typep object type-specifier &optional environment ⇒ generalized-boolean
| object | an object. |
| type-specifier | any type specifier except
values, or a type specifier list whose first element is either function or values. |
| environment | an environment object. The default is nil, denoting the null lexical environment and the and current global environment. |
| generalized-boolean | a generalized boolean. |
Returns true if object is of the type specified by type-specifier; otherwise, returns false.
A type-specifier of the form (satisfies fn)
is handled by applying the function fn to object.
(typep object '(array type-specifier)),
where type-specifier is not *,
returns true if and only if object is an array
that could be the result
of supplying type-specifier
as the :element-type argument to make-array.
(array *) refers to all arrays
regardless of element type, while (array type-specifier)
refers only to those arrays
that can result from giving type-specifier as the
:element-type argument to make-array.
A similar interpretation applies to (simple-array type-specifier)
and (vector type-specifier).
See Array Upgrading.
(typep object '(complex type-specifier))
returns true for all complex numbers that can result from
giving numbers of type type-specifier
to the function complex, plus all other complex numbers
of the same specialized representation.
Both the real and the imaginary parts of any such
complex number must satisfy:
(typep realpart 'type-specifier)
(typep imagpart 'type-specifier)
See the function upgraded-complex-part-type.
(typep 12 'integer) ⇒ true
(typep (1+ most-positive-fixnum) 'fixnum) ⇒ false
(typep nil t) ⇒ true
(typep nil nil) ⇒ false
(typep 1 '(mod 2)) ⇒ true
(typep #c(1 1) '(complex (eql 1))) ⇒ true
;; To understand this next example, you might need to refer to
;; Rule of Canonical Representation for Complex Rationals.
(typep #c(0 0) '(complex (eql 0))) ⇒ false
Let A_x and A_y be two type specifiers that
denote different types, but for which
(upgraded-array-element-type 'A_x)
and
(upgraded-array-element-type 'A_y)
denote the same type. Notice that
(typep (make-array 0 :element-type 'A_x) '(array A_x)) ⇒ true
(typep (make-array 0 :element-type 'A_y) '(array A_y)) ⇒ true
(typep (make-array 0 :element-type 'A_x) '(array A_y)) ⇒ true
(typep (make-array 0 :element-type 'A_y) '(array A_x)) ⇒ true
An error of type error is signaled if type-specifier is values,
or a type specifier list whose first element is either
function or values.
The consequences are undefined if the type-specifier is not a type specifier.
Implementations are encouraged to recognize and optimize the case of
(typep x (the class y)),
since it does not involve any need for expansion
of deftype information at runtime.