Page 216	Table of Contents	Index	Page 218
	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

=> with-presentation-type-options (type-name type) &body body [Macro]
Variables with the same name as each option in the definition of the presentation type are bound
to the option values in type, if present, or else to the defaults specified in the definition of the
presentation type. The forms in body are executed in the scope of these variables and the values
of the last form are returned.

The value of the form type must be a presentation type specifier whose name is type-name. The
type-name and type arguments are not evaluated. body may have zero or more declarations as
its first forms.

=> presentation-type-specifier-p object [Function]
Returns true if object is a valid presentation type specifier, otherwise returns false.

=> presentation-typep object type [Function]
Returns true if object is of the presentation type specified by the presentation type specifier type,
otherwise returns false.

type may not be a presentation type abbreviation.

This is analogous to the Common Lisp typep function.

=> presentation-type-of object [Function]
Returns a presentation type of which object is a member. presentation-type-of returns the
most specific presentation type that can be conveniently computed and is likely to be useful to
the programmer. This is often the class name of the clas of the object.

If presentation-type-of cannot determine the presentation type of the object, it may return
either expression or t.

This is analogous to the Common Lisp typep function.

=> presentation-subtypep type putative-supertype [Function]
Answers the question "is the type specified by the presentation type specifier type a subtype
of the type specified by the presentation type specifier putative-supertype?". presentation- subtypepreturns two values, subtypep and known-p. When known-p is true, subtypep can be
either true (meaning that type is definitely a subtype of putative-supertype) or false (meaning
that type is definitely not a subtype of putative-supertype). When known-p is false, then subtypep
must also be false; this means that the answer cannot reliably be determined.

type may not be a presentation type abbreviation.

This is analogous to the Common Lisp subtypep function.

=> map-over-presentation-type-supertypes function type [Function]
Calls the function function on the presentation type specifier type and each of its supertypes.

Page 216	Table of Contents	Index	Page 218
	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