CLCS
Function

identity

identity objectobject

Arguments and Values

objectan object.

Description

Returns its argument object.

Examples

 (identity 101) ⇒  101
 (mapcan #'identity (list (list 1 2 3) '(4 5 6))) ⇒  (1 2 3 4 5 6)

Notes

identity is intended for use with functions that require a function as an argument.

(eql x (identity x)) returns true for all possible values of x, but (eq x (identity x)) might return false when x is a number or character.

identity could be defined by

(defun identity (x) x)