来自 https://github.com/tonsky/datascript
(->
(d/q '[:find ?color (max ?amount ?x) (min ?amount ?x)
:in [[?color ?x]] ?amount]
[[:red 10] [:red 20] [:red 30] [:red 40] [:red 50]
[:blue 7] [:blue 8]]
4)
pr-str
js/console.log)
;;; ([:red [20 30 40 50] [10 20 30 40]] [:blue [7 8] [7 8]])
(->
(d/q '[:find ?color (max ?amount ?x) (min ?amount ?x)
:in [[?color ?x]] ?amount]
[[:red 10] [:red 20] [:red 30] [:red 40] [:red 50]
[:blue 7] [:blue 8]]
3)
pr-str
js/console.log)
;;; ([:red [30 40 50] [10 20 30]] [:blue [7 8] [7 8]])
(->
(d/q '[:find ?color (max ?amount ?x) (min ?amount ?x)
:in [[?color ?x]] ?amount]
[[:red 10] [:red 20] [:red 30] [:red 40] [:red 50]
[:blue 7] [:blue 8]]
2)
pr-str
js/console.log)
;;; ([:red [40 50] [10 20]] [:blue [7 8] [7 8]])
所以，这不是关于它在做什么的问题，而是关于它如何（或至少为什么）这样做的问题。max 和 min 是分别返回其后续整数的最大值或最小值的函数。如何?amount考虑限制聚合计数？为什么这些东西总是聚集在一起？代码如何运行以使其聚合。我真的不明白这段代码是如何产生结果的。