🚀 go-pugleaf

In article <BxHA1I.G6D@world.std.com>, jbk@world.std.com (Jeffrey B Kane) writes:

|> ... I should define a constructor
|> function, then check if various key words have been defined, i.e.
|> 
|> (defclass test-class ()
|>   ((slot-1	:initarg :slot-1
|> 		:accessor slot-1)
|>    (slot-2	:initarg :slot-2
|> 		:accessor slot-2)))
|> 
|> (defun make-test-class (&key (slot-1 3) slot-2)
|>   (unless (boundp slot2)
|>     (setf slot-2 slot-1))
|>   (make-instance 'test-class :slot-1 slot-1 :slot-2 slot-2))
|> 
|> Other than defining a keyword with some kind of a value to flag it
|> hasn't been used, how can you test if it was used similar to slot-boundp
|> for slots?

The lambda list of the function supports this kind of test. See page 76 of CLtL2.

(defun make-test-class (&key (slot-1 3) (slot-2 nil existp))
   (unless existp
     (setq slot-2 slot-1))
   (make-instance 'test-class :slot-1 slot-1 :slot-2 slot-2))
..................................................
                                  Len Charest, Jr.
                 JPL Artificial Intelligence Group
                          charest@aig.jpl.nasa.gov