Promonad

deep_causality_haft

Trait Promonad 

Source 
pub trait Promonad<P: HKT3Unbound> {
    // Required methods
    fn merge<A, B, C, F>(
        pa: P::Type<A, A, A>,
        pb: P::Type<B, B, B>,
        f: F,
    ) -> P::Type<C, C, C>
       where A: Satisfies<P::Constraint>,
             B: Satisfies<P::Constraint>,
             C: Satisfies<P::Constraint>,
             F: FnMut(A, B) -> C;
    fn fuse<A, B, C>(input_a: A, input_b: B) -> P::Type<A, B, C>
       where A: Satisfies<P::Constraint>,
             B: Satisfies<P::Constraint>,
             C: Satisfies<P::Constraint>;
}
Expand description

The Promonad trait models the “fusion” or “interaction” of two contexts to produce a third.

§Category Theory

This is related to Monoidal Functors and Day Convolution. It defines a mapping from the tensor product of two functors to a third functor: $$ F(A) \otimes G(B) \to H(A \otimes B) $$

In our Arity-3 definition $P<A, B, C>$, it acts as a “Pre-Arrow” or a specialized profunctor mapping $(A, B) \to C$.

§Use Cases

  • Tensor Contraction: Merging a Vector $u$ and a Dual Vector $v^*$ to produce a Scalar.
  • Quantum Entanglement: Combining Qubit A and Qubit B into an Entangled Pair C.
  • Force Calculation: Combining Current $J$ and Magnetic Field $B$ to produce Force $F$.

Required Methods§

Source

fn merge<A, B, C, F>( pa: P::Type<A, A, A>, pb: P::Type<B, B, B>, f: F, ) -> P::Type<C, C, C>
where A: Satisfies<P::Constraint>, B: Satisfies<P::Constraint>, C: Satisfies<P::Constraint>, F: FnMut(A, B) -> C,

Merges two contexts into a third.

§Arguments
  • pa: The first context (Input A).
  • pb: The second context (Input B).
  • f: A function to combine the inner values $A$ and $B$ into $C$.
Source

fn fuse<A, B, C>(input_a: A, input_b: B) -> P::Type<A, B, C>
where A: Satisfies<P::Constraint>, B: Satisfies<P::Constraint>, C: Satisfies<P::Constraint>,

Fusion: Directly combines two raw inputs into the interaction context.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§