Struct Contact 

pub struct Contact {
    pub extent: Option<[NonZeroU32; 2]>,
}

A contact: the span of a shared face along which two places simply meet (spec-0053 §4).

What a contact MEANS

The boundary is continuous ground. The derivation writes no wall along the span — and wall as ever outside it — and crossing is legitimate anywhere along it the step rule admits. It is not a wide door: DW0829’s standard-name resolution and sill rule are portal checks and do not apply, because a contact has no opening name to resolve and no single sill. Calling a 55-cell front a door would make every downstream door check wrong.

What the author allocates and what the engine measures

The author allocates where the places meet. The engine measures the crossing profile from assembled bytes — which columns of the span a body actually crosses under the step rule — and DW0877 refuses a contact nothing can cross. “This face is fine” is never a declaration this engine accepts.

Seams stay allocated, never discovered: the span is the edge’s allocation set for DW0838, so a crossing outside it is still a refusal.

Fields

extent: Option<[NonZeroU32; 2]>

The span, [u, v] in cells on the face’s own two in-plane axes, anchored at the seam’s at.

Omitted, the span runs from at to the far edge of the shared face on both axes — which is how a contact along the whole of a face is written, by putting at at the face’s low corner. DW0828’s refusal prints that corner, so the number an author needs is in the message they would already be reading.

There is no width standard and no length here, and both absences are the design (spec-0053 §7).

Trait Implementations

impl Clone for Contact

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Contact

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Contact

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl JsonSchema for Contact

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl PartialEq for Contact

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for Contact

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 Contact