Pattern Matching in Ruby

Inspired by a discussion on the Italian Ruby mailing list, I decided to write (probably another) pattern matching implementation for ruby. In the short term I want to be able to define something like:

func :qsort, [] { [] } 
func :qsort do | list | 
    qsort( list.select {|a| a <  list[0]} )  + 
        list.select {|a| a == list[0]}    + 
        qsort( list.select {|a| a >  list[0]} ) 
end 

and if I find time it could become even some kind of "declarative like" unification algorithm... who knows. The point is I don't even know if I have enough time for the "toy" pattern matching.

[from the future: I did not find time!]