print-unreadable-object

(print-unreadable-object (object stream &key type identity) body...)

Writes #<...> around the body's output to stream and returns nil. A true :type prints the type-of designator first, followed by a space when a body follows it; :identity is accepted but prints no address -- there is no object-identity token in the value model, and a per-backend one would make the same program print differently on each backend. The usual body of a print-object method.

The type designator is written like any symbol, so *print-escape* decides whether its package qualifier appears: under prin1/~S a type defined in another package prints as PKG:NAME, under princ/~A as just NAME. The two agree for a type whose name needs no qualifier.