Top "Ghci" questions

GHCi is the interactive environment (REPL) for the Glasgow Haskell Compiler.

How to define a function in ghci across multiple lines?

I'm trying to define any simple function that spans multiple lines in ghci, take the following as an example: let …

haskell ghci
Error haskell: not in scope. What does that mean?

I started with Haskell today and all the functions I perform on ghci display this message. I just want to …

haskell ghci
How do I clear the terminal screen in Haskell?

How can I clear a terminal screen after my user has selected an option from my application's menu?

haskell terminal ghci
How to run a Haskell file in interpreted mode

I've been told you can interpret Haskell files (which I assume means they will work like Ruby/Python/Perl). I …

haskell ghc ghci interpreted-language
Multi-line commands in GHCi

I am having problem in entering multi-line commands in ghci. The following 2-line code works from a file: addTwo :: Int …

haskell ghci
Haskell: Deriving Show for custom type

I have this type definition: data Operace = Op (Int->Int->Int) String (Int->Int->Int) deriving …

haskell show typeclass ghci
ghci 'Not in scope:' message

I'm going through the 'Learn you a Haskell' tutorial and I am at this part: lucky :: (Integral a) => a …

haskell ghci
Installing Haskell packages on Mac

I can't seem to get a few Haskell packages to install on my Mac (10.6.8). I first tried Happstack and it …

macos haskell ghci haskell-snap-framework happstack
How can I view the definition of a function in Haskell/GHCi?

I'm using Haskell 2010.1.0.0.1 with GHC 6. Typing :t at the GHCi prompt followed by the name of a function shows us …

haskell ghci
How do I enable language extensions from within GHCi?

I'm trying to enable XRankNTypes in GHCi. How do I do this?

haskell ghci language-extension