Binding Lists

A binding is a correspondence of a name and a value.

A set of bindings is represented as a list, called an association list, or alist for short. A new binding can be added by:
(push (list name value ) binding-list )

A name can be looked up using assoc:
(assoc name binding-list )

(assoc '?y '((?x 3) (?y 4) (?z 5)))
   =  (?Y 4)

(second (assoc '?y '((?x 3) (?y 4) (?z 5))))
   =  4