//! # Property cardinality
//!
//! How many times a property may appear in a card, per RFC 6350 section 6.
/// The RFC 6350 section 6 property multiplicity: how many times a property may
/// appear in a card. Prop multiplicity, not value structure, so it is not
/// derivable from the value kind (`FN` and `NOTE` are both text but differ).
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum VcardPropCardinality {
/// Exactly one (required, single).
ExactlyOne,
/// At most one (optional, single).
AtMostOne,
/// One or more (required, repeatable).
OneOrMore,
/// Any number, including zero (optional, repeatable).
Any,
}