Module timezone 

Structs

FixedClock

Deterministic clock implementation: always returns the configured instant.

SnapshotClock

Per-recalc snapshotting wrapper around a ClockProvider (spec formualizer-cycle-semantics-spec.md §7.11).

SystemClock

Default clock implementation: reads from the system clock.

Enums

TimeZoneSpec

Timezone specification for date/time calculations Excel behavior: always uses local timezone This enum allows future extensions while maintaining Excel compatibility

Traits

ClockProvider

Injectable clock provider for volatile date/time builtins.