Merge pull request #7456 from data-man/cmp_datetime

Comparing datetimes

lib/pure/times.nim

@@ -274,6 +274,18 @@ proc toTime*(dt: DateTime): Time {.tags: [], raises: [], benign.} =
   # so we need to compensate for that here.
   result.inc dt.utcOffset
 
+proc `<`*(a, b: DateTime): bool =
+  ## Returns true iff ``a < b``, that is iff a happened before b.
+  return a.toTime < b.toTime
+
+proc `<=` * (a, b: DateTime): bool =
+  ## Returns true iff ``a <= b``.
+  return a.toTime <= b.toTime
+
+proc `==`*(a, b: DateTime): bool =
+  ## Returns true if ``a == b``, that is if both dates represent the same point in datetime.
+  return a.toTime == b.toTime
+
 proc initDateTime(zt: ZonedTime, zone: Timezone): DateTime =
   let adjTime = zt.adjTime.int64
   let epochday = (if adjTime >= 0: adjTime else: adjTime - (secondsInDay - 1)) div secondsInDay

tests/stdlib/ttimes.nim

@@ -367,4 +367,12 @@ suite "ttimes":
     check $(dt - 1.months) == "2017-02-15T00:00:00+00:00"
     dt = initDateTime(31, mMar, 2017, 00, 00, 00, utc())
     # This happens due to monthday overflow. It's consistent with Phobos.
-    check $(dt - 1.months) == "2017-03-03T00:00:00+00:00"
+    check $(dt - 1.months) == "2017-03-03T00:00:00+00:00"
+
+  test "compare datetimes":
+    var dt1 = now()
+    var dt2 = dt1
+    check dt1 == dt2
+    check dt1 <= dt2
+    dt2 = dt2 + 1.seconds
+    check dt1 < dt2