lib.strings.intersperse -> lib.lists.intersperse.

`intersperse` is defined within `lib.strings` yet does not work for
strings, only lists. Furthermore, it only returns a list. There is no
sense in a function that only works with lists being in the strings
library.

lib/lists.nix

@@ -393,6 +393,23 @@ rec {
   reverseList = xs:
     let l = length xs; in genList (n: elemAt xs (l - n - 1)) l;
 
+  /* Place an element between each element of a list
+
+     Type: intersperse :: a -> [a] -> [a]
+
+     Example:
+       intersperse "/" ["usr" "local" "bin"]
+       => ["usr" "/" "local" "/" "bin"].
+  */
+  intersperse =
+    # Separator to add between elements
+    separator:
+    # Input list
+    list:
+    if list == [] || length list == 1
+    then list
+    else tail (lib.concatMap (x: [separator x]) list);
+
   /* Depth-First Search (DFS) for lists `list != []`.
 
      `before a b == true` means that `b` depends on `a` (there's an

lib/strings.nix

@@ -41,23 +41,6 @@ rec {
   */
   concatImapStrings = f: list: concatStrings (lib.imap1 f list);
 
-  /* Place an element between each element of a list
-
-     Type: intersperse :: a -> [a] -> [a]
-
-     Example:
-       intersperse "/" ["usr" "local" "bin"]
-       => ["usr" "/" "local" "/" "bin"].
-  */
-  intersperse =
-    # Separator to add between elements
-    separator:
-    # Input list
-    list:
-    if list == [] || length list == 1
-    then list
-    else tail (lib.concatMap (x: [separator x]) list);
-
   /* Concatenate a list of strings with a separator between each element
 
      Type: concatStringsSep :: string -> [string] -> string