Trait backtracking_iterator::BacktrackingIterator

source · 
pub trait BacktrackingIterator: Iterator {
    type RefPoint;

    fn get_ref_point(&self) -> Self::RefPoint;
    fn get_oldest_point(&self) -> Self::RefPoint;
    fn backtrack(&mut self, point: Self::RefPoint);

    fn start_again(&mut self) { ... }
    fn peek(&mut self) -> Option<Self::Item> { ... }
}
Expand description

An iterator capable of backtracking behaviour This generifies the copying and non-copying versions and their behaviour

Required Associated Types

The type used to refer to positions in the history

Required Methods

Yield a reference to the current point in the history This reference must be valid for as long as the current point remains in the history

Yield a reference to the oldest point in the history

Return to a given point in the history Doesn’t have to do anything if the point is invalid

extern crate backtracking_iterator;
use backtracking_iterator::{BacktrackingIterator, Walkback, Walkbackable};

let v = vec![1_u8, 2_u8, 3_u8];
let mut rec = backtracking_iterator::BacktrackingRecorder::new(v.into_iter());
let mut bt = rec.copying();
bt.next(); // 1_u8
bt.next(); // 2_u8
let wb_pos = {
  let mut wb = bt.walk_back();
  assert!(wb.next().unwrap() == 2_u8);
  wb.get_ref_point()
};
 
bt.backtrack(wb_pos);
assert!(bt.next().unwrap() == 2_u8);

Provided Methods

Start the iterator again from all the elements in the current history The iterator will repeat every element which was emitted since the last call to forget().

extern crate backtracking_iterator;
use backtracking_iterator::BacktrackingIterator;

let v = vec![1_u8, 2_u8];
let mut rec = backtracking_iterator::BacktrackingRecorder::new(v.into_iter());
let mut bt = rec.copying();
bt.next();
bt.start_again();
assert!(bt.next().unwrap() == 1_u8);

Get the next element of the iterator, without advancing it. The iterator will yield the same element again in the next call to peek() or next().

extern crate backtracking_iterator;
use backtracking_iterator::BacktrackingIterator;

let v = vec![1_u8, 2_u8];
let mut rec = backtracking_iterator::BacktrackingRecorder::new(v.into_iter());
let mut bt = rec.copying();
assert!(bt.peek().unwrap() == 1_u8);
assert!(bt.peek().unwrap() == 1_u8);
assert!(bt.peek().unwrap() == 1_u8);
assert!(bt.next().unwrap() == 1_u8);

Implementors