Enum Requirement 

pub enum Requirement {
    Required,
    Optional,
}

Whether something is REQUIRED to present or answer an interaction faithfully, or merely preferred.

This is the axis ADR law 5 turns on: unknown REQUIRED behavior fails closed; unknown OPTIONAL behavior degrades visibly. Without it a consumer that cannot satisfy a demand has only one move for both cases, and whichever it picks is wrong half the time — silently dropping a mandatory secret field, or refusing a document that merely wanted a diagram.

One vocabulary, deliberately: controls and surface features both use it, so a wire consumer learns the distinction once. On a control it means “the response must answer this FIELD” — which is only coherent because a choice is one field with many options, not many fields.

Variants

Required

Must be satisfiable. If it is not, the interaction is Unsupported and no answer may be guessed.

Optional

Preferred. If it is not satisfiable, the interaction proceeds and the shortfall is reported visibly.

Trait Implementations

impl Clone for Requirement

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Requirement

impl Debug for Requirement

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Requirement

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Requirement

impl PartialEq for Requirement

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for Requirement

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Requirement