Page 239	Table of Contents	Index	Page 241
	Chapters
	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 A, B, C, D, E

---

CHAPTER 23. PRESENTATION TYPES


23.8.7 "Meta" Presentation Types

=> or &rest types [Presentation Type]
The type that is used to specify one of several types, for example, (or (member :all :none)
integer). The elements of types can be presentation type abbreviations. accept returns one of
the possible types as its second value, not the original or presentation type specifier.

=> and &rest types [Presentation Type]
The type that is used for "multiple inheritance". and is frequently used in conjunction with
satisfies, for example, (and integer (satisfies oddp)). The elements of types can be
presentation type abbreviations.

The and type has special syntax that supports the two "predicates", satisfies and not.
satisfies and not cannot stand alone as presentation types and cannot be first in types. not
can surround either satisfies or a presentation type.

The first type in types is the type whose methods will be used during calls to accept and
present.

23.8.8 Compound Presentation Types

=> token-or-type tokens type [Presentation Type Abbreviation]
A compound type that is used to select one of a set of special tokens, or an object of type type.
tokens is anything that can be used as the sequence parameter to member-alist; typically it is
a list of symbols.

=> null-or-type type [Presentation Type Abbreviation]
A compound type that is used to select nil, whose printed representation is the special token
"None", or an object of type type.

=> type-or-string type [Presentation Type Abbreviation]
A compound type that is used to select an object of type type or an arbitrary string, for example,
(type-or-string integer). Any input that accept cannot parse as the representation of an
object of type type is returned as a string.

23.8.9 Lisp Expression Presentation Types

=> expression [Presentation Type]
The type used to represent any Lisp object. The standard print and read functions produce
and accept the textual view of this type.

---

Page 239	Table of Contents	Index	Page 241
	Chapters
	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 A, B, C, D, E