Clarify that Duration is an "accurate" duration

The ISO 8601 format includes both "nominal" (year, month, week, and
day) and "accurate" (hour, minute, and second) components. However, the
`Duration` type only represents an "accurate" duration because
arithmetic with nominal components is not defined in ISO 8601.
This commit is contained in:
Jim Turner 2016-10-04 19:07:11 -04:00
parent e308e8e929
commit 881e6c2dcc
1 changed files with 13 additions and 6 deletions

View File

@ -49,11 +49,13 @@
//! //!
//! ### Duration //! ### Duration
//! //!
//! [**`Duration`**](./struct.Duration.html) //! [**`Duration`**](./struct.Duration.html) represents the magnitude of a time
//! represents the magnitude of a time span. `Duration` used to be provided by Chrono. //! span. Note that this is an "accurate" duration represented as seconds and
//! It has been moved to the `time` crate as the //! nanoseconds and does not represent "nominal" components such as days or
//! [`time::Duration`](https://doc.rust-lang.org/time/time/struct.Duration.html) type, but is //! months. `Duration` used to be provided by Chrono. It has been moved to the
//! still re-exported from Chrono. //! `time` crate as the
//! [`time::Duration`](https://doc.rust-lang.org/time/time/struct.Duration.html)
//! type, but is still re-exported from Chrono.
//! //!
//! ### Date and Time //! ### Date and Time
//! //!
@ -351,7 +353,12 @@ macro_rules! try_opt {
mod div; mod div;
pub mod duration { pub mod duration {
//! ISO 8601 duration. //! ISO 8601 accurate duration.
//!
//! Note that this is an "accurate" (i.e. "exact") duration represented as
//! seconds and nanoseconds. It does not include the "nominal" components
//! (years, months, weeks, and days) in the ISO 8601 duration format
//! because arithmetic with nominal components is not defined in ISO 8601.
//! //!
//! This used to be a part of rust-chrono, //! This used to be a part of rust-chrono,
//! but has been subsequently merged into Rust's standard library. //! but has been subsequently merged into Rust's standard library.