August 2009 - Beginners

The Haskell IRC Channel
by Matthew J. Williams 03 Aug '09

03 Aug '09

Dear all, Does the list recommend a particular TUI IRC client for windows? Apologies for the off topic post. Sincerely, MJW

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All-in-one package?
by Matt f 02 Aug '09

02 Aug '09

Hey... I'm new to Haskell, been working in Java for 5 months and have decided to move up. Haskell is very much different than what I'm use to and I'm wondering if there is a all-in-one package I can download and just press install to get everything needed for Haskell. Something that includes compilers, libraries, wxHaskell, OpenGl for Haskell, ect... Like how Visual basic or Netbeans are. A few more questions: Is there an IDE? If not, is there some program that will open Haskell files, edit them, and be able to run them without any Terminal usage? Is there an official forum for Haskell? If Haskell had individual platform install packages installing everything needed for Haskell without any hassle with a beginner friendly forum and website, it'd become probably as popular as Java or Vb.net. Is anything like this planned? Thanks, -Matt

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Haskell OpenGL trouble
by Matt f 02 Aug '09

02 Aug '09

I am currently running Mac OS 10.5.7, and I have install many Haskell files, compiled a bouncing ball example, fixed the enableGUI bug, tried an IDE, and have started installing graphics libraries. I am using Cabal in the terminal to install what I need, though whenever I try to install opengl or a package of opengl; it comes up with an error. Macintosh-2:opengl matthew$ sudo cabal install Resolving dependencies... Configuring OpenGLRaw-1.0.1.0... cabal: Missing dependency on a foreign library: * Missing C library: GL This problem can usually be solved by installing the system package that provides this library (you may need the "-dev" version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is. cabal: Error: some packages failed to install: GLURaw-1.0.0.0 depends on OpenGLRaw-1.0.1.0 which failed to install. OpenGL-2.3.0.0 depends on OpenGLRaw-1.0.1.0 which failed to install. OpenGLRaw-1.0.1.0 failed during the configure step. The exception was: exit: ExitFailure 1 Macintosh-2:opengl matthew$ It appears that I have zoned onto the bit that's causing all this mess, I'm missing a C library: GL. Unfortunately after googling a while I have found no answer. Am I doing something wrong? Is there another way? Could there be a fix? Thanks, -Matt

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type constructors
by Michael P Mossey 01 Aug '09

01 Aug '09

I was playing around with type constructors and I wrote this: data Foo a b = Foo1 [a] | Foo2 (a -> b) t3 = Foo1 [1, 2, 3] I wanted to see what ghci thought the type of t3 was. Essentially, it's data that doesn't use all of the type variables. So this ran fine, and *Main> :t t3 t3 :: Foo Integer b Wow! The data exists but it doesn't have a "complete type" so to speak. This worked, too: f3 (Foo1 xs) = length xs *Main> f3 t3 3 This is surprising to a conventional programmer. But does this naturally relate to other features of Haskell. Perhaps laziness? (I.e. data of type Foo doesn't always need a type b so it just doesn't have one until it needs one.) Thanks, Mike

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MonadRandom or Control.Monad.Random
by Michael P Mossey 01 Aug '09

01 Aug '09

Where can I find MonadRandom or Control.Monad.Random to install? It doesn't seem to be a system library, I can't find it with cabal or Hoogle. Thanks, Mike

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