mod result;
pub use result::{_Err, _Ok};
mod option;
pub use option::{_None, _Some};
/// Wrapper type
#[derive(Clone, Copy)]
#[repr(transparent)]
pub struct Prism
(pub(crate) P);
pub trait PrismPreview {
type Field;
fn preview(thing: T) -> Option;
}
pub trait PrismReview: PrismPreview {
fn review(thing: Self::Field) -> T;
}
impl PrismPreview for Prism
where
P: PrismPreview,
{
type Field = P::Field;
fn preview(thing: T) -> Option {
P::preview(thing)
}
}
impl PrismReview for Prism
where
P: PrismReview,
{
fn review(thing: Self::Field) -> T {
P::review(thing)
}
}
pub fn preview>(_prism: P, thing: T) -> Option {
P::preview(thing)
}
pub fn review>(_prism: P, thing: P::Field) -> T {
P::review(thing)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn preview_result() {
let a: Result = Ok(3);
assert_eq!(preview(_Ok, a), Some(3));
let a: Result = Err(3);
assert_eq!(preview(_Ok, a), None);
let a: Result = Ok(3);
assert_eq!(preview(_Err, a), None);
let a: Result = Err(3);
assert_eq!(preview(_Err, a), Some(3));
}
#[test]
fn preview_option() {
let a = Some(3);
assert_eq!(preview(_Some, a), Some(3));
let a = Some(3);
assert_eq!(preview(_None, a), Some(()));
let a: Option = None;
assert_eq!(preview(_Some, a), None);
let a: Option = None;
assert_eq!(preview(_None, a), Some(()));
}
#[test]
fn review_result() {
assert_eq!(review(_Ok, 3), Ok::(3));
assert_eq!(review(_Err, 3), Err::(3));
}
#[test]
fn review_option() {
assert_eq!(review(_Some, 3), Some(3));
assert_eq!(review(_None, ()), None::<()>);
}
}