Struct HistoricalDate 

pub struct HistoricalDate {
    pub year: i32,
    pub month: Option<u8>,
    pub day: Option<u8>,
    pub precision: DatePrecision,
}

A historical date that can represent BCE dates and partial precision.

Unlike chrono’s types, this can represent:

• BCE dates (negative years like -44 for 44 BCE)
• Partial dates (year only, year-month)
• Far-past dates beyond chrono’s range

ISO 8601 Representation

Follows ISO 8601 extended format:

• CE dates: “2024-03-15”, “2024-03”, “2024”
• BCE dates: “-0044-03-15” (44 BCE March 15)

Examples

use anno_core::types::HistoricalDate;

// Julius Caesar's death
let caesar_death = HistoricalDate::bce(44, 3, 15);
assert_eq!(caesar_death.to_iso8601(), "-0044-03-15");

// Modern date
let modern = HistoricalDate::ce(2024, 6, 15);
assert_eq!(modern.to_iso8601(), "2024-06-15");

// Year only
let year_only = HistoricalDate::year_only(1990);
assert_eq!(year_only.to_iso8601(), "1990");

Fields

year: i32

Year (negative for BCE, positive for CE) Year 0 does not exist in historical dating; -1 = 1 BCE, 1 = 1 CE

month: Option<u8>

Month (1-12), None if unknown

day: Option<u8>

Day (1-31), None if unknown

precision: DatePrecision

Precision of this date

Implementations

impl HistoricalDate

pub fn ce(year: i32, month: u8, day: u8) -> HistoricalDate

Create a CE (Common Era) date.

Examples

use anno_core::types::HistoricalDate;

let date = HistoricalDate::ce(2024, 6, 15);
assert_eq!(date.year, 2024);

pub fn bce(year: u32, month: u8, day: u8) -> HistoricalDate

Create a BCE (Before Common Era) date.

Internally stored as negative year.

Examples

use anno_core::types::HistoricalDate;

let date = HistoricalDate::bce(44, 3, 15);  // 44 BCE March 15
assert_eq!(date.year, -44);

pub fn year_only(year: i32) -> HistoricalDate

Create a year-only date.

pub fn year_month(year: i32, month: u8) -> HistoricalDate

Create a year-month date.

pub fn is_bce(&self) -> bool

Check if this is a BCE date.

pub fn format_year(&self) -> String

Get the year as a positive number with era suffix.

Examples

use anno_core::types::HistoricalDate;

let bce = HistoricalDate::bce(44, 3, 15);
assert_eq!(bce.format_year(), "44 BCE");

let ce = HistoricalDate::ce(2024, 6, 15);
assert_eq!(ce.format_year(), "2024 CE");

pub fn to_iso8601(&self) -> String

Convert to ISO 8601 string.

Examples

use anno_core::types::HistoricalDate;

let date = HistoricalDate::bce(44, 3, 15);
assert_eq!(date.to_iso8601(), "-0044-03-15");

pub fn parse(s: &str) -> Result<HistoricalDate, String>

Parse from ISO 8601 string.

Handles:

• “2024-06-15” (full CE date)
• “-0044-03-15” (full BCE date)
• “2024-06” (year-month)
• “2024” or “-0044” (year only)

Errors

Returns error if the string cannot be parsed.

pub fn parse_year(s: &str) -> Option<i32>

Extract just the year from an ISO 8601 string.

Useful for quick temporal comparisons without full parsing.

Trait Implementations

impl Clone for HistoricalDate

fn clone(&self) -> HistoricalDate

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HistoricalDate

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for HistoricalDate

fn deserialize<__D>( __deserializer: __D, ) -> Result<HistoricalDate, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for HistoricalDate

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

Formats the value using the given formatter.

impl FromStr for HistoricalDate

type Err = String

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<HistoricalDate, <HistoricalDate as FromStr>::Err>

Parses a string s to return a value of this type.

impl Hash for HistoricalDate

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for HistoricalDate

fn cmp(&self, other: &HistoricalDate) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for HistoricalDate

fn eq(&self, other: &HistoricalDate) -> 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 HistoricalDate

fn partial_cmp(&self, other: &HistoricalDate) -> 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 Serialize for HistoricalDate

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for HistoricalDate

impl Eq for HistoricalDate

impl StructuralPartialEq for HistoricalDate