GOOPS with variable number of arguments

[Jan Wedekind <jan@wedesoft.de>]

Hi,
I am trying to implement n-ary operations for different types of objects.
When specialising "+" for two arguments, it will automatically work on 
more arguments.

     (use-modules (oop goops) (srfi srfi-1))
     (define-generic +)
     (define-method (+ (a <string>) (b <string>)) (string-append a b))
     (+ "a" "b" "c")
     ; "abc"

However I have trouble figuring out a method definition for test which 
would result in the same behaviour.

     (define (test . args) ...)
     (define-generic test)
     (define-method (test (a <string>) (b <string>)) (string-append a b))
     (test "a" "b" "c")
     ; "abc"

Please let me know if there is a solution.