Land of Lisp

Picking Up Objects

Next, let’s create a command to pick up objects in our world. To do so, we modify the variable *object-locations* that we’re using to track the location of objects:

(defun pickup (object)
  (cond ((member object
                 (objects-at *location* *objects* *object-locations*))
         (push (list object 'body) *object-locations*)
           `(you are now carrying the ,object))
          (t '(you cannot get that.))))

The pickup function uses the member function to see if ...