chickadee » prometheus » define-method

This is syntactic sugar for the often-used idiom to define a method slot, by sending a add-method-slot! message with a message name and a lambda form with self, resend and args formals, and a body.

Another common operation is to clone an object, and add a number of value and method slots:

(define o (*the-root-object* 'clone))
(o 'add-value-slot! 'constant 'set-constant! 5)
(o 'add-method-slot! 'add
   (lambda (self resend summand)
     (+ summand (self 'constant))))

This can be more succintly written as:

(define-object o (*the-root-object*)
  (constant set-constant! 5)
  ((add self resend summand)
   (+ summand (self 'constant)))