Enum Edtf

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pub enum Edtf {
    Date(Date),
    DateTime(DateTime),
    Interval(Interval),
    Set(Set),
}

Expand description

Any parsed EDTF expression.

Variants§

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Date(Date)

A single date.

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DateTime(DateTime)

A date with time of day (level 0 only).

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Interval(Interval)

A time interval.

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Set(Set)

A set of dates (level 2).

Implementations§

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impl Edtf

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pub fn bounds(&self) -> Bounds

Compute the earliest/latest calendar-day bounds of this expression.

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impl Edtf

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pub fn values(&self) -> Result<Values, Unenumerable>

Enumerate the concrete calendar values this expression denotes, each at its own precision (decisions D24–D29 in docs/spec-notes.md).

The iterator is lazy — state is proportional to the number of set elements, never to the number of values — so pathological cardinalities (XXXX-XX-XX denotes ~3.65 million days) stream without allocation. Errors are structural and complete at construction: iteration itself cannot fail.

use edtf_core::Edtf;

// ISO 8601-2 §6.4 Example 1, expanded exactly as the spec does:
let set = Edtf::parse("{1667,1668,1670..1672}").unwrap();
let years: Vec<String> = set.values().unwrap().map(|v| v.to_string()).collect();
assert_eq!(years, ["1667", "1668", "1670", "1671", "1672"]);

// Unspecified digits enumerate their valid completions (§9.2.2):
let masked = Edtf::parse("1985-0X-31").unwrap();
let months: Vec<String> = masked.values().unwrap().map(|v| v.to_string()).collect();
assert_eq!(
    months,
    [
        "1985-01-31",
        "1985-03-31",
        "1985-05-31",
        "1985-07-31",
        "1985-08-31"
    ]
);

// Intervals denote one extent, not a collection:
assert!(Edtf::parse("2004/2005").unwrap().values().is_err());

§Errors

Unenumerable when the value denotes no finite collection: an interval, a set with an unbounded ..date/date.. element, or a year sweep beyond the numeric range this library computes with.

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impl Edtf

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pub fn relation(&self, other: &Self) -> Relations

The three-valued temporal relation between this expression and other, computed over the two Edtf::bounds regions (see the semantics note in this module’s documentation).

use edtf_core::{Edtf, Modality, Relation};

let a = Edtf::parse("1985~").unwrap();
let b = Edtf::parse("199X").unwrap();
assert_eq!(a.relation(&b).definite(), Some(Relation::Before));

let c = Edtf::parse("198X").unwrap();
let d = Edtf::parse("1985").unwrap();
// 198X may fall before, on, after or around 1985 — nothing asserted.
assert_eq!(c.relation(&d).definite(), None);
assert!(c.relation(&d).is_possible(Relation::Before));
assert!(c.relation(&d).is_possible(Relation::After));
assert!(c.relation(&d).is_possible(Relation::Contains));

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impl Edtf

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pub fn parse(input: &str) -> Result<Self, ParseError>

Parse an EDTF string (levels 0–2, ISO 8601-2:2019 Annex A).

§Errors

ParseError with a byte offset and message pointing at the first place the input stops being valid EDTF.

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pub fn level(&self) -> u8

The minimum EDTF conformance level (0, 1 or 2) able to express this value. Semantically equivalent spellings classify identically: e.g. ?1985-?04-?12 reports level 1 because 1985-04-12? means the same.

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