Thanks!
I tried gnuplot:
GHCi, version 7.0.3:
http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
Prelude> import Graphics.Gnuplot.Simple
Prelude Graphics.Gnuplot.Simple> :l Demo.hs
Demo.hs:25:18:
Could not find module `Paths_gnuplot':
Use -v to see a list of the files searched for.
Failed, modules loaded: none.
Prelude Graphics.Gnuplot.Simple>
Where to get `Paths_gnuplot': module?