radn-rs/src/func/classes/solo.rs
2023-05-20 06:02:51 +00:00

157 lines
3.4 KiB
Rust

//! Simplest sync [Monad].
//!
//! For async, see [`super::future`].
use crate::func::*;
#[derive(SharedFunctor, CovariantFunctor)]
pub struct SoloClass;
impl WeakFunctor for SoloClass {
type F<'a, A: 'a> = A;
}
impl Functor for SoloClass {
fn fmap<'a, A: 'a, B: 'a>(f: impl 'a + FnOnce(A) -> B, fa: Self::F<'a, A>) -> Self::F<'a, B> {
f(fa)
}
fn replace<'a, A: 'a, B: 'a>(fa: Self::F<'a, A>, b: B) -> Self::F<'a, B> {
drop(fa);
b
}
fn void<'a, A: 'a>(fa: Self::F<'a, A>) -> Self::F<'a, ()> {
drop(fa);
}
}
impl Pure for SoloClass {
fn pure<'a, A: 'a>(a: A) -> Self::F<'a, A> {
a
}
}
impl ApplicativeSeq for SoloClass {
fn seq<'a, A: 'a, B: 'a>(
ff: Self::F<'a, impl 'a + FnOnce(A) -> B>,
fa: Self::F<'a, A>,
) -> Self::F<'a, B> {
ff(fa)
}
}
impl ApplicativeLA2 for SoloClass {
fn la2<'a, A: 'a, B: 'a, C: 'a>(
f: impl 'a + FnOnce(A, B) -> C,
fa: Self::F<'a, A>,
fb: Self::F<'a, B>,
) -> Self::F<'a, C> {
f(fa, fb)
}
}
impl ApplicativeTuple for SoloClass {
fn tuple<'a, A: 'a, B: 'a>((fa, fb): (Self::F<'a, A>, Self::F<'a, B>)) -> Self::F<'a, (A, B)>
where
Self: 'a,
{
(fa, fb)
}
}
impl Applicative for SoloClass {
fn discard_first<'a, A: 'a, B: 'a>(fa: Self::F<'a, A>, fb: Self::F<'a, B>) -> Self::F<'a, B> {
drop(fa);
fb
}
fn discard_second<'a, A: 'a, B: 'a>(fa: Self::F<'a, A>, fb: Self::F<'a, B>) -> Self::F<'a, A> {
drop(fb);
fa
}
}
impl Monad for SoloClass {
fn bind<'a, A: 'a, B: 'a>(
fa: Self::F<'a, A>,
f: impl 'a + FnOnce(A) -> Self::F<'a, B>,
) -> Self::F<'a, B> {
f(fa)
}
fn iterate_mut<'a, A: 'a, B: 'a>(
mut a: A,
mut f: impl 'a + FnMut(A) -> Self::F<'a, ControlFlow<B, A>>,
) -> Self::F<'a, B>
where
Self: 'a,
{
loop {
match f(a) {
ControlFlow::Continue(next_a) => a = next_a,
ControlFlow::Break(b) => return b,
};
}
}
fn iterate_argument<'a, A: 'a, B: 'a>(
mut a: A,
mut f: impl AIterative<'a, T = Self, A = A, B = B>,
) -> Self::F<'a, B>
where
Self: 'a,
{
loop {
match f.next(a) {
ControlFlow::Continue((new_a, new_f)) => (a, f) = (new_a, new_f),
ControlFlow::Break(b) => return b,
}
}
}
fn iterate<'a, B: 'a>(mut f: impl Iterative<'a, T = Self, B = B>) -> Self::F<'a, B>
where
Self: 'a,
{
loop {
match f.next() {
ControlFlow::Continue(next_f) => f = next_f,
ControlFlow::Break(b) => return b,
}
}
}
fn join<'a, A: 'a>(ffa: Self::F<'a, Self::F<'a, A>>) -> Self::F<'a, A> {
ffa
}
}
impl LocalFunctor for SoloClass {
fn unstuff<'a, A: 'a, B: 'a>(
state: Self::F<'a, ControlFlow<B, A>>,
) -> ControlFlow<Self::F<'a, B>, A>
where
Self: 'a,
{
state
}
fn stuff<'a, A: 'a, T: 'a + Pure>(fa: Self::F<'a, T::F<'a, A>>) -> T::F<'a, Self::F<'a, A>>
where
Self: 'a,
{
fa
}
}
impl Fail<std::convert::Infallible> for SoloClass {
fn fail<'a, A: 'a>(e: std::convert::Infallible) -> Self::F<'a, A>
where
Self: 'a,
std::convert::Infallible: 'a,
{
match e {}
}
}