Struct Prism 

pub struct Prism<S, A> { /* private fields */ }

A prism focusing on one variant of a sum type.

Implementations

impl<S: 'static, A: 'static> Prism<S, A>

pub fn new( preview: impl Fn(S) -> Option<A> + 'static, review: impl Fn(A) -> S + 'static, ) -> Self

Create a prism from preview and review functions.

pub fn preview(&self, s: S) -> Option<A>

Try to extract the focused value.

pub fn review(&self, a: A) -> S

Inject a value into the sum type.