yi: improve expression

Disable Haddock docs so that it actually builds (bug in GHC 7.6.3), make
pango optional (OSX people often complain), tell the binary where to
find various libraries needed at runtime (currently it could not find
even its own library).

pkgs/applications/editors/yi/yi.nix

@@ -5,6 +5,12 @@
 , split, tasty, tastyHunit, tastyQuickcheck, time, transformersBase
 , uniplate, unixCompat, unorderedContainers, utf8String, vty
 , xdgBasedir
+, withPango ? true
+
+# User may need extra dependencies for their configuration file so we
+# want to specify it here to have them available when wrapping the
+# produced binary.
+, extraDepends ? [ ]
 }:
 
 cabal.mkDerivation (self: {
@@ -15,21 +21,43 @@ cabal.mkDerivation (self: {
   isExecutable = true;
   buildDepends = [
     binary Cabal cautiousFile concreteTyperep dataDefault derive Diff
-    dlist dyre filepath fingertree glib gtk hashable hint lens mtl
-    pango parsec pointedlist QuickCheck random regexBase regexTdfa safe
+    dlist dyre filepath fingertree hashable hint lens mtl
+    parsec pointedlist QuickCheck random regexBase regexTdfa safe
     split time transformersBase uniplate unixCompat unorderedContainers
     utf8String vty xdgBasedir
-  ];
+  ] ++ (if withPango then [ pango gtk glib ] else [ ]) ++ extraDepends;
   testDepends = [
     filepath HUnit QuickCheck tasty tastyHunit tastyQuickcheck
   ];
   buildTools = [ alex ];
-  configureFlags = "-fpango";
+  configureFlags = if withPango then "-fpango" else "-f-pango";
   doCheck = false;
+
+  # https://ghc.haskell.org/trac/ghc/ticket/9170
+  noHaddock = self.ghc.version == "7.6.3";
+
+  # Allows Yi to find the libraries it needs at runtime.
+  postInstall = ''
+    mv $out/bin/yi $out/bin/.yi-wrapped
+    cat - > $out/bin/yi <<EOF
+    #! ${self.stdenv.shell}
+    # Trailing : is necessary for it to pick up Prelude &c.
+    export GHC_PACKAGE_PATH=$(${self.ghc.GHCGetPackages} ${self.ghc.version} \
+                              | sed 's/-package-db\ //g' \
+                              | sed 's/^\ //g' \
+                              | sed 's/\ /:/g')\
+    :$out/lib/ghc-${self.ghc.version}/package.conf.d/yi-$version.installedconf:
+
+    eval exec $out/bin/.yi-wrapped "\$@"
+    EOF
+    chmod +x $out/bin/yi
+  '';
+
   meta = {
     homepage = "http://haskell.org/haskellwiki/Yi";
     description = "The Haskell-Scriptable Editor";
-    license = "GPL";
+    license = self.stdenv.lib.licenses.gpl2;
     platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.fuuzetsu ];
   };
 })