Enum CenteringTransition 

pub enum CenteringTransition {
    Continue,
    Retain,
    SmoothShift,
    RoughShift,
    Null,
}

Centering transition type between successive utterances.

Transitions describe how the discourse focus shifts (or doesn’t) between utterances. The preference ordering predicts processing difficulty:

CONTINUE > RETAIN > SMOOTH-SHIFT > ROUGH-SHIFT

Texts with more CONTINUE transitions are easier to process because they maintain a consistent topic focus.

Transition Rules

Transition	Cb(U_n) = Cb(U_{n-1})?	Cb(U_n) = Cp(U_n)?
CONTINUE	Yes	Yes
RETAIN	Yes	No
SMOOTH-SHIFT	No	Yes
ROUGH-SHIFT	No	No

Example

use anno::discourse::centering::CenteringTransition;

// CONTINUE is most coherent
assert!(CenteringTransition::Continue.coherence_score() >
        CenteringTransition::Retain.coherence_score());

// Check transition type
assert!(CenteringTransition::Continue.is_continuing());
assert!(CenteringTransition::SmoothShift.is_shifting());

Variants

Continue

Cb(U_n) = Cb(U_{n-1}) AND Cb(U_n) = Cp(U_n). The discourse continues about the same entity, which remains most salient. This is the most coherent transition.

Retain

Cb(U_n) = Cb(U_{n-1}) AND Cb(U_n) != Cp(U_n). Same topic, but another entity is now more salient—signals an upcoming shift.

SmoothShift

Cb(U_n) != Cb(U_{n-1}) AND Cb(U_n) = Cp(U_n). Topic shift to a new entity, which is established as most salient.

RoughShift

Cb(U_n) != Cb(U_{n-1}) AND Cb(U_n) != Cp(U_n). Topic shift, but the new topic isn’t even the most salient entity. This is the least coherent transition.

Null

No Cb exists (discourse-initial or no entity from previous utterance realized).

Implementations

impl CenteringTransition

pub const fn coherence_score(&self) -> f64

Coherence score for this transition (higher = more coherent).

pub const fn is_continuing(&self) -> bool

Is this a continuing transition (same Cb)?

pub const fn is_shifting(&self) -> bool

Is this a shifting transition (different Cb)?

pub const fn as_str(&self) -> &'static str

Human-readable label.

Trait Implementations

impl Clone for CenteringTransition

fn clone(&self) -> CenteringTransition

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CenteringTransition

impl Debug for CenteringTransition

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

Formats the value using the given formatter.

impl Default for CenteringTransition

fn default() -> CenteringTransition

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for CenteringTransition

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for CenteringTransition

impl Hash for CenteringTransition

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 PartialEq for CenteringTransition

fn eq(&self, other: &CenteringTransition) -> 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 Serialize for CenteringTransition

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 StructuralPartialEq for CenteringTransition