• Cast

(define-polymorphic-function cast (object type))

Casts an object to a specified type. Type should always be a symbol. Non-mutating, i.e. always returns a new object.

• Copy

(define-polymorphic-function deep-copy (object))
(define-polymorphic-function shallow-copy (object))

Deep-copy copies the object recursively, while shallow-copy only copies the topmost container, leaving the insides as references. Returns object of precisely the same type as the original one.