Name

missing-value

Usage

constant

Syntax

missing-value

Description

Alternative for null default arguments.

user > (defmacro some-return (&optional (a missing-value))
           (if (missing-value? a)
                 `(return)
               `(return ,a)))
it: some-return
user > (macroexpand '(some-return))
it: (return null)
user > (macroexpand '(some-return null))
it: (return null)

See also

missing-value?