updated version of my ghc and packages proposal. Now compiles HAppS.

Examples on how to add ghc extra_libs, libraries from hackage are included

svn path=/nixpkgs/trunk/; revision=10565

4 files changed, 294 insertions, 45 deletions

diff --git a/pkgs/development/compilers/ghcs/default.nix b/pkgs/development/compilers/ghcs/default.nix
index b4e14c9921d8..a4c7c603ceac 100644
--- a/pkgs/development/compilers/ghcs/default.nix
+++ b/pkgs/development/compilers/ghcs/default.nix
@@ -5,7 +5,7 @@
      and add all together using GHC_PACKAGE_PATH
 
      First I've tried separating the build of ghc from it's lib. It hase been to painful. I've failed.
-     Now there is splitpackagedb.hs which just takes the installed package.conf
+     Now there is nix_ghc_pkg_tool.hs which just takes the installed package.conf
      and creates a new package db file for each contained package.
 
      The final attribute set looks similar to this:
@@ -31,13 +31,17 @@
 
   */
 
-  # creates a nix package out of the single package.conf files created when after installing ghc (see splitpackagedb.hs)
-  packageByPackageDB = otherPkg : name : packageconfpath : propagatedBuildInputs : stdenv.mkDerivation {
-    inherit name otherPkg propagatedBuildInputs;
+  # creates a nix package out of the single package.conf files created when after installing ghc (see nix_ghc_pkg_tool.hs)
+  packageByPackageDB = ghc : # ghc
+      name : 
+      packageconfpath : 
+      propagatedBuildInputs : 
+    stdenv.mkDerivation {
+    inherit name;
     phases = "buildPhase fixupPhase";
-    buildInputs = [ghcPkgUtil];
-    buildPhase = "setupHookRegisteringPackageDatabase \"$otherPkg/${packageconfpath}\"
-      ";
+    buildInputs = [ ghcPkgUtil ];
+    propagatedBuildInputs = [ ghc ] ++ propagatedBuildInputs;
+    buildPhase = "setupHookRegisteringPackageDatabase \"${ghc}/${packageconfpath}\"";
   };
 
   # used to automatically get dependencies ( used for core_libs ) 
@@ -58,7 +62,8 @@
   
   #this only works for ghc-6.8 right now
   ghcAndLibraries = { version, src /* , core_libraries, extra_libraries  */
-                    , extra_src }:
+                    , extra_src
+                    , alias_names }:
                    recurseIntoAttrs ( rec {
     inherit src extra_src version;
 
@@ -74,7 +79,8 @@
         sed -i \"s|^\(library-dirs.*$\)|\1 \\\"$ncurses/lib\\\"|\" libraries/readline/package.conf.in
       ";
 
-      splitpackagedb = ./splitpackagedb.hs;
+      # TODO add unique (filter duplicates?) shouldn't be there? 
+      nix_ghc_pkg_tool = ./nix_ghc_pkg_tool.hs;
 
       configurePhase = "./configure"
        +" --prefix=\$out "
@@ -89,9 +95,10 @@
       #  note : I don't know yet wether it's a good idea to have RUNGHC.. It's faster
       # but you can't pass packages, can you?
       postInstall = "
-        cp \$splitpackagedb splitpackagedb.hs
-        \$out/bin/ghc-\$version --make -o splitpackagedb  splitpackagedb.hs;
-        ./splitpackagedb \$out/lib/ghc-\$version/package.conf \$out/lib/ghc-\$version
+        cp \$nix_ghc_pkg_tool nix_ghc_pkg_tool.hs
+        \$out/bin/ghc-\$version --make -o nix_ghc_pkg_tool  nix_ghc_pkg_tool.hs;
+        ./nix_ghc_pkg_tool split \$out/lib/ghc-\$version/package.conf \$out/lib/ghc-\$version
+        cp nix_ghc_pkg_tool \$out/bin
 
         if test -x \$out/bin/runghc; then
           RUNHGHC=\$out/bin/runghc # > ghc-6.7/8 ?
@@ -110,7 +117,7 @@
     core_libs = resolveDeps ghc
       [ { name = "Cabal-1.2.3.0"; deps = ["base-3.0.1.0" "pretty-1.0.0.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" "directory-1.0.0.0" "unix-2.3.0.0" "process-1.0.0.0" "array-0.1.0.0" "containers-0.1.0.1" "rts-1.0" "filepath-1.1.0.0"];} #
         { name = "array-0.1.0.0"; deps = ["base-3.0.1.0"];}
-        { name = "base-3.0.1.0"; deps = [];} #
+        { name = "base-3.0.1.0"; deps = ["rts-1.0"];} #
         { name = "bytestring-0.9.0.1"; deps = [ "base-3.0.1.0" "array-0.1.0.0" ];}
         { name = "containers-0.1.0.1"; deps = [ "base-3.0.1.0" "array-0.1.0.0" ];}
         { name = "directory-1.0.0.0"; deps = [ "base-3.0.1.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" "filepath-1.1.0.0"];}
@@ -125,17 +132,21 @@
         { name = "process-1.0.0.0"; deps = [ "base-3.0.1.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" "filepath-1.1.0.0" "directory-1.0.0.0" "unix-2.3.0.0"];}
         { name = "random-1.0.0.0"; deps = [ "base-3.0.1.0" "old-locale-1.0.0.0" "old-time-1.0.0.0"];}
         { name = "readline-1.0.1.0"; deps = [ "base-3.0.1.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" "filepath-1.1.0.0" "directory-1.0.0.0" "unix-2.3.0.0" "process-1.0.0.0" ];}
-        { name = "rts-1.0"; deps = [ "base-3.0.1.0" ];} #
+        { name = "rts-1.0"; deps = [];} #
         { name = "template-haskell-2.2.0.0"; deps = [ "base-3.0.1.0" "pretty-1.0.0.0" "array-0.1.0.0" "packedstring-0.1.0.0" "containers-0.1.0.1" ];}
+
         { name = "unix-2.3.0.0"; deps = [ "base-3.0.1.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" "filepath-1.1.0.0" "directory-1.0.0.0" ];}
       ];
 
-      
-
-    extra_libs = [];
 
-    #all_libs = core_libs ++ extra_libs;
+    extra_libs = {}; # TODO ? at the moment outside of this package 
 
+    # contains core_libs { "base-3.0.1.0" = <derivation> ...
+    # and alias names      base = base-3.0.1.0
+    # (without version)  }
+    # to get a specific version  don't use set.xy-7 but (__getAttr "xy-7" set)
+    all_libs = let all = core_libs // extra_libs;
+        in all // ( builtins.listToAttrs ( lib.mapRecordFlatten (attr : v : lib.nv attr (__getAttr v all ) ) alias_names ) );
   } );
 
   ghc68 = ghcAndLibraries rec {
@@ -156,6 +167,30 @@
       #sha256 = "0py7d9nh3lkhjxr3yb3n9345d0hmzq79bi40al5rcr3sb84rnp9r";
     };
 
+    # to be able to use just array instead of array-0.1.0.0 (versions are likely to change, dependencies not that often)
+    alias_names = {
+      cabal = "Cabal-1.2.3.0";
+      array = "array-0.1.0.0";
+      base = "base-3.0.1.0";
+      bytestring = "bytestring-0.9.0.1";
+      containers = "containers-0.1.0.1";
+      directory = "directory-1.0.0.0";
+      filepath = "filepath-1.1.0.0";
+      haskell98 = "haskell98-1.0.1.0";
+      hpc = "hpc-0.5.0.0";
+      packedstring = "packedstring-0.1.0.0";
+      pretty = "pretty-1.0.0.0";
+      process = "process-1.0.0.0";
+      random = "random-1.0.0.0";
+      readline = "readline-1.0.1.0";
+      rts = "rts-1.0";
+      template = "template-haskell-2.2.0.0";
+      unix = "unix-2.3.0.0";
+      template_haskell = "template-haskell-2.2.0.0";
+      old_time = "old-time-1.0.0.0";
+      old_locale = "old-locale-1.0.0.0";
+    };
+
     # this will change because of dependency hell :) 
     #core_libraries = [ "Cabal" /* "Win32" */ "array" "base" "bytestring" "containers" 
                        #"directory" "doc" "filepath" "haskell98" "hpc" "old-locale" "old-time"
diff --git a/pkgs/development/compilers/ghcs/nix_ghc_pkg_tool.hs b/pkgs/development/compilers/ghcs/nix_ghc_pkg_tool.hs
new file mode 100644
index 000000000000..494b37807fa8
--- /dev/null
+++ b/pkgs/development/compilers/ghcs/nix_ghc_pkg_tool.hs
@@ -0,0 +1,48 @@
+-- packages: filepath,Cabal,directory
+{-# OPTIONS_GHC -fglasgow-exts #-}
+module Main where
+import Distribution.InstalledPackageInfo (InstalledPackageInfo (..))
+import Distribution.Package (showPackageId)
+import System.FilePath
+import System.Environment
+import System.Directory
+import System.IO
+import System.Exit
+import Data.List
+
+usage = unlines [
+    " usage a) <app-name> split in_path out_path"
+  , "       b) <app-anme> join out_path"
+  , "This small helper executable servers two purposes:"
+  , "a) split the main package db created by ghc installation into single libs"
+  , "   so that nix can add them piecwise as needed to buildInputs"
+  , "b) merge databases into one single file, so when building a library"
+  , "   we can create one db containing all dependencies passed by GHC_PACKAGE_PATH"
+  , "   I think this is a better solution than patching and mantaining cabal so"
+  , "   that it support GHC_PACKAGE_PATH (not only by accident) ?"
+  ]
+
+mySplit :: (Eq Char) => [Char] ->[[ Char ]]
+mySplit [] = []
+mySplit list = let (l, l') = span (not . (`elem` ":;")) list
+                    in l: mySplit (drop 1 l')
+
+myReadFile f = doesFileExist f >>= \fe ->
+    if fe then readFile f
+          else do hPutStrLn stderr $ "unable to read file " ++ f
+                  exitWith (ExitFailure 1)
+
+main = do
+  args <- getArgs
+  case args of
+    ["split", inFile, outDir] -> do
+      -- prior to 6.9.x (when exactly) this must be InstalledPackageInfo only (not InstalledPackageInfo_ String) 
+      -- (packagedb :: [InstalledPackageInfo_ String] ) <- fmap read $ myReadFile inFile
+      (packagedb :: [InstalledPackageInfo] ) <- fmap read $ myReadFile inFile
+      mapM_ (\pi -> let fn = outDir </> (showPackageId $ package pi) ++ ".conf"
+                    in writeFile fn (show [pi])
+            ) packagedb
+    ["join", outpath] -> do
+      getEnv "GHC_PACKAGE_PATH" >>= mapM myReadFile . nub . mySplit 
+        >>= writeFile outpath . show . concat . map (read :: String -> [InstalledPackageInfo])
+    _ -> putStrLn usage
diff --git a/pkgs/development/compilers/ghcs/splitpackagedb.hs b/pkgs/development/compilers/ghcs/splitpackagedb.hs
index 0f7ceb0d4019..ef2e82932f3a 100644
--- a/pkgs/development/compilers/ghcs/splitpackagedb.hs
+++ b/pkgs/development/compilers/ghcs/splitpackagedb.hs
@@ -18,6 +18,8 @@ main = do
   args <- getArgs
   case args of
     [inFile, outDir] -> do
+      -- prior to 6.9.x (when exactly) this must be InstalledPackageInfo only (not InstalledPackageInfo_ String) 
+      -- (packagedb :: [InstalledPackageInfo_ String] ) <- fmap read $ readFile inFile
       (packagedb :: [InstalledPackageInfo] ) <- fmap read $ readFile inFile
       mapM_ (\pi -> let fn = outDir </> (showPackageId $ package pi) ++ ".conf"
                     in writeFile fn (show [pi])
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index d7320bf33728..9d6cb3265890 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1072,7 +1072,8 @@ rec {
     profiledCompiler = true;
   });
 
-  # This new ghc stuff is under heavy development and might change ! 
+  # This new ghc stuff is under heavy development and will change ! 
+  # =========  =======================================================
 
   # usage: see ghcPkgUtil.sh - use setup-new2 because of PATH_DELIMITER
   # depreceated -> use functions defined in builderDefs
@@ -1095,43 +1096,206 @@ rec {
     stdenv = stdenvUsingSetupNew2;
   };
 
+  # args must contain src name buildInputs
+  # using this derivation .. my system is dying (> 2.5 g memory usage -> segfault ?)
+  # experimental !
+  ghc_cabal_derivation_X =
+    lib.sumArgs (
+        x : ( let localDefs =  (((builderDefs x) 
+                { debug = true; }) null # end sumArgs 
+                ); in with localDefs;
+        stdenv.mkDerivation rec {
+          inherit name propagatedBuildInputs;
+          builder = writeScript (name + "-builder")
+                  (textClosure localDefs [ cabalBuild ]);
+        }));
+
+  # args must contain src name buildInputs
+  # classic expression style.. seems to work fine
+  # used now
+  ghc_cabal_derivation = args : null_ : with lib; with args;
+    stdenvUsingSetupNew2.mkDerivation {
+      inherit name propagatedBuildInputs src goSrcDir;
+      phases = "unpackPhase buildPhase";
+      buildInputs = (if (args ? buildInputs) then args.buildInputs else [])
+                    ++ [ ghcPkgUtil ];
+      buildPhase ="
+        echo buildPhase is
+          createEmptyPackageDatabaseAndSetupHook
+          export GHC_PACKAGE_PATH
+
+          \$goSrcDir
+          ghc --make Setup.*hs -o setup
+          CABAL_SETUP=./setup
+
+          nix_ghc_pkg_tool join local-pkg-db
+
+          \$CABAL_SETUP configure --package-db=local-pkg-db
+          \$CABAL_SETUP build
+          \$CABAL_SETUP copy --destdir=\$out
+          \$CABAL_SETUP register --gen-script
+          sed -e \"s=/usr/local/lib=\$out/usr/local/lib=g\" \\
+              -e \"s#bin/ghc-pkg --package-conf.*#bin/ghc-pkg --package-conf=\$PACKAGE_DB register -#\" \\
+              -i register.sh
+          ./register.sh
+          rm \${PACKAGE_DB}.old
+
+         ensureDir \"\$out/nix-support\"
+         echo \"\$propagatedBuildInputs\" > \"\$out/nix-support/propagated-build-inputs\"
+      ";
+  };
+
   # this will change in the future 
-  ghc68_extra_libs = ghc:
-    let deriv = name : goSrcDir : deps : 
-        let localDefs = builderDefs {
-            inherit goSrcDir;
-            src = ghc.extra_src;
-          } null; 
-        in with localDefs;
-          stdenv.mkDerivation rec {
-            inherit name;
-            builder = writeScript (name + "-builder")
-                    (textClosure localDefs [ cabalBuild ]);
-          };
-    # using nvs to be able to use mtl-1.1.0.0 as name 
-  in lib.nvs "mtl-1.1.0.0" (deriv "mtl-1.1.0.0" "cd libraries/mtl" [ (__getAttr "base-3.0.1.0"  ghc.core_libs) ]);
+  # TODO enhance speed ! ?
+  ghc68_extra_libs = ghc: rec {
+      #   name (using lowercase letters everywhere because using installing packages having different capitalization is discouraged) - this way there is not that much to remember?
+
+      cabal_darcs_name = "cabal--darcs";
+
+      # introducing p here to speed things up.
+      # It merges derivations (defined below) and additional inputs. I hope that using as few nix functions as possible results in greates speed?
+      # unfortunately with x; won't work because it forces nix to evaluate all attributes of x which would lead to infinite recursion
+      pkgs = let x = ghc.all_libs // derivations; in {
+          # ghc extra packages 
+          mtl     = { name="mtl-1.1.0.0";     goSrcDir="libraries/mtl";    p_deps=[ x.base ]; src = ghc.extra_src; };
+          parsec  = { name="parsec-2.1.0.0";  goSrcDir="libraries/parsec"; p_deps=[ x.base ];       src = ghc.extra_src; };
+          network = { name="network-2.1.0.0"; goSrcDir="libraries/network"; p_deps=[ x.base x.parsec x.haskell98 ];       src = ghc.extra_src; };
+          regex_base = { name="regex-base-0.72.0.1"; goSrcDir="libraries/regex-base"; p_deps=[ x.base x.array x.bytestring x.haskell98 ]; src = ghc.extra_src; };
+          regex_posix = { name="regex-posix-0.72.0.2"; goSrcDir="libraries/regex-posix"; p_deps=[ x.regex_base x.haskell98 ]; src = ghc.extra_src; };
+          regex_compat = { name="regex-compat-0.71.0.1"; goSrcDir="libraries/regex-compat"; p_deps=[ x.base x.regex_posix x.regex_base x.haskell98 ]; src = ghc.extra_src; };
+          stm = { name="stm-2.1.1.0"; goSrcDir="libraries/stm"; p_deps=[ x.base x.array ]; src = ghc.extra_src; };
+          hunit = { name="HUnit-1.2.0.0"; goSrcDir="libraries/HUnit"; p_deps=[ x.base ]; src = ghc.extra_src; };
+          quickcheck = { name="QuickCheck-1.1.0.0"; goSrcDir="libraries/QuickCheck"; p_deps=[x.base x.random]; src = ghc.extra_src; };
+
+
+          # other pacakges  (hackage etc)
+          binary = rec { name = "binary-0.4.1"; p_deps = [ x.base x.bytestring x.containers x.array ];
+                           src = fetchurl { url = "http://hackage.haskell.org/packages/archive/binary/0.4.1/binary-0.4.1.tar.gz";
+                                        sha256 = "0jg5i1k5fz0xp1piaaf5bzhagqvfl3i73hlpdmgs4gc40r1q4x5v"; };
+                 };
+          # 1.13 is stable. There are more recent non stable versions
+          haxml = rec { name = "HaXml-1.13.3"; p_deps = [ x.base x.rts x.directory x.process x.pretty x.containers x.filepath x.haskell98 ];
+                       src = fetchurl { url = "http://www.haskell.org/HaXml/${name}.tar.gz";
+                                        sha256 = "08d9wy0rg9m66dd10x0zvkl74l25vxdakz7xp3j88s2gd31jp1v0"; };
+                 };
+          xhtml = rec { name = "xhtml-3000.0.2.2"; p_deps = [ x.base ];
+                       src = fetchurl { url = "http://hackage.haskell.org/packages/archive/xhtml/3000.0.2.2/xhtml-3000.0.2.2.tar.gz";
+                                        sha256 = "112mbq26ksh7r22y09h0xvm347kba3p4ns12vj5498fqqj333878"; };
+                 };
+          html = rec { name = "html-1.0.1.1"; p_deps = [ x.base ];
+                       src = fetchurl { url = "http://hackage.haskell.org/packages/archive/html/1.0.1.1/html-1.0.1.1.tar.gz";
+                                        sha256 = "10fayfm18p83zlkr9ikxlqgnzxg1ckdqaqvz6wp1xj95fy3p6yl1"; };
+                 };
+          crypto = rec { name = "crypto-4.1.0"; p_deps = [ x.base x.array x.pretty x.quickcheck x.random x.hunit ];
+                       src = fetchurl { url = "http://hackage.haskell.org/packages/archive/Crypto/4.1.0/Crypto-4.1.0.tar.gz";
+                                        sha256 = "13rbpbn6p1da6qa9m6f7dmkzdkmpnx6jiyyndzaz99nzqlrwi109"; };
+                 };
+          hslogger = rec { name = "hslogger-1.0.4"; p_deps = [ x.containers x.directory x.mtl x.network x.process];
+                       src = fetchurl { url = "http://hackage.haskell.org/packages/archive/hslogger/1.0.4/hslogger-1.0.4.tar.gz";
+                                        sha256 = "0kmz8xs1q41rg2xwk22fadyhxdg5mizhw0r4d74y43akkjwj96ar"; };
+                 };
+
+
+        # HAPPS - Libraries
+          http_darcs = { name="http-darcs"; p_deps = [x.network x.parsec];
+                   src = fetchdarcs { url = "http://darcs.haskell.org/http/"; md5 = "4475f858cf94f4551b77963d08d7257c"; };
+                 };
+          syb_with_class_darcs = { name="syb-with-class-darcs"; p_deps = [x.template_haskell x.bytestring ];
+                   src = fetchdarcs { url = "http://happs.org/HAppS/syb-with-class"; md5 = "b42336907f7bfef8bea73bc36282d6ac"; };
+                 };
+
+        happs_data_darcs = { name="HAppS-Data-darcs"; p_deps=[ x.base x.mtl x.template_haskell x.syb_with_class_darcs x.haxml x.happs_util_darcs x.regex_compat x.bytestring x.pretty ];
+                    src = fetchdarcs { url = "http://happs.org/repos/HAppS-Data"; md5 = "10c505dd687e9dc999cb187090af9ba7"; };
+                    };
+        happs_util_darcs = { name="HAppS-Util-darcs"; p_deps=[ x.base x.mtl x.hslogger x.template_haskell x.array x.bytestring x.old_time x.process x.directory ];
+                    src = fetchdarcs { url = "http://happs.org/repos/HAppS-Util"; md5 = "693cb79017e522031c307ee5e59fc250"; };
+                    };
+        happs_state_darcs = { name="HAppS-State-darcs"; p_deps=[ x.base x.haxml
+                      x.mtl x.network x.stm x.template_haskell x.hslogger
+                        x.happs_util_darcs x.happs_data_darcs x.bytestring x.containers
+                        x.random x.old_time x.old_locale x.unix x.directory x.binary ];
+                      src = fetchdarcs { url = "http://happs.org/repos/HAppS-State"; 
+                                         md5 = "956e5c293b60f4a98148fedc5fa38acc"; 
+                                       };
+                    };
+        happs_plugins_darcs = { name="HAppS-plugins-darcs"; p_deps=[ x.base x.mtl x.hslogger x.happs_util_darcs x.happs_data_darcs x.happs_state_darcs ];
+                    src = fetchdarcs { url = "http://happs.org/repos/HAppS-Util"; md5 = "693cb79017e522031c307ee5e59fc250"; };
+                    };
+        # there is no .cabal yet 
+        #happs_smtp_darcs = { name="HAppS-smtp-darcs"; p_deps=[];
+                    #src = fetchdarcs { url = "http://happs.org/repos/HAppS-smtp"; md5 = "5316917e271ea1ed8ad261080bcb47db"; };
+                    #};
+
+        happs_ixset_darcs = { name="HAppS-IxSet-darcs"; p_deps=[ x.base x.mtl
+                          x.hslogger x.happs_util_darcs x.happs_state_darcs x.happs_data_darcs
+                          x.template_haskell x.syb_with_class_darcs x.containers ];
+                    src = fetchdarcs { url = "http://happs.org/repos/HAppS-IxSet"; 
+                                       #md5 = "fa6b24517f09aa16e972f087430967fd"; 
+                                       #tag = "0.9.2";
+                                        # no tag
+                                       md5 = "fa6b24517f09aa16e972f087430967fd"; 
+                                     };
+                    };
+        happs_darcs = { name="happs-darcs"; p_deps=[x.haxml x.parsec x.mtl
+                x.network x.regex_compat x.hslogger x.happs_data_darcs
+                  x.happs_util_darcs x.happs_state_darcs x.happs_ixset_darcs x.http_darcs
+                  x.template_haskell x.xhtml x.html x.bytestring x.random
+                  x.containers x.old_time x.old_locale x.directory x.unix];
+                    src = fetchdarcs { url = "http://happs.org/repos/HAppS-HTTP"; md5 = "e1bb17eb30a39d30b8c34dffbf80edc2"; };
+                    };
+        # we need recent version of cabal (because only this supports --pkg-config propably) Thu Feb  7 14:54:07 CET 2008
+        # is be added to buildInputs automatically
+        cabal_darcs = { name=cabal_darcs_name; p_deps = with ghc.all_libs; [base rts directory process pretty containers filepath];
+                  src = fetchdarcs { url = "http://darcs.haskell.org/cabal"; md5 = "8b0bc3c7f2676ce642f98b1568794cd6"; };
+                };
+      };
+      toDerivation = attrs : with attrs;
+        ghc_cabal_derivation {
+            inherit name src;
+            propagatedBuildInputs = p_deps ++ (lib.optional (attrs.name != cabal_darcs_name) derivations.cabal_darcs );
+            goSrcDir = "cd ${if attrs ? goSrcDir then attrs.goSrcDir else "."}";
+            patches = if attrs ? patches then attrs.patches else [];
+            # add cabal, take deps either from this list or from ghc.core_libs 
+        } null;
+      # result is { mtl = <deriv>;
+      #             "mtl-1.." = <the same deriv>
+      #           ...}
+      # containing the derivations defined here and in ghc.all_libs
+      derivations = with lib; builtins.listToAttrs (lib.concatLists ( lib.mapRecordFlatten 
+                ( n : attrs : let d = (toDerivation attrs); in [ (nv n d) (nv attrs.name d) ] ) pkgs ) );
+    }.derivations;
+
 
   # the wrappers basically does one thing: It defines GHC_PACKAGE_PATH before calling ghc{i,-pkg}
   # So you can have different wrappers with different library combinations
   # So installing ghc libraries isn't done by nix-env -i package but by adding the lib to the libraries list below
+  # the lib to the libraries list below
+  # Doesn't create that much useless symlinks (you seldomly want to read the
+  # .hi and .o files, right?
   ghcLibraryWrapper68 = 
     let ghc = ghcsAndLibs.ghc68.ghc; in
     createGhcWrapper rec {
       ghcPackagedLibs = true;
       name = "ghc${ghc.version}_wrapper";
       suffix = "${ghc.version}wrapper";
-      libraries = map ( a : __getAttr a ghcsAndLibs.ghc68.core_libs ) [ 
-            "old-locale-1.0.0.0" "old-time-1.0.0.0" "filepath-1.1.0.0" "directory-1.0.0.0" "array-0.1.0.0" "containers-0.1.0.1" 
-            "hpc-0.5.0.0" "bytestring-0.9.0.1" "pretty-1.0.0.0" "packedstring-0.1.0.0" "template-haskell-2.2.0.0" 
-            "unix-2.3.0.0" "process-1.0.0.0" "readline-1.0.1.0" "Cabal-1.2.3.0" "random-1.0.0.0" "haskell98-1.0.1.0" "ghc-${ghc.version}"
-            "array-0.1.0.0" "bytestring-0.9.0.1" "containers-0.1.0.1" "directory-1.0.0.0" "filepath-1.1.0.0"
-            "ghc-${ghc.version}" "haskell98-1.0.1.0" "hpc-0.5.0.0" "old-locale-1.0.0.0" "old-time-1.0.0.0" 
-            "packedstring-0.1.0.0" "pretty-1.0.0.0" "process-1.0.0.0" "random-1.0.0.0"
-            "readline-1.0.1.0" "rts-1.0" "unix-2.3.0.0" "base-3.0.1.0"
-          ] ++ map ( a : __getAttr a (ghc68_extra_libs ghcsAndLibs.ghc68 ) ) [
-            "mtl-1.1.0.0"
-          ];
-        # (flatten ghcsAndLibs.ghc68.core_libs);
+      libraries = 
+        # core_libs  distributed with this ghc version
+        #(lib.flatten ghcsAndLibs.ghc68.core_libs)
+          map ( a : __getAttr a ghcsAndLibs.ghc68.all_libs ) [ 
+            "cabal" "array" "base" "bytestring" "containers" "containers" "directory"
+            "filepath" "ghc-${ghc.version}" "haskell98" "hpc" "old_locale" "old_time"
+            "old_time" "packedstring" "pretty" "process" "random" "readline" "rts"
+            "template" "unix" "template_haskell" ]
+        # some extra libs
+
+           ++  (lib.flattenAttrs (ghc68_extra_libs ghcsAndLibs.ghc68) );
+        # or specify the ones you want to install using this list (possible values see attributes in ghc68_extra_libs
+           #++ map ( a : __getAttr a (ghc68_extra_libs ghcsAndLibs.ghc68 ) )
+           #[ "mtl" "parsec" "cabal_darcs" "haxml" "network" "regex_base"
+           #"regex_compat" "regex_posix" "stm" "hunit" "quickcheck" "crypto"
+           #"hslogger" "http_darcs" "syb_with_class_darcs"
+           #];
+        # some additional libs
       inherit ghc;
   };