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Merged
hellerve merged 1 commit into from
May 29, 2026
Merged

Add diff, add-months, and add-years to Datetime #7

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180 changes: 179 additions & 1 deletion test/time.carp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -618,4 +618,182 @@
(Maybe.Nothing)
(Maybe.Nothing))
-3661))
"subtract 3661 seconds (1h1m1s) from 00:00:00"))
"subtract 3661 seconds (1h1m1s) from 00:00:00")

; --- Datetime.diff ---
(assert-equal test
0
(Datetime.diff &(Datetime.date 2024 3 15) &(Datetime.date 2024 3 15))
"diff: same date is 0")
(assert-equal test
86400
(Datetime.diff &(Datetime.date 2024 3 16) &(Datetime.date 2024 3 15))
"diff: one day apart is 86400")
(assert-equal test
-86400
(Datetime.diff &(Datetime.date 2024 3 15) &(Datetime.date 2024 3 16))
"diff: reversed order is negative")
(assert-equal test
3600
(Datetime.diff
&(Datetime.init 2024
3
15
(Maybe.Just 1)
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing))
&(Datetime.init 2024
3
15
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing)))
"diff: one hour apart is 3600")
(assert-equal test
90061
(Datetime.diff
&(Datetime.init 2024
3
16
(Maybe.Just 1)
(Maybe.Just 1)
(Maybe.Just 1)
(Maybe.Nothing)
(Maybe.Nothing))
&(Datetime.init 2024
3
15
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing)))
"diff: 1 day 1 hour 1 minute 1 second = 90061")
(assert-equal test
(* 365 86400)
(Datetime.diff &(Datetime.date 2023 1 1) &(Datetime.date 2022 1 1))
"diff: non-leap year is 365 days")
(assert-equal test
(* 366 86400)
(Datetime.diff &(Datetime.date 2025 1 1) &(Datetime.date 2024 1 1))
"diff: leap year 2024 has 366 days")

; --- Datetime.add-months ---
(assert-equal test
&(Datetime.date 2024 2 15)
&(Datetime.add-months &(Datetime.date 2024 1 15) 1)
"add-months: Jan to Feb")
(assert-equal test
&(Datetime.date 2024 2 29)
&(Datetime.add-months &(Datetime.date 2024 1 31) 1)
"add-months: Jan 31 to Feb 29 (leap year clamp)")
(assert-equal test
&(Datetime.date 2023 2 28)
&(Datetime.add-months &(Datetime.date 2023 1 31) 1)
"add-months: Jan 31 to Feb 28 (non-leap year clamp)")
(assert-equal test
&(Datetime.date 2024 4 30)
&(Datetime.add-months &(Datetime.date 2024 3 31) 1)
"add-months: Mar 31 to Apr 30 (30-day month clamp)")
(assert-equal test
&(Datetime.date 2025 1 15)
&(Datetime.add-months &(Datetime.date 2024 12 15) 1)
"add-months: Dec to Jan crosses year")
(assert-equal test
&(Datetime.date 2024 2 15)
&(Datetime.add-months &(Datetime.date 2024 3 15) -1)
"add-months: negative, Mar to Feb")
(assert-equal test
&(Datetime.date 2023 12 15)
&(Datetime.add-months &(Datetime.date 2024 1 15) -1)
"add-months: negative, Jan to Dec crosses year")
(assert-equal test
&(Datetime.date 2025 1 15)
&(Datetime.add-months &(Datetime.date 2024 1 15) 12)
"add-months: 12 months = 1 year")
(assert-equal test
&(Datetime.date 2022 1 15)
&(Datetime.add-months &(Datetime.date 2024 1 15) -24)
"add-months: -24 months = -2 years")
(assert-equal test
&(Datetime.date 2024 7 31)
&(Datetime.add-months &(Datetime.date 2024 5 31) 2)
"add-months: May 31 + 2 = Jul 31 (no clamp needed)")
(assert-equal test
&(Datetime.init 2024
2
15
(Maybe.Just 10)
(Maybe.Just 30)
(Maybe.Just 45)
(Maybe.Nothing)
(Maybe.Nothing))
&(Datetime.add-months
&(Datetime.init 2024
1
15
(Maybe.Just 10)
(Maybe.Just 30)
(Maybe.Just 45)
(Maybe.Nothing)
(Maybe.Nothing))
1)
"add-months: preserves time components")

; --- Datetime.add-years ---
(assert-equal test
&(Datetime.date 2025 3 15)
&(Datetime.add-years &(Datetime.date 2024 3 15) 1)
"add-years: simple +1")
(assert-equal test
&(Datetime.date 2025 2 28)
&(Datetime.add-years &(Datetime.date 2024 2 29) 1)
"add-years: Feb 29 to non-leap year clamps to 28")
(assert-equal test
&(Datetime.date 2028 2 29)
&(Datetime.add-years &(Datetime.date 2024 2 29) 4)
"add-years: Feb 29 to next leap year stays 29")
(assert-equal test
&(Datetime.date 2023 3 15)
&(Datetime.add-years &(Datetime.date 2024 3 15) -1)
"add-years: negative, -1 year")
(assert-equal test
&(Datetime.date 2023 2 28)
&(Datetime.add-years &(Datetime.date 2024 2 29) -1)
"add-years: Feb 29 backward to non-leap clamps to 28")
(assert-equal test
&(Datetime.date 2024 7 15)
&(Datetime.add-years &(Datetime.date 2024 7 15) 0)
"add-years: +0 is identity")
(assert-equal test
&(Datetime.date 1900 2 28)
&(Datetime.add-years &(Datetime.date 2000 2 29) -100)
"add-years: 2000 Feb 29 -100 to 1900 (not leap) clamps to 28")
(assert-equal test
&(Datetime.date 2400 2 29)
&(Datetime.add-years &(Datetime.date 2000 2 29) 400)
"add-years: 2000 Feb 29 +400 to 2400 (leap) stays 29")
(assert-equal test
&(Datetime.init 2025
3
15
(Maybe.Just 14)
(Maybe.Just 30)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing))
&(Datetime.add-years
&(Datetime.init 2024
3
15
(Maybe.Just 14)
(Maybe.Just 30)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing))
1)
"add-years: preserves time components"))
58 changes: 57 additions & 1 deletion time.carp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -917,7 +917,63 @@ optional ones.")
(/= sa sb) (< sa sb)
(< (Maybe.from @(nanoseconds a) 0)
(Maybe.from @(nanoseconds b) 0))))))))))
(implements < Datetime.<))
(implements < Datetime.<)

(doc diff "returns the signed difference in seconds between `a` and `b`.

The result is positive when `a` is later than `b`, and negative when `a` is
earlier. This is a timezone-unaware comparison, similar to `>` and `<`.")
(defn diff [a b]
(let [ord-a (to-ordinal a)
ord-b (to-ordinal b)
time-a (+ (* (Maybe.from @(hours a) 0) HOUR)
(+ (* (Maybe.from @(minutes a) 0) MINUTE)
(Maybe.from @(seconds a) 0)))
time-b (+ (* (Maybe.from @(hours b) 0) HOUR)
(+ (* (Maybe.from @(minutes b) 0) MINUTE)
(Maybe.from @(seconds b) 0)))]
(+ (* (- ord-a ord-b) DAY) (- time-a time-b))))

(doc add-months "adds `n` months to the `Datetime` `dt`.

If the resulting month has fewer days than the original day, the day is clamped
to the last day of the month. For example, adding 1 month to January 31 yields
February 28 (or 29 in a leap year).

`n` may be negative to subtract months.")
(defn add-months [dt n]
(let [total (+ (+ (* @(year dt) 12) (Int.dec @(month dt))) n)
new-year (div- total 12)
new-month (+ (mod- total 12) 1)
max-day (days-in-month new-year new-month)
new-day (min @(day dt) max-day)]
(init new-year
new-month
new-day
@(hours dt)
@(minutes dt)
@(seconds dt)
@(nanoseconds dt)
@(tz dt))))

(doc add-years "adds `n` years to the `Datetime` `dt`.

If the date is February 29 and the resulting year is not a leap year, the day is
clamped to February 28.

`n` may be negative to subtract years.")
(defn add-years [dt n]
(let [new-year (+ @(year dt) n)
max-day (days-in-month new-year @(month dt))
new-day (min @(day dt) max-day)]
(init new-year
@(month dt)
new-day
@(hours dt)
@(minutes dt)
@(seconds dt)
@(nanoseconds dt)
@(tz dt)))))

(deftype Timedelta [seconds- Int])

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