"GOF patterns are indeed language agnostic"

I enjoyed this series of articles published some years ago making the case that many of the useful design patterns are built into Perl already:

http://www.perl.com/pub/2003/06/13/design1.html

http://www.perl.com/pub/2003/08/07/design2.html

http://www.perl.com/pub/2003/08/15/design3.html

The take-away point being "If a pattern is really valuable, then it should be part of the core language". Perl, of course, has very strong functional features, as described in Higher Order Perl:

http://hop.perl.plover.com/