An association list, abbreviated alist, is an association represented as a sequence where all elements are key/value pairs. The sequence mixin is an instance of the assoc mixin, hence all sequences support the Associative mapping protocol in this way.
While not an association list, note that f also implements the associative mapping protocol in a trivial way; it is an immutable assoc with no entries.
An alist is slower to search than a hashtable for a large set of associations. The main advantage of an association list is that the elements are ordered; also sometimes it is more convenient to construct an association list with sequence words than to construct a hashtable with association words. Much of the time, hashtables are more appropriate. See Hashtables.
There is no special syntax for literal alists since they are just sequences; in practice, literals look like so: