std::time

Stability: Stable — durations in whole milliseconds.

std::time declares Duration, the one type of time in std. Every time in the library (tween lengths, delays, text speed, pauses, auto-mode delays) is a Duration of whole milliseconds. There are no unit strings and no frame counts.

Every item is ordinary Kagari code (no #[builtin]), and every function is a const fn. The prelude imports Duration, ms and secs.

Overview

Struct: Duration

pub struct Duration {
    pub ms: u32,
}

• ms u32 — the length in milliseconds.
• Kind: — · Builtin: no

A Duration is plain data: it can be built with a struct literal, compared with == (it is Eq), and its field read directly. It holds a Rust integer, so it is not finite: the story uses durations only in constant expressions, which are folded.

Overflow or underflow of a Duration is an evaluation error; in const evaluation it is E4013.

Duration::plus(self, other)

pub const fn plus(self, other: Duration) -> Duration

• other Duration — the duration to add.
• Returns: Duration — the sum of the two durations.
• Kind: const fn · Builtin: no

Duration::times(self, n)

pub const fn times(self, n: u32) -> Duration

• n u32 — the factor.
• Returns: Duration — this duration n times.
• Kind: const fn · Builtin: no

Duration::div(self, n)

pub const fn div(self, n: u32) -> Duration

• n u32 — the divisor.
• Returns: Duration — this duration divided by n, rounded down.
• Kind: const fn · Builtin: no

div truncates: ms(1000).div(3) is ms(333). n == 0 is a division by zero (E4002 in const evaluation).

const BEAT: Duration = ms(400);
const BAR: Duration = BEAT.times(4);
const HALF_BAR: Duration = BAR.div(2);
const INTRO: Duration = secs(2).plus(HALF_BAR);

Constant: ZERO

pub const ZERO: Duration = Duration { ms: 0 };

No time at all. Not in the prelude: use std::time::ZERO;. As the text_speed setting, ZERO shows text instantly.

Function: ms(n)

pub const fn ms(n: u32) -> Duration

• n u32 — milliseconds.
• Returns: Duration — n milliseconds.
• Kind: const fn · Builtin: no

Function: secs(n)

pub const fn secs(n: u32) -> Duration

• n u32 — seconds.
• Returns: Duration — n seconds, that is n * 1000 milliseconds.
• Kind: const fn · Builtin: no

secs(n) with n * 1000 beyond u32 overflows.