Struct Chain 

pub struct Chain<I: ?Sized, O> { /* private fields */ }

Typed first-match-wins rule chain with a mandatory fallback.

Implementations

impl<I: ?Sized, O> Chain<I, O>

pub fn new<F>(fallback: F) -> Self

where F: Fn(&I) -> O + Send + Sync + 'static,

Construct an empty chain with the given fallback. Adding rules via with_rule extends the chain. The fallback is mandatory at construction — Chain::evaluate is total.

pub fn with_rule<R>(self, rule: R) -> Self

where R: Fn(&I) -> Option<O> + Send + Sync + 'static,

Append a rule. Returns self for fluent chaining.

pub fn rule_count(&self) -> usize

Number of rules in the chain (excludes the fallback).

pub fn evaluate(&self, input: &I) -> O

Evaluate the chain on an input. Returns the first rule’s Some(...) output, else the fallback’s value. Total: always returns a value.

Trait Implementations

impl<I: ?Sized, O> Classifier<I, O> for Chain<I, O>

fn classify(&self, input: &I) -> O

Classify one input. Pure — no side effects, deterministic for the same input.

impl<I: ?Sized, O> Debug for Chain<I, O>

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

Formats the value using the given formatter.