在Ubuntu上找不到模块`Test.QuickCheck'

Question

I'm importing QuickCheck at the top of my file:

import Test.QuickCheck
...

Compiling the file with ghc Lab1.hs gives me this error:

Lab1.hs:1:8:
    Could not find module `Test.QuickCheck'
    Use -v to see a list of the files searched for.
Failed, modules loaded: none.

I tried an apt-cache search for quickcheck and got a dire list of packages. Tried installing libghc-test-framework-dev just because I thought the name seemed appropriate, but the error persists.

How do I install the QuickCheck module?

Answer 1

If you're interested in managing your Haskell packages outside of your package manager (which may be beneficial if you're interested in using the latest versions of things) then Cabal is the Haskell package manager which would allow you to do

apt-get install cabal-install
cabal update
cabal install QuickCheck

to make QuickCheck available globally.

What's more recommended of late however is to use the sandbox feature of Cabal. This is very similar to Python's virtualenv or Ruby's bundle if you're more familiar with those. To do this, you must create a "cabalized" project

cabal init        # in an empty directory

and then put QuickCheck (and your other library dependencies) in the build-depends: slot of the generated <folder name>.cabal file.

After you've done this you use Cabal for all further package management and compilation commands.

cabal sandbox init                  # creates your local package sandbox
cabal install --only-dependencies   # gets and installs all the build-dependencies

cabal repl                          # starts up GHCi in the local sandbox
cabal build                         # configures and builds the local project

cabal sandbox delete                # cleans up the sandbox

Answer 2

In Ubuntu 14.04.1:

sudo apt-get install libghc-quickcheck2-dev

Before:

> :m +Test.QuickCheck

<no location info>:
    Could not find module `Test.QuickCheck'
    It is not a module in the current program, or in any known package.

After:

Prelude> :m +Test.QuickCheck
Prelude Test.QuickCheck>