[elephant-devel] Querying for objects on two slots

[Leslie P. Polzer]

On Mon, Jan 05, 2009 at 10:36:29PM -0800, Yarek Kowalik wrote:
> I've run into several situations where I want to query for objects that
> match values two or more slots.  I currently do something like this:
> 
> (defclass my-class ()
>   ((a :accessor slot-a)
>    (b :accessor slot-b
>       :index b))
>   (:documentation "my test class"))
> 
> (find-if (lambda (obj)
>            (equal (slot-a obj) val-a))
>          (elephant:get-instances-by-value 'my-class 'slot-b val-b))
> 
> 
> Is this a reasonable way of finding an object of type 'my-class that matches
> on values val-a and val-b for slots a and b?

Use MAP-CLASS, this will considerably speed up the query.