commit a4c8a75380f18c3573c7aed1c03d0ad4a3aa3448
parent 2091016f6330db45bc614934728e43fa4c93ce9c
Author: triesap <tyson@radroots.org>
Date: Mon, 21 Sep 2026 12:58:36 +0000
core: implement source-anchored date resolution
Diffstat:
2 files changed, 115 insertions(+), 0 deletions(-)
diff --git a/src/hyf_core/normalization/dates.mojo b/src/hyf_core/normalization/dates.mojo
@@ -0,0 +1,92 @@
+from hyf_core.domain.time import DateOnly
+
+
+@fieldwise_init
+struct ResolvedDate(Copyable, Movable):
+ var resolution: String
+ var date: DateOnly
+ var ambiguity: String
+
+
+def _days_from_civil(year: Int, month: Int, day: Int) -> Int:
+ var y = year
+ var m = month
+ if m <= 2:
+ y -= 1
+ var era = y // 400
+ if y < 0 and y % 400 != 0:
+ era -= 1
+ var yoe = y - era * 400
+ var adjusted_month = m - 3 if m > 2 else m + 9
+ var doy = (153 * adjusted_month + 2) // 5 + day - 1
+ var doe = yoe * 365 + yoe // 4 - yoe // 100 + doy
+ return era * 146097 + doe - 719468
+
+
+def _civil_from_days(z: Int) raises -> DateOnly:
+ var adjusted = z + 719468
+ var era = adjusted // 146097
+ if adjusted < 0 and adjusted % 146097 != 0:
+ era -= 1
+ var doe = adjusted - era * 146097
+ var yoe = (doe - doe // 1460 + doe // 36524 - doe // 146096) // 365
+ var y = yoe + era * 400
+ var doy = doe - (365 * yoe + yoe // 4 - yoe // 100)
+ var mp = (5 * doy + 2) // 153
+ var d = doy - (153 * mp + 2) // 5 + 1
+ var m = mp + 3 if mp < 10 else mp - 9
+ if m <= 2:
+ y += 1
+ return DateOnly(year=y, month=m, day=d)
+
+
+def weekday_index(date: DateOnly) -> Int:
+ # 0 = Monday ... 6 = Sunday
+ var days = _days_from_civil(date.year, date.month, date.day)
+ return (((days + 3) % 7) + 7) % 7
+
+
+def _weekday_number(name: String) raises -> Int:
+ var lowered = name.lower()
+ var names = ["monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday"]
+ for index in range(len(names)):
+ if lowered == names[index]:
+ return index
+ raise Error("unknown weekday: " + name)
+
+
+def resolve_weekday(
+ reference: DateOnly, weekday_name: String, direction: String
+) raises -> ResolvedDate:
+ var target = _weekday_number(weekday_name)
+ var current = weekday_index(reference)
+ var delta = (target - current + 7) % 7
+ if direction == "next":
+ if delta == 0:
+ delta = 7
+ elif direction != "on_or_after":
+ raise Error("direction must be 'next' or 'on_or_after'")
+ var base = _days_from_civil(reference.year, reference.month, reference.day)
+ return ResolvedDate(
+ resolution="resolved",
+ date=_civil_from_days(base + delta),
+ ambiguity="none",
+ )
+
+
+def resolve_relative_expression(
+ expression: String, reference: DateOnly
+) raises -> ResolvedDate:
+ var lowered = expression.lower()
+ var base = _days_from_civil(reference.year, reference.month, reference.day)
+ if lowered == "today":
+ return ResolvedDate(
+ resolution="resolved", date=reference.copy(), ambiguity="none"
+ )
+ if lowered == "tomorrow":
+ return ResolvedDate(
+ resolution="resolved",
+ date=_civil_from_days(base + 1),
+ ambiguity="none",
+ )
+ return resolve_weekday(reference, lowered, "next")
diff --git a/tests/test_domain.mojo b/tests/test_domain.mojo
@@ -255,3 +255,26 @@ def test_time_types_distinguish_source_and_evaluation() raises:
_ = date_only(2026, 13, 1)
with assert_raises():
_ = timestamp(1, "")
+
+
+from hyf_core.normalization.dates import (
+ resolve_relative_expression,
+ resolve_weekday,
+ weekday_index,
+)
+
+
+def test_source_anchored_relative_date_replay() raises:
+ var monday = date_only(2026, 9, 21)
+ assert_equal(weekday_index(monday), 0)
+ var friday = resolve_relative_expression("Friday", monday)
+ assert_equal(friday.resolution, "resolved")
+ assert_equal(friday.date.year, 2026)
+ assert_equal(friday.date.month, 9)
+ assert_equal(friday.date.day, 25)
+ var same = resolve_weekday(monday, "Monday", "on_or_after")
+ assert_equal(same.date.day, 21)
+ var next = resolve_weekday(monday, "Monday", "next")
+ assert_equal(next.date.day, 28)
+ # Replay at a later evaluation time uses the same source reference.
+ assert_equal(resolve_relative_expression("Friday", monday).date.day, 25)
