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#[cfg(feature = "fold")]
use crate::{Fold, FoldWith};
use serde::export::PhantomData;
use std::borrow::Cow;
pub trait CompilerPass {
fn name() -> Cow<'static, str>;
}
pub trait Repeated: CompilerPass {
fn changed(&self) -> bool;
fn reset(&mut self);
}
pub trait RepeatedPass<At>: Repeated + CompilerPass {}
impl<T, P> RepeatedPass<T> for P where P: CompilerPass + Repeated {}
#[derive(Debug, Copy, Clone)]
pub struct Repeat<P, At>
where
P: RepeatedPass<At>,
{
pass: P,
at: PhantomData<At>,
}
impl<P, At> Repeat<P, At>
where
P: RepeatedPass<At>,
{
pub fn new(pass: P) -> Self {
Self {
pass,
at: PhantomData,
}
}
}
impl<P, At> CompilerPass for Repeat<P, At>
where
P: RepeatedPass<At>,
{
fn name() -> Cow<'static, str> {
format!("Repeat({})", P::name()).into()
}
}
impl<P, At> Repeated for Repeat<P, At>
where
P: RepeatedPass<At>,
{
fn changed(&self) -> bool {
self.pass.changed()
}
fn reset(&mut self) {
self.pass.reset()
}
}
#[cfg(feature = "fold")]
impl<P, At> Fold<At> for Repeat<P, At>
where
At: FoldWith<Self> + FoldWith<P>,
P: RepeatedPass<At>,
{
fn fold(&mut self, mut node: At) -> At {
loop {
self.pass.reset();
node = node.fold_with(&mut self.pass);
if !self.pass.changed() {
break;
}
}
node
}
}