diff --git a/lib/default.nix b/lib/default.nix
index f2cd421b..95600648 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -1,21 +1,42 @@
-# All of the custom functions suitable for all environments.
+# The entrypoint for our custom library set.
 { lib }:
 
-rec {
-  /* Count the attributes with the given predicate.
+lib.makeExtensible
+  (self:
+    rec {
+      /* Count the attributes with the given predicate.
 
-     Examples:
-       countAttrs (name: value: value) { d = true; f = true; a = false; }
-       => 2
+         Examples:
+           countAttrs (name: value: value) { d = true; f = true; a = false; }
+           => 2
 
-       countAttrs (name: value: value.enable) { d = { enable = true; }; f = { enable = false; package = [ ]; }; }
-       => 1
-  */
-  countAttrs = pred: attrs:
-    lib.count (attr: pred attr.name attr.value)
-      (lib.mapAttrsToList lib.nameValuePair attrs);
+           countAttrs (name: value: value.enable) { d = { enable = true; }; f = { enable = false; package = [ ]; }; }
+           => 1
+      */
+      countAttrs = pred: attrs:
+        lib.count (attr: pred attr.name attr.value)
+          (lib.mapAttrsToList lib.nameValuePair attrs);
 
-  getConfig = type: config: ../configs/${type}/${config};
+      /* Returns the file path of the given config of the given environment.
 
-  getUser = type: user: ../configs/${type}/_users/${user};
-}
+         Type: getConfig :: String -> String -> Path
+
+         Example:
+           getConfig "home-manager" "foo-dogsquared"
+           => ../configs/home-manager/foo-dogsquared
+      */
+      getConfig = type: config: ../configs/${type}/${config};
+
+
+      /* Returns the file path of the given user subpart of the given
+         environment. Only certain environments such as NixOS have this type of
+         setup.
+
+         Type: getConfig :: String -> String -> Path
+
+         Example:
+           getUser "nixos" "foo-dogsquared"
+           => ../configs/nixos/_users/foo-dogsquared
+      */
+      getUser = type: user: ../configs/${type}/_users/${user};
+    })