Struct SumUniversal 

pub struct SumUniversal<A, B, Z> {
    pub left_branch: PhantomData<fn(A) -> Z>,
    pub right_branch: PhantomData<fn(B) -> Z>,
    pub description: String,
}

Witness of the universal property of Sum: given f: A → Z and g: B → Z, there is a unique mediating map Sum A B → Z.

Fields

left_branch: PhantomData<fn(A) -> Z>

The left branch.

right_branch: PhantomData<fn(B) -> Z>

The right branch.

description: String

Description of the universal property.

Implementations

impl<A, B, Z> SumUniversal<A, B, Z>

pub fn new(description: impl Into<String>) -> Self

Create a new SumUniversal witness.

pub fn mediate( &self, s: Coproduct<A, B>, f: impl FnOnce(A) -> Z, g: impl FnOnce(B) -> Z, ) -> Z

Apply the universal mediator using concrete functions.