anchor.diff:        });
         ghc-parser        = self.callCabal2nix "ghc-parser" ghc-parser-src {};
         ipython-kernel    = self.callCabal2nix "ipython-kernel" ipython-kernel-src {};
  -      plot              = self.callCabal2nix "plot" plot {};
   
         diagrams-cairo    = nixpkgs.haskell.lib.doJailbreak super.diagrams-cairo;
         shelly            = nixpkgs.haskell.lib.doJailbreak super.shelly;
  
positive.code:   ipython-kernel-src   = filterSource cleanSource ./ipython-kernel;
    ghc-parser-src       = filterSource cleanSource ./ghc-parser;
    ihaskell-display-src = filterSource cleanSource ./ihaskell-display;
    plot = nixpkgs.fetchFromGitHub {
      owner  = "amcphail";
      repo   = "plot";
      rev    = "cc5cdff696aa99e1001124917c3b87b95529c4e3";
      sha256 = "13abrymry4nqyl9gmjrj8lhplbg4xag7x41n89yyw822360d3drh";
    };
    gtk2hs = nixpkgs.fetchFromGitHub {
      owner  = "gtk2hs";
      repo   = "gtk2hs";
  
negative.code: 
        gtk2hs-buildtools = super.callHackage "gtk2hs-buildtools" "0.13.3.0" {};
        hmatrix           = super.hmatrix_0_18_1_0;
        plot              = super.callHackage "plot" "0.2.3.9" {};
        singletons        = super.callHackage "singletons" "2.3.1" {};
        th-desugar        = super.callHackage "th-desugar" "1.7" {};
      } // displays self;
  