This guarantees that there will never be two entries associated with the same type specifier in a given pprint dispatch table . Equality of type specifiers is tested by equal . The function should pretty print the object to the stream . The function can assume that object satisfies the type given by type-specifier . Any values returned by the function are ignored.
Priority is a priority to resolve conflicts when an object matches more than one entry.
It is permissible for function to be nil . The cdr-type can be omitted in which case it defaults to t .