time
host module
Wall-clock and monotonic time — unix timestamps, elapsed measurement, sleeping, ISO-8601 formatting.
use time — clocks and sleeping. Registering this module is a capability grant: scripts can read the clock and block their thread.
| function | signature |
|---|---|
| now_unix | () -> float (seconds since the epoch, sub-second precision) |
| now_millis | () -> int (milliseconds since the epoch) |
| instant | () -> float (monotonic, seconds since a process-wide anchor) |
| elapsed | (start) -> float (seconds since an instant()) |
| sleep | (ms) (blocks the VM thread; negatives clamp to zero) |
| format_iso | (ts) -> string (UTC ISO-8601 from unix seconds) |
The common use is a resource that converges on an *age* rather than on a state — a package cache refreshed within the last N minutes, say. Compare fs::metadata(stamp).modified against now, and prefer now_millis() / 1000 over now_unix() when the other side is an integer, so the comparison stays in integers.
ws
// Refresh when the stamp file is missing or older than max_age seconds.
fn stale(stamp: string, max_age: int) -> Result[bool, string] {
if !fs::is_file(stamp) { return Ok(true) }
let meta = fs::metadata(stamp)?
let modified = if let Some(m) = meta.get("modified") {
if let Some(ts) = m.as_int() { ts } else { 0 }
} else { 0 }
Ok(time::now_millis() / 1000 - modified > max_age)
}
Use instant/elapsed for durations, never a difference of now_unix calls — the wall clock can step backwards (NTP, a VM resuming from a snapshot) and the monotonic clock cannot.