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fix Datetime comparisons and add-seconds off-by-one #4

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fix Datetime comparisons and add-seconds off-by-one #4

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58 changes: 53 additions & 5 deletions test/time.carp
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Original file line number Diff line number Diff line change
Expand Up @@ -318,10 +318,8 @@
(Maybe.Nothing))
&(Timedelta.days 1)))
"Timedelta.add 1 day advances the day")
; NOTE: add-seconds has an off-by-one bug with negative values;
; subtracting 5 minutes from 00:00:00 yields 23:54:59 instead of 23:55:00.
(assert-equal test
&@"23:54:59"
&@"23:55:00"
&(Datetime.isotime
&(Timedelta.sub
&(Datetime.init 2024
Expand All @@ -333,7 +331,7 @@
(Maybe.Nothing)
(Maybe.Nothing))
&(Timedelta.minutes 5)))
"Timedelta.sub 5 minutes wraps back (off-by-one bug)")
"Timedelta.sub 5 minutes wraps back")

; --- Datetime.strptime ---
; basic date parsing
Expand Down Expand Up @@ -570,4 +568,54 @@
(Maybe.Nothing))
"%Y-%m-%d %H:%M:%S")
"%Y-%m-%d %H:%M:%S"))
"strptime roundtrips with strftime for datetime"))
"strptime roundtrips with strftime for datetime")

; --- Datetime comparison operators ---
(assert-true test
(= &(Datetime.date 2024 3 15) &(Datetime.date 2024 3 15))
"equal dates are equal")
(assert-false test
(= &(Datetime.date 2024 1 15) &(Datetime.date 2024 2 15))
"different months are not equal")
(assert-true test
(> &(Datetime.date 2024 3 15) &(Datetime.date 2024 2 15))
"greater-than with same year different month")
(assert-true test
(< &(Datetime.date 2023 12 31) &(Datetime.date 2024 1 1))
"less-than with year priority over month")
(assert-false test
(> &(Datetime.date 2024 3 15) &(Datetime.date 2024 3 15))
"equal datetimes return false for >")
(assert-false test
(< &(Datetime.date 2024 3 15) &(Datetime.date 2024 3 15))
"equal datetimes return false for <")

; --- add-seconds negative edge cases ---
(assert-equal test
&@"23:59:59"
&(Datetime.isotime
&(Datetime.add-seconds
&(Datetime.init 2024
1
2
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing))
-1))
"subtract 1 second from 00:00:00")
(assert-equal test
&@"22:58:59"
&(Datetime.isotime
&(Datetime.add-seconds
&(Datetime.init 2024
1
2
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Just 0)
(Maybe.Nothing)
(Maybe.Nothing))
-3661))
"subtract 3661 seconds (1h1m1s) from 00:00:00"))
64 changes: 46 additions & 18 deletions time.carp
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Original file line number Diff line number Diff line change
Expand Up @@ -241,31 +241,34 @@ in the range of `1` to `365` or `366`, depending on whether it’s a leap year."
(defn mod- [a n]
(- a (* n (to-int (floor (/ (Double.from-int a) (Double.from-int n)))))))

(hidden div-)
(defn div- [a n] (to-int (floor (/ (Double.from-int a) (Double.from-int n)))))

(doc add-seconds "adds a number of seconds `n` to a `Datetime`.

If `n` is negative, it will be subtracted instead.")
(defn add-seconds [d n]
(if (neg? n)
(let-do [nd @d
s (Maybe.from @(seconds d) 0)
a (dec (+ s n))]
a (+ s n)]
(set-seconds! &nd (Maybe.Just (mod- a 60)))
(if (>= a 0)
nd
(let-do [m (/ a 60)
(let-do [m (div- a 60)
dm (Maybe.from @(minutes d) 0)
ma (dec (+ m dm))]
ma (+ m dm)]
(set-minutes! &nd (Maybe.Just (mod- ma 60)))
(if (>= ma 0)
nd
(let-do [h (/ ma 60)
(let-do [h (div- ma 60)
dh (Maybe.from @(hours d) 0)
ha (dec (+ h dh))]
ha (+ h dh)]
(set-hours! &nd (Maybe.Just (mod- ha 24)))
(if (>= ha 0)
nd
(let-do [ord (to-ordinal d)
nnd (from-ordinal (dec (+ ord (/ ha 24))))]
nnd (from-ordinal (+ ord (div- ha 24)))]
(set-day! &nd @(day &nnd))
(set-month! &nd @(month &nnd))
(set-year! &nd @(year &nnd))
Expand Down Expand Up @@ -862,6 +865,7 @@ Example:
optional ones.")
(defn = [a b]
(and (= (year a) (year b))
(= (month a) (month b))
(= (day a) (day b))
(= (hours a) (hours b))
(= (minutes a) (minutes b))
Expand All @@ -873,22 +877,46 @@ optional ones.")

(doc > "is defined as the timezone-unaware comparison of `a` and `b`.")
(defn > [a b]
(or (> @(year a) @(year b))
(> @(day a) @(day b))
(> (Maybe.from @(hours a) 0) (Maybe.from @(hours b) 0))
(> (Maybe.from @(minutes a) 0) (Maybe.from @(minutes b) 0))
(> (Maybe.from @(seconds a) 0) (Maybe.from @(seconds b) 0))
(> (Maybe.from @(nanoseconds a) 0) (Maybe.from @(nanoseconds b) 0))))
(cond
(/= @(year a) @(year b)) (> @(year a) @(year b))
(/= @(month a) @(month b)) (> @(month a) @(month b))
(/= @(day a) @(day b)) (> @(day a) @(day b))
(let [ha (Maybe.from @(hours a) 0)
hb (Maybe.from @(hours b) 0)]
(cond
(/= ha hb) (> ha hb)
(let [ma (Maybe.from @(minutes a) 0)
mb (Maybe.from @(minutes b) 0)]
(cond
(/= ma mb) (> ma mb)
(let [sa (Maybe.from @(seconds a) 0)
sb (Maybe.from @(seconds b) 0)]
(cond
(/= sa sb) (> sa sb)
(> (Maybe.from @(nanoseconds a) 0)
(Maybe.from @(nanoseconds b) 0))))))))))
(implements > Datetime.>)

(doc < "is defined as the timezone-unaware comparison of `a` and `b`.")
(defn < [a b]
(or (< @(year a) @(year b))
(< @(day a) @(day b))
(< (Maybe.from @(hours a) 0) (Maybe.from @(hours b) 0))
(< (Maybe.from @(minutes a) 0) (Maybe.from @(minutes b) 0))
(< (Maybe.from @(seconds a) 0) (Maybe.from @(seconds b) 0))
(< (Maybe.from @(nanoseconds a) 0) (Maybe.from @(nanoseconds b) 0))))
(cond
(/= @(year a) @(year b)) (< @(year a) @(year b))
(/= @(month a) @(month b)) (< @(month a) @(month b))
(/= @(day a) @(day b)) (< @(day a) @(day b))
(let [ha (Maybe.from @(hours a) 0)
hb (Maybe.from @(hours b) 0)]
(cond
(/= ha hb) (< ha hb)
(let [ma (Maybe.from @(minutes a) 0)
mb (Maybe.from @(minutes b) 0)]
(cond
(/= ma mb) (< ma mb)
(let [sa (Maybe.from @(seconds a) 0)
sb (Maybe.from @(seconds b) 0)]
(cond
(/= sa sb) (< sa sb)
(< (Maybe.from @(nanoseconds a) 0)
(Maybe.from @(nanoseconds b) 0))))))))))
(implements < Datetime.<))

(deftype Timedelta [seconds- Int])
Expand Down
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