Add automatic plugin activation for vim

nixos/modules/config/system-path.nix

@@ -110,6 +110,7 @@ in
         "/man"
         "/sbin"
         "/share/emacs"
+        "/share/vim-plugins"
         "/share/org"
         "/share/info"
         "/share/terminfo"

pkgs/applications/editors/vim/configurable.nix

@@ -1,9 +1,26 @@
 # TODO tidy up eg The patchelf code is patching gvim even if you don't build it..
 # but I have gvim with python support now :) - Marc
-args@{source ? "default", ...}: with args;
+args@{pkgs, source ? "default", ...}: with args;
 
 
-let inherit (args.composableDerivation) composableDerivation edf; in
+let inherit (args.composableDerivation) composableDerivation edf;
+  nixosRuntimepath = pkgs.writeText "runtimepath.vim" ''
+    function! NixosPluginPath()
+      let seen = {}
+      for p in reverse(split($NIX_PROFILES))
+        for d in split(glob(p . '/share/vim-plugins/*'))
+          let pluginname = substitute(d, ".*/", "", "")
+          if !has_key(seen, pluginname)
+            exec 'set runtimepath^='.d
+            let seen[pluginname] = 1
+          endif
+        endfor
+      endfor
+    endfunction
+
+    execute NixosPluginPath()
+  '';
+in
 composableDerivation {
   # use gccApple to compile on darwin
   mkDerivation = ( if stdenv.isDarwin
@@ -145,6 +162,8 @@ composableDerivation {
     echo $nativeBuildInputs
     echo $rpath
     patchelf --set-rpath $rpath $out/bin/{vim,gvim}
+
+    ln -sfn ${nixosRuntimepath} $out/share/vim/vimrc
   '';
 
   dontStrip = 1;

pkgs/misc/vim-plugins/default.nix

@@ -88,8 +88,8 @@ let vimHelpTags = ''
     inherit buildPhase;
 
     installPhase = ''
-      target=$out/vim-plugins/$path
-      ensureDir $out/vim-plugins
+      target=$out/share/vim-plugins/${path}
+      ensureDir $out/share/vim-plugins
       cp -r . $target
       ${vimHelpTags}
       vimHelpTags $target
@@ -114,14 +114,14 @@ in rec
       rev = "abfc3ee36adab11c0c0b9d086a164a69006fec79";
       sha256 = "1d25dp5kgqickl06hqvx4j3z51zblhsn3q3by2hayyj3g2zps4gm";
      };
- 
+
     name = "youcompleteme-git-abfc3ee";
     buildInputs = [ python cmake clang.clang ];
 
     configurePhase = ":";
 
     buildPhase = ''
-      target=$out/vim-plugins/YouCompleteMe
+      target=$out/share/vim-plugins/YouCompleteMe
       mkdir -p $target
       cp -a ./ $target
 
@@ -311,7 +311,7 @@ in rec
 
     preBuild = ''
       sed -ie '1 i\
-      set runtimepath+=${vimproc}/vim-plugins/vimproc\
+      set runtimepath+=${vimproc}/share/vim-plugins/vimproc\
       ' autoload/vimshell.vim
     '';