How to get instance from instance-name ?

[Christine DG]

I would like to embedd an instance [a] of class A in an instance [b] of Class B and access [a] from [b]. But I haven't find a way !
(make-instance) returns the instance-name ; how can I reach the instance itself ?

CLIPS> (defclass A (is-a USER) (role concrete))
CLIPS> (defclass B (is-a USER) (role concrete)  
    (slot A
        (type INSTANCE)
        (allowed-classes A)
        (default ?NONE)
    ) 
)
CLIPS> (make-instance of B (A (make-instance of A)))
CLIPS> (instances)
[initial-object] of INITIAL-OBJECT
[gen1] of B
[gen2] of A
For a total of 3 instances.
CLIPS> (send [gen1] print)
[gen1] of B
(A [gen2])
CLIPS> (send [gen1]:A print)
[MSGFUN1] No applicable primary message-handlers found for print.
FALSE
CLIPS> (send [gen2] print)
[gen2] of A
CLIPS> (class [gen1])
B
CLIPS> (class [gen1]:A)
SYMBOL
CLIPS> 

[Gary Riley]

Short hand slot references work with variables in appropriate situations (such as ?self:A in a message-handler). The syntax you've used to retrieve a slot from an instance name, [gen1]:A, is not supported. Use (send [gen1] get-A) instead. If you do want to convert an instance name to an instance address, use the instance-address function.

CLIPS> (defclass A (is-a USER) (role concrete))
CLIPS> 
(defclass B (is-a USER) (role concrete)  
    (slot A
        (type INSTANCE)
        (allowed-classes A)
        (default ?NONE)))
CLIPS> (make-instance of B (A (make-instance of A)))
[gen1]
CLIPS> (instances)
[initial-object] of INITIAL-OBJECT
[gen1] of B
[gen2] of A
For a total of 3 instances.
CLIPS> (send [gen1] print)
[gen1] of B
(A [gen2])
CLIPS> (send (send [gen1] get-A) print)
[gen2] of A
CLIPS> (send [gen2] print)
[gen2] of A
CLIPS> (class [gen1])
B
CLIPS> (class (send [gen1] get-A))
A
CLIPS> (instance-address [gen2])
<Instance-gen2>
CLIPS> (instance-address [gen1])
<Instance-gen1>
CLIPS> 

[Christine DG]

Thank you Gary,

I had seen this syntax in examples not in the reference manual.
I understand that it is better to avoid it!