Struct Nu 

pub struct Nu<F: HKT, Seed> {
    pub seed: Seed,
    pub coalgebra: Box<dyn Fn(&Seed) -> F::Of<Seed>>,
}

The greatest fixed point of a functor F.

Nu<F, Seed> represents a potentially infinite corecursive structure. It stores a seed value and a coalgebra that can observe one layer at a time.

The Seed type parameter is exposed because Rust lacks existential types. This is the same pragmatic compromise used by Lan in karpal-free.

Fields

seed: Seed

coalgebra: Box<dyn Fn(&Seed) -> F::Of<Seed>>

Implementations

impl<F: HKT, Seed> Nu<F, Seed>

pub fn new( seed: Seed, coalgebra: impl Fn(&Seed) -> F::Of<Seed> + 'static, ) -> Self

Create a Nu from a seed and a coalgebra.

pub fn observe(&self) -> F::Of<Seed>

Apply the coalgebra once to observe one layer.

pub fn to_fix(self) -> Fix<F>

where F: Functor, Seed: Clone,

Convert to Fix<F> by fully unfolding via anamorphism.

This will diverge for truly infinite structures — only call on coalgebras that eventually terminate.