Larry O'Brien recently interviewed three of the Gang of Four about their seminal work on patterns. Larry teased the interview's readers for awhile, but he eventually asked the pressing question that most language designers ask and debate about patterns ;) Here it is:
Larry: GoF came out relatively early in the ascent of OOP as the mainstream paradigm and, for better or worse, "patterns" seem to be associated with OO approaches. You even hear functional and dynamic advocates boasting that their languages "don't need" patterns. How do you respond to that?
Erich: Just as an aside, it is also easy to forget that we wrote design patterns before there was Java or C#.
Ralph: Some of those languages don't need some of the patterns in Design Patterns because their languages provide alternative ways of solving the problems. Our patterns are for languages between C++ and Smalltalk, which includes just about everything called "object-oriented," but they certainly are not for every programming language. I don't think anybody actually says that programmers in other languages don't need patterns; they just have a different set of patterns.
Erich: Design patterns eventually emerge for any language. Design déjà-vu is language neutral. While these experiences are not always captured as patterns, they do exist. The design principles for Erlang come to mind.
Larry: Where would a person go to learn about patterns for dynamic and functional languages? Who's making good contributions?
Ralph: If by "dynamic" you mean dynamic object-oriented languages like Smalltalk, Ruby or Python, then our patterns are applicable. Functional languages require different patterns, but I don't know who is working on them.
Note: At the end of the interview, Erich says that they tried refactoring the patterns into new categories in 2005. The draft breakdown he provides (accidentally???) takes out Memento, Chain of Responsibility, Bridge, Adapter, and Observer.
As I said above these are just notes in a draft state. Doing a refactoring without test cases is always dangerous...
UPDATE: The Gang of Four have an accompanying article for the interview that they wrote as a group. See A Look Back: Why We Wrote Design Patterns: Elements of Reusable Object-Oriented Software.