Add filterListByPackageName to helper function

* Add filterListByPackageName to helper functions
  * This function makes it easier to check if a list of packages
    contains a package with a name that contains a specific string

overlays/libs/helpers.nix

@@ -1,6 +1,6 @@
 { lib, ... }:
 with lib;
-{
+rec {
 
   # TODO: Improve error-handling/provide error messages that specify the expected inputs for each function, etc
 
@@ -12,4 +12,10 @@ with lib;
 
   # are we running on a NixOS system?
   isNixOS = builtins.readDir /etc ? NIXOS;
+
+  # find the packages in the given <list> that contain <query> 
+  filterListByPackageName = list: query: lib.lists.filter (x: lib.strings.hasInfix query (lib.strings.getName x)) list;
+
+  # find the packages in systemPackages that contain <query>
+  #filterSystemPackagesByPackageName = query: filterListByPackageName query environment.systemPackages;
 }