Function listp

Syntax:

Arguments and Values:

object—an object.

generalized-boolean—a generalized boolean.

Description:

6.2.2 10Returns true if object is of type list; otherwise, returns false.

Examples:

 (listp nil) → true
 (listp (cons 1 2)) → true
 (listp (make-array 6)) → false
 (listp t) → false

Side Effects:

None.

Affected By:

None.

Exceptional Situations:

None.

See Also:

consp

Notes:

This is implied by type list, but still worth saying. -kmp

If object is a cons, listp does not check whether object is a proper list; it returns true for any kind of list.

 (listp object) ≡ (typep object 'list) ≡ (typep object '(or cons null))