diff --git a/util/lib/puppet/parser/functions/is_array.rb b/util/lib/puppet/parser/functions/is_array.rb
new file mode 100644
index 0000000..7892b1d
--- /dev/null
+++ b/util/lib/puppet/parser/functions/is_array.rb
@@ -0,0 +1,8 @@
+module Puppet::Parser::Functions
+    newfunction(:is_array, :type => :rvalue) do |args|
+        if args.length != 1
+            raise Puppet::ParseError, ("is_array(): wrong number of arguments (#{args.length}; must be 2)")
+        end
+        args[0].is_a?(Array)
+    end
+end