functionp (ANSI and GNU Common Lisp Document)

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#### 5.3.10 functionp [Function]

`functionp` object ⇒ generalized-boolean

#### Arguments and Values::

object—an object.

generalized-boolean—a generalized boolean.

#### Description::

Returns true if object is of type function; otherwise, returns false.

#### Examples::

     (functionp 'append) ⇒  false
     (functionp #'append) ⇒  true
     (functionp (symbol-function 'append)) ⇒  true
     (flet ((f () 1)) (functionp #'f)) ⇒  true
     (functionp (compile nil '(lambda () 259))) ⇒  true
     (functionp nil) ⇒  false
     (functionp 12) ⇒  false
     (functionp '(lambda (x) (* x x))) ⇒  false
     (functionp #'(lambda (x) (* x x))) ⇒  true

#### Notes::

     (functionp object) ≡ (typep object 'function)