Struct SnapshotClock 

pub struct SnapshotClock { /* private fields */ }

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

Excel samples the clock ONCE per recalculation: every NOW() / TODAY() call within a single recalc — including all iteration passes of an iterating SCC — observes the same instant, and the sample only advances on the next recalculation. A raw SystemClock violates this (each call reads the OS clock, so NOW() drifts between SCC settle passes and even between two cells of one acyclic pass).

The engine wraps its configured clock in SnapshotClock and calls SnapshotClock::refresh once at the start of every evaluation request; builtins then read the frozen sample via the normal ClockProvider API.

Implementations

impl SnapshotClock

pub fn new(inner: Arc<dyn ClockProvider>) -> Self

Wrap inner, taking an initial sample immediately.

pub fn refresh(&self)

Re-sample the underlying clock. Called once per evaluation request.

Trait Implementations

impl ClockProvider for SnapshotClock

fn timezone(&self) -> &TimeZoneSpec

fn now(&self) -> NaiveDateTime

fn today(&self) -> NaiveDate

impl Debug for SnapshotClock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.