organic/src/parser/list.rs
2022-12-10 22:04:39 -05:00

76 lines
1.8 KiB
Rust

use std::fmt::Debug;
use std::rc::Rc;
#[derive(Debug)]
pub struct List<T> {
head: Option<Rc<Node<T>>>,
}
impl<T> Clone for List<T> {
fn clone(&self) -> Self {
List {
head: self.head.clone(),
}
}
}
#[derive(Debug, Clone)]
pub struct Node<T> {
data: T,
parent: Option<Rc<Node<T>>>,
}
// TODO: This Debug is only needed because of the try_unwrap+expect
impl<T: Debug> List<T> {
pub fn new() -> Self {
List { head: None }
}
pub fn push_front(&self, data: T) -> List<T> {
List {
head: Some(Rc::new(Node {
data: data,
parent: self.head.clone(),
})),
}
}
pub fn pop_front(&mut self) -> (Option<T>, List<T>) {
match self.head.take() {
None => (None, List::new()),
Some(popped_node) => {
let extracted_node =
Rc::try_unwrap(popped_node).expect("TODO I should handle this better");
(
Some(extracted_node.data),
List {
head: extracted_node.parent,
},
)
}
}
}
pub fn without_front(&self) -> List<T> {
List {
head: self.head.as_ref().map(|node| node.parent.clone()).flatten(),
}
}
pub fn get_data(&self) -> Option<&T> {
self.head.as_ref().map(|rc_node| &rc_node.data)
}
pub fn is_empty(&self) -> bool {
self.head.is_none()
}
pub fn ptr_eq(&self, other: &List<T>) -> bool {
match (self.head.as_ref(), other.head.as_ref()) {
(None, None) => true,
(None, Some(_)) | (Some(_), None) => false,
(Some(me), Some(them)) => Rc::ptr_eq(me, them),
}
}
}