Struct ISO

pub struct ISO { /* private fields */ }

Represents a date in the ISO-8601 week-date calendar

Introduction

The ISO-8601 week-date is essentially an alternative naming system for Gregorian dates. Instead of dividing a year into months, the ISO-8601 week-date divides the year into weeks.

Despite being derived from the Gregorian calendar, the ISO-8601 has a different year start and year end than the Gregorian. If the Gregorian year X ends in the middle of the ISO week, the next days may be in Gregorian year X+1 and ISO year X.

Basic Structure

Each year is divided into 52 weeks, except for “long years” which have 53 weeks. These are common weeks with 7 days each, and start on Monday.

A long year occurs if the corresponding Gregorian year starts or ends on a Thursday.

Representation and Examples

The most obvious ways to create an ISO struct is to convert from the Gregorian, or to aggregate the year, week number and weekday.

use radnelac::calendar::*;
use radnelac::day_count::*;
use radnelac::day_cycle::*;

let g = Gregorian::try_new(2025, GregorianMonth::May, 15).unwrap();
let i = g.convert::<ISO>();
assert_eq!(i, ISO::try_new(2025, 20, Weekday::Thursday).unwrap());

Further reading

• Wikipedia
• Rachel by the Bay
  • describes the confusion of intermingling documentation for ISO and Gregorian dates

Implementations

impl ISO

pub fn try_new(year: i32, week: u8, day: Weekday) -> Result<Self, CalendarError>

Attempt to create a new ISO week date

pub fn year(self) -> i32

pub fn week(self) -> NonZero<u8>

pub fn day(self) -> Weekday

Note that the numeric values of the Weekday enum are not consistent with ISO-8601. Use day_num for the numeric day number.

pub fn day_num(self) -> u8

Represents Sunday as 7 instead of 0, as required by ISO-8601.

pub fn new_year(year: i32) -> Self

Trait Implementations

impl Clone for ISO

fn clone(&self) -> ISO

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ISO

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

Formats the value using the given formatter.

impl Display for ISO

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

Formats the value using the given formatter.

impl Epoch for ISO

fn epoch() -> Fixed

impl FromFixed for ISO

fn from_fixed(fixed_date: Fixed) -> ISO

impl HasLeapYears for ISO

fn is_leap(i_year: i32) -> bool

true if a the given year is a leap year.

impl PartialEq for ISO

fn eq(&self, other: &ISO) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for ISO

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PresetDisplay for ISO

fn long_date(&self) -> String

Format a date in a calendar-specific long format

fn short_date(&self) -> String

Format a date in a calendar-specific short format

fn supported_display_lang(lang: Language) -> bool

Checks if language is supported

fn preset_str(&self, lang: Language, preset: PresetFormat<'_>) -> String

Format a date in any PresetFormat

impl Quarter for ISO

fn quarter(self) -> NonZero<u8>

Calculate the quarter associated with a particular date.

impl ToFixed for ISO

fn to_fixed(self) -> Fixed

fn convert<T: FromFixed>(self) -> T

impl AllowYearZero for ISO

impl CalculatedBounds for ISO

impl Copy for ISO

impl DisplayMomentItem for ISO

impl StructuralPartialEq for ISO