Apropos

+, ++, +++Variable

    Value Type

    an object.

    Initial Value

    implementation-dependent.

    Description

    The variables +, ++, and +++ are maintained by the Lisp read-eval-print loop to save forms that were recently evaluated.

    The value of + is the last form that was evaluated, the value of ++ is the previous value of +, and the value of +++ is the previous value of ++.

    Examples
    (+ 0 1)  1 
    (- 4 2)  2 
    (/ 9 3)  3 
    (list + ++ +++)  ((/ 9 3) (- 4 2) (+ 0 1)) 
    (setq a 1 b 2 c 3 d (list a b c))  (1 2 3) 
    (setq a 4 b 5 c 6 d (list a b c))  (4 5 6) 
    (list a b c)  (4 5 6) 
    (eval +++)  (1 2 3) 
    #.`(,@++ d)  (1 2 3 (1 2 3))
    Affected By

    Lisp read-eval-print loop.

    See Also

    - (variable), * (variable), / (variable), Section 25.1.1 (Top level loop)