diff --git a/modules/launchd/default.nix b/modules/launchd/default.nix
index dccddd0..8ff6933 100644
--- a/modules/launchd/default.nix
+++ b/modules/launchd/default.nix
@@ -35,56 +35,7 @@ let
       config = {
         serviceConfig.Label = mkDefault "org.nixos.${name}";
 
-        plist = pkgs.writeText "${config.serviceConfig.Label}.plist" (''
-          <?xml version="1.0" encoding="UTF-8"?>
-          <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-          <plist version="1.0">
-            <dict>
-        '' + xmlMapAttr xmlString "Label" config.serviceConfig.Label
-           + xmlMapAttr xmlBool "Disabled" config.serviceConfig.Disabled
-           + xmlMapAttr xmlString "UserName" config.serviceConfig.UserName
-           + xmlMapAttr xmlString "GroupName" config.serviceConfig.GroupName
-           + xmlMapAttr (xmlMapAttrs xmlBool) "inetdCompatibility" config.serviceConfig.inetdCompatibility
-           + xmlMapAttr (xmlMap xmlString) "LimitLoadToHosts" config.serviceConfig.LimitLoadToHosts
-           + xmlMapAttr (xmlMap xmlString) "LimitLoadFromHosts" config.serviceConfig.LimitLoadFromHosts
-           + xmlMapAttr xmlString "LimitLoadToSessionType" config.serviceConfig.LimitLoadToSessionType
-           + xmlMapAttr xmlString "Program" config.serviceConfig.Program
-           + xmlMapAttr (xmlMap xmlString) "ProgramArguments" config.serviceConfig.ProgramArguments
-           + xmlMapAttr xmlBool "EnableGlobbing" config.serviceConfig.EnableGlobbing
-           + xmlMapAttr xmlBool "EnableTransactions" config.serviceConfig.EnableTransactions
-           + xmlMapAttr xmlBool "OnDemand" config.serviceConfig.OnDemand
-           + xmlMapAttr xmlBool "KeepAlive" config.serviceConfig.KeepAlive
-           + xmlMapAttr xmlBool "RunAtLoad" config.serviceConfig.RunAtLoad
-           + xmlMapAttr xmlString "RootDirectory" config.serviceConfig.RootDirectory
-           + xmlMapAttr xmlString "WorkingDirectory" config.serviceConfig.WorkingDirectory
-           + xmlMapAttr (xmlMapAttrs xmlString) "EnvironmentVariables" config.serviceConfig.EnvironmentVariables
-           + xmlMapAttr xmlInt "Umask" config.serviceConfig.Umask
-           + xmlMapAttr xmlInt "TimeOut" config.serviceConfig.TimeOut
-           + xmlMapAttr xmlInt "ExitTimeOut" config.serviceConfig.ExitTimeOut
-           + xmlMapAttr xmlInt "ThrottleInterval" config.serviceConfig.ThrottleInterval
-           + xmlMapAttr xmlBool "InitGroups" config.serviceConfig.InitGroups
-           + xmlMapAttr (xmlMap xmlString) "WatchPaths" config.serviceConfig.WatchPaths
-           + xmlMapAttr (xmlMap xmlString) "QueueDirectories" config.serviceConfig.QueueDirectories
-           + xmlMapAttr xmlBool "StartOnMount" config.serviceConfig.StartOnMount
-           + xmlMapAttr xmlInt "StartInterval" config.serviceConfig.StartInterval
-           + xmlMapAttr (xmlMapAttrs xmlInt) "StartCalendarInterval" config.serviceConfig.StartCalendarInterval
-           + xmlMapAttr xmlString "StandardInPath" config.serviceConfig.StandardInPath
-           + xmlMapAttr xmlString "StandardOutPath" config.serviceConfig.StandardOutPath
-           + xmlMapAttr xmlString "StandardErrorPath" config.serviceConfig.StandardErrorPath
-           + xmlMapAttr xmlBool "Debug" config.serviceConfig.Debug
-           + xmlMapAttr xmlBool "WaitForDebugger" config.serviceConfig.WaitForDebugger
-           + xmlMapAttr (xmlMapAttrs xmlInt) "SoftResourceLimits" config.serviceConfig.SoftResourceLimits
-           + xmlMapAttr (xmlMapAttrs xmlInt) "HardResourceLimits" config.serviceConfig.HardResourceLimits
-           + xmlMapAttr xmlInt "Nice" config.serviceConfig.Nice
-           + xmlMapAttr xmlString "ProcessType" config.serviceConfig.ProcessType
-           + xmlMapAttr xmlBool "AbandonProcessGroup" config.serviceConfig.AbandonProcessGroup
-           + xmlMapAttr xmlBool "LowPriorityIO" config.serviceConfig.LowPriorityIO
-           + xmlMapAttr xmlBool "LaunchOnlyOnce" config.serviceConfig.LaunchOnlyOnce
-           + xmlMapAttr (xmlMapAttrs xmlBool) "MachServices" config.serviceConfig.MachServices
-           + ''
-            </dict>
-          </plist>
-        '');
+        plist = pkgs.writeText "${config.serviceConfig.Label}.plist" (toPLIST config.serviceConfig);
       };
     };
 
diff --git a/modules/launchd/lib.nix b/modules/launchd/lib.nix
index 483a0d1..65fc036 100644
--- a/modules/launchd/lib.nix
+++ b/modules/launchd/lib.nix
@@ -2,27 +2,56 @@
 
 with lib;
 
+let
+
+  attrFilter = name: value: name != "_module" && value != null;
+
+in
+
 rec {
 
-  xmlMap = f: xs: ''
-    <array>
-    ${concatMapStringsSep "\n" f xs}
-    </array>
-  '';
+  toPLIST = x: ''
+    <?xml version="1.0" encoding="UTF-8"?>
+    <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+    <plist version="1.0">
+  '' + pprExpr "" x
+     + "\n</plist>";
 
-  xmlMapAttrs = f: attr: ''
-    <dict>
-    ${concatStringsSep "\n" (mapAttrsFlatten (xmlMapAttr f) attr)}
-    </dict>
-  '';
+  pprExpr = ind: x:
+    if isNull x then "" else
+    if isBool x then pprBool ind x else
+    if isInt x then pprInt ind x else
+    if isString x then pprStr ind x else
+    if isList x then pprList ind x else
+    if isAttrs x then pprAttrs ind x else
+    throw "invalid plist type";
 
-  xmlMapAttr = f: n: v: optionalString (v != null) ''
-    <key>${n}</key>
-    ${f v}
-  '';
+  pprLiteral = ind: x: ind + x;
 
-  xmlBool = x: if x then "<true/>" else "<false/>";
-  xmlInt = x: "<integer>${toString x}</integer>";
-  xmlString = x: "<string>${x}</string>";
+  pprBool = ind: x: pprLiteral ind  (if x then "<true/>" else "<false/>");
+  pprInt = ind: x: pprLiteral ind "<integer>${toString x}</integer>";
+  pprStr = ind: x: pprLiteral ind "<string>${x}</string>";
+  pprKey = ind: x: pprLiteral ind "<key>${x}</key>";
+
+  pprIndent = ind: (pprExpr "\t${ind}");
+
+  pprItem = ind: concatMapStringsSep "\n" (pprIndent ind);
+
+  pprList = ind: x: concatStringsSep "\n" [
+    (pprLiteral ind "<array>")
+    (pprItem ind x)
+    (pprLiteral ind "</array>")
+  ];
+
+  pprAttrs = ind: x: concatStringsSep "\n" [
+    (pprLiteral ind "<dict>")
+    (pprAttr ind x)
+    (pprLiteral ind "</dict>")
+  ];
+
+  pprAttr = ind: x: concatStringsSep "\n" (flatten (mapAttrsToList (name: value: optional (attrFilter name value) [
+    (pprKey "\t${ind}" name)
+    (pprExpr "\t${ind}" value)
+  ]) x));
 
 }