( b i n d i n g - v a l (get-binding var bindings)))

(defun extend- bi ndi ngs (var val bindings

"Add a (var . value) pair t o a binding l i s t ."

(cons (make-binding var val)

;; Once we add a "r e a l" binding,

;; we can get r i d of the dummy no-bindings

( i f (eq bindings no-bindings)

ni 1 bi ndi ngs

(defun match-variable (var input bindings)