take-while 和 java-time/iterate 创造奇怪的结果

Question

我正在使用 clojure.java-time 版本 0.3.2，我有一个 TemporalAdjuster 定义如下：

(def next-pay-day
  (reify java.time.temporal.TemporalAdjuster
    (adjustInto [this temporal]
      (let [local-date (java.time.LocalDate/from temporal)
            day-of-month (j/as local-date :day-of-month)
            last-day-of-month (j/as (j/adjust local-date :last-day-of-month) :day-of-month)]
        (cond 
          (= day-of-month last-day-of-month) 
          (j/plus local-date (j/days 14))

          (< day-of-month 14) 
          (j/plus local-date (j/days (- 14 day-of-month)))

          :else 
          (j/adjust local-date :last-day-of-month))))))

它的工作原理是这样的：

=> (require '[pto-calculator.logic.pay-periods :as p])
nil
=> (require '[java-time :as j])
nil
=> (take 4 (j/iterate j/adjust (j/local-date 2019 3 3) p/next-pay-day))
(#object[java.time.LocalDate 0x74e53020 "2019-03-03"] #object[java.time.LocalDate 0x49980a "2019-03-14"] #object[java.time.LocalDate 0x2e332a36 "2019-03-31"] #object[java.time.LocalDate 0x5e7aaec6 "2019-04-14"])

我正在尝试生成从今天到 t 之间的发薪日列表，其中 t 是 LocalDate 以后的某个时间。我有这个，但问题是它似乎适用于某些日期（4 月 15 日）：

=> (take-while #(= 1 (compare (j/local-date 2019 4 15) %)) (j/iterate j/adjust (j/local-date 2019 3 3) p/next-pay-period))
(#object[java.time.LocalDate 0xc994eb6 "2019-03-03"] #object[java.time.LocalDate 0x3ec8e48 "2019-03-14"] #object[java.time.LocalDate 0x1bddd9d5 "2019-03-31"] #object[java.time.LocalDate 0x133ed931 "2019-04-14"])
; Last date is 2019-04-14 (expected)

但不适合其他人（4 月 18 日）：

=> (take-while #(= 1 (compare (j/local-date 2019 4 18) %)) (j/iterate j/adjust (j/local-date 2019 3 3) p/next-pay-period))
(#object[java.time.LocalDate 0x7f0ac64b "2019-03-03"] #object[java.time.LocalDate 0x1f1d3684 "2019-03-14"] #object[java.time.LocalDate 0x70415bc3 "2019-03-31"])
; Last date is 2019-03-31 (unexpected, should be 2019-04-14)

为什么 4 月 18 日的操作中断，但 4 月 15 日的操作正常？

Answer 1

compare 并不总是 return 1、0 或 -1。所以，而不是：

#(= 1 (compare (j/local-date 2019 4 15) %))

尝试：

#(pos? (compare (j/local-date 2019 4 15) %))

take-while 和 java-time/iterate 创造奇怪的结果

take-while and java-time/iterate creating odd results

clojure

java-time