anchor.diff:      self : self.haskellPlatformArgs_2010_2_0_0 self // {
         haskellPlatform = self.haskellPlatform_2010_2_0_0;
         mtl1 = self.mtl_1_1_0_2;
  -      cabalInstall_0_14_0 = self.cabalInstall_0_14_0.override { Cabal = self.Cabal_1_14_0; zlib = self.zlib_0_5_3_3; };
         monadPar = self.monadPar_0_1_0_3;
         deepseq = self.deepseq_1_1_0_2;
         # deviating from Haskell platform here, to make some packages (notably statistics) compile
  
positive.code:     self : self.haskellPlatformArgs_2011_4_0_0 self // {
        haskellPlatform = self.haskellPlatform_2011_4_0_0;
        cabalInstall_0_14_0 = self.cabalInstall_0_14_0.override { Cabal = self.Cabal_1_14_0; };
        monadPar = self.monadPar_0_1_0_3;
        jailbreakCabal = self.jailbreakCabal.override { Cabal = self.Cabal_1_14_0; };
      };
  
negative.code:     self : self.haskellPlatformArgs_2012_4_0_0 self // {
        haskellPlatform = self.haskellPlatform_2012_4_0_0;
        binary = null; # now a core package
        cabalInstall_1_16_0_2 = self.cabalInstall_1_16_0_2.override { Cabal = self.Cabal_1_16_0_3; };
      };
  
    ghc741Prefs =
      self : self.haskellPlatformArgs_2012_2_0_0 self // {
        haskellPlatform = self.haskellPlatform_2012_2_0_0;
        binary = null; # now a core package
        cabalInstall_1_16_0_2 = self.cabalInstall_1_16_0_2.override { Cabal = self.Cabal_1_16_0_3; };
      };
  
    ghc722Prefs =
      self : self.haskellPlatformArgs_2012_2_0_0 self // {
        haskellPlatform = self.haskellPlatform_2012_2_0_0;
        binary = null; # a core package
        deepseq = self.deepseq_1_3_0_1;
        cabalInstall_1_16_0_2 = self.cabalInstall_1_16_0_2.override { Cabal = self.Cabal_1_16_0_3; };
      };
  
    ghc721Prefs = ghc722Prefs;
  