我使用GNU/MIT计划:为什么+和*分别评估为0和1?
1 ]=> (+)
;Value: 0
1 ]=> (*)
;Value: 1
1 ]=> (-)
;The procedure #[arity-dispatched-procedure 2] has been called with 0 arguments; it requires at least 1 argument.
;To continue, call RESTART with an option number:
; (RESTART 1) => Return to read-eval-print level 1.
2 error> (/)
;The procedure #[arity-dispatched-procedure 3] has been called with 0 arguments; it requires at least 1 argument.
;To continue, call RESTART with an option number:
; (RESTART 2) => Return to read-eval-print level 2.
; (RESTART 1) => Return to read-eval-print level 1.
怎么来+
和*
都分别评估,以0和1。为什么评估-
和/
会引发错误?
这是计划定义的一部分还是在GNU/MIT计划中的实现细节?
https://en.wikipedia.org/wiki/Empty_product https://en.wikipedia.org/wiki/Empty_sum – Wes