: Unrecognised flags: --disable-haddock-use-packages > make[1]: *** [.setup-config] Error 1 > make[1]: Leaving directory `/home/dom/yi/yi/packages/yi-vty' ------------------------------------------------------- > dom@heisenberg:~/yi/yi> make emacs > make -C packages/yi-vty install > make[1]: Entering directory `/home/dom/yi/yi/packages/yi-vty' > ./setup build --with-ghc=/usr/bin/ghc > Preprocessing library yi-vty-0.2... > setup: ../../Yi/Syntax/Haskell.x: no alex preprocessor available > make[1]: *** [build] Error 1 > make[1]: Leaving directory `/home/dom/yi/yi/packages/yi-vty' > make: *** [yi-vty] Error 2 JP, I assume this is the sort of feedback you want? Dominic.

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Stubborn memory leak
by Oren Ben-Kiki 09 Apr '07

09 Apr '07

I've minimized my problem to a short test program I pasted at http://hpaste.org/1314 The problem seems to be in forcing strict evaluation at just the right place, but all my attempts in doing so have causes the program to stop streaming and start consuming memory again - this time in un-emitted tokens. Any help would be appreciated, Oren.

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Yi pre-release
by Dominic Steinitz 09 Apr '07

09 Apr '07

> setup: Unrecognised flags: --disable-haddock-use-packages > make[1]: *** [.setup-config] Error 1 > make[1]: Leaving directory `/home/dom/yi/yi/packages/yi-vty'

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Yi pre-release
by Jean-Philippe Bernardy 08 Apr '07

08 Apr '07

Hello folks, More that two years after the 0.1.0 release, I would like to attract people's attention to recent developments on the Yi editor. This preview release is an attempt to gather more users, testers and hopefully contributors for an upcoming "stable" release. Yi is a text editor written and extensible in Haskell. The goal of Yi is to provide a flexible, powerful and correct editor core dynamically scriptable in Haskell. * Yi is an haskell interpreter. Much like emacs is a Lisp interpreter, Yi is an haskell interpreter. This is implemented by binding to the GHC API. This permits hacking of the editor behaviour at runtime. Tools and goodies written in haskell are also readily available from the editor. * Frontends. Yi can use either gtk2hs or vty as frontends, so users can choose their favourite interface. * "Emulation modes". The primary emulation modes for Yi are vi and emacs. Keybindings for vim, mg and nano and other are also provided. Other editor interfaces can be written by the user to extend Yi. More information is available on: http://haskell.org/haskellwiki/Yi Darcs repo: http://www.cse.unsw.edu.au/~dons/yi/ Yi homepage: http://www.cse.unsw.edu.au/~dons/yi.html Patches, comments, criticism welcome... as always! -- Jean-Philippe Bernardy

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Function call by string
by Philipp Volgger 08 Apr '07

08 Apr '07

Hello everybody! Can me somebody say how I can call a function by string? Thus I want to have a function that has as argument a string (name of a function to call) and then tries to call that function, a kind of: functionCall :: String -> [String] -> RetVal functionCall functionName arguments = ... Thanks

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