Now let's use this function to describe the floor:
      (defun describe-floor (loc objs obj-loc)
        (apply #'append (mapcar (lambda (x)
                                  `(you see a ,x on the floor -))
                                (remove-if-not (lambda (x)
                                                 (is-at x loc obj-loc))
                                               objs))))
This function has a couple of new things: First of all, it has anonymous functions (`lambda` is just a fancy word for this). That first lambda form is just the same as defining a helper function `(defun blabla (x) `(you see a ,x on the floor.))` and then sending `#'blabla` to the `mapcar` function. The `remove-if-not` function removes any objects from the list that are not at the current location before passing the list on to `mapcar` to build pretty sentences. Let's try this new function:
      (describe-floor 'living-room objects object-locations)
      ==> (you see a whiskey-bottle on the floor - you see a bucket
           on the floor -)
Now we can tie all these descriptor functions into a single, easy command called `look` that uses the global variables (therefore this function is not in the Functional Programming style) to feed all the descriptor functions and describes everything:
      (defun look ()
        (append (describe-location location map)
                (describe-paths location map)
                (describe-floor location objects object-locations)))
<< begin < previous - next > end >>