[−][src]Trait backtracking_iterator::BacktrackingIterator

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> { ... }
}

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

Associated Types

`type RefPoint`

The type used to refer to positions in the history

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Required methods

`fn get_ref_point(&self) -> Self::RefPoint`

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

`fn get_oldest_point(&self) -> Self::RefPoint`

Yield a reference to the oldest point in the history

`fn backtrack(&mut self, point: Self::RefPoint)`

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);

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Provided methods

`fn start_again(&mut self)`

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);

`fn peek(&mut self) -> Option<Self::Item>`

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);