add split-filename

split-filename.nix

@@ -0,0 +1,7 @@
+with builtins;
+
+f:
+  let mr = match "(.*)[.]([^.]*)|(.*)" f;
+  in if head mr == null
+    then { name = (elemAt mr 2); extension = null; }
+    else { name = (elemAt mr 0); extension = (elemAt mr 1); }