copy-pprint-dispatch set-pprint-dispatch pprint-dispatch

(copy-pprint-dispatch &optional table) -- (set-pprint-dispatch type-specifier function &optional priority table) -- (pprint-dispatch object &optional table)

The pretty-print dispatch table: a set of (type-specifier function priority) entries saying how to print a value of a given type. copy-pprint-dispatch answers a fresh copy of *print-pprint-dispatch* (or of the empty initial table when given nil), set-pprint-dispatch adds an entry -- or removes one when function is nil -- and pprint-dispatch answers the highest-priority entry function matching an object, plus a second value saying whether one was found. An entry function is called as (funcall function stream object).

The ordinary printing operators (print, princ, prin1, ~A, ~S) do not consult the table: an entry takes effect where the program calls the entry function itself.