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use super::types::Entry;
use crate::types::{HasIx, Ix};
pub trait Strategy<T: 'static, State> {
fn run<'a, F, V>(&self, get_next: &mut F, visitor: &mut V, start: Entry<T>)
where
F: FnMut(Ix<T>) -> Option<Entry<'a, T>>,
V: Visitor<T, State>;
}
pub trait Visitor<T, State> {
fn visit(&mut self, st: State, e: Entry<T>);
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum PreAndPost {
Pre,
Post,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum PreOnly {
Pre,
}
pub struct PrePostVisitor<Pre, Post> {
pub pre: Pre,
pub post: Post,
}
impl<Pre, Post, T> Visitor<T, PreAndPost> for PrePostVisitor<Pre, Post>
where
Pre: FnMut(Entry<T>),
Post: FnMut(Entry<T>),
{
fn visit(&mut self, st: PreAndPost, e: Entry<T>) {
match st {
PreAndPost::Pre => (self.pre)(e),
PreAndPost::Post => (self.post)(e),
}
}
}
impl<Pre, Post, T> Visitor<T, PreOnly> for PrePostVisitor<Pre, Post>
where
Pre: FnMut(Entry<T>),
{
fn visit(&mut self, st: PreOnly, e: Entry<T>) {
match st {
PreOnly::Pre => (self.pre)(e),
}
}
}
#[derive(Clone, Copy, PartialEq, Eq)]
pub struct CallStack;
impl<T: 'static + HasIx<T>> Strategy<T, PreAndPost> for CallStack {
fn run<'a, F, V>(&self, get_next: &mut F, visitor: &mut V, mut next: Entry<T>)
where
F: FnMut(Ix<T>) -> Option<Entry<'a, T>>,
V: Visitor<T, PreAndPost>,
{
visitor.visit(PreAndPost::Pre, next.reborrow());
next.get_mut().foreach_ix(|ix| {
if let Some(next) = get_next(*ix) {
self.run(get_next, visitor, next);
}
});
visitor.visit(PreAndPost::Post, next.reborrow());
}
}
impl<T: 'static + HasIx<T>> Strategy<T, PreOnly> for CallStack {
fn run<'a, F, V>(&self, get_next: &mut F, visitor: &mut V, mut next: Entry<T>)
where
F: FnMut(Ix<T>) -> Option<Entry<'a, T>>,
V: Visitor<T, PreOnly>,
{
visitor.visit(PreOnly::Pre, next.reborrow());
next.get_mut().foreach_ix(|ix| {
if let Some(next) = get_next(*ix) {
self.run(get_next, visitor, next);
}
});
}
}
impl<T: 'static + HasIx<T>, St, Str: Strategy<T, St>> Strategy<T, St> for &Str {
fn run<'a, F, V>(&self, get_next: &mut F, visitor: &mut V, start: Entry<T>)
where
F: FnMut(Ix<T>) -> Option<Entry<'a, T>>,
V: Visitor<T, St>,
{
<Str as Strategy<_, _>>::run(*self, get_next, visitor, start);
}
}
pub(crate) fn no_process<T>(_: Entry<T>) {}