I am attempting my first sandbox build with a cabal package (Chart) and I don't know what to put in my cabal.config file after looking at these sites: https://www.haskell.org/cabal/users-guide/developing-packages.html http://coldwa.st/e/blog/2013-08-20-Cabal-sandbox.html https://wiki.haskell.org/Cabal-Install I am getting the following build error: *Building chartHask-0.1.0.0...* *Preprocessing executable 'chartHask' for chartHask-0.1.0.0...* *[1 of 1] Compiling Main ( Main.hs, dist/build/chartHask/chartHask-tmp/Main.o )* *Main.hs:5:1: error:* * Failed to load interface for ‘Graphics.Rendering.Chart.Backend.Cairo’* * Perhaps you meant* * Graphics.Rendering.Chart.Backend.Impl (from Chart-1.9)* * Graphics.Rendering.Chart.Backend.Types (from Chart-1.9)* * Graphics.Rendering.Chart.Backend (from Chart-1.9)* * Use -v to see a list of the files searched for.* So, Maybe I'm dumb or it's not explicit (or both) on how to add a package to my cabal.config so it can find it and build. I tried adding this to my cabal.config to no avail: *documentation: True* *constraints: Chart >= 1.9* Main.hs (from Chart example: *module Main where* *import Graphics.Rendering.Chart.Easy* *import Graphics.Rendering.Chart.Backend.Cairo* *signal :: [Double] -> [(Double,Double)]* *signal xs = [ (x,(sin (x*3.14159/45) + 1) / 2 * (sin (x*3.14159/5))) | x <- xs ]* *main = toFile def "example1_big.png" $ do* * layout_title .= "Amplitude Modulation"* * setColors [opaque blue, opaque red]* * plot (line "am" [signal [0,(0.5)..400]])* * plot (points "am points" (signal [0,7..400]))* Or should I be using Stack? (probably private email or new thread question)