A Better Peekable

This crate provides a trait BetterPeekable and a type BPeekable<I: Iterator> which is a wrapper over an iterator and returned by calling better_peekable() on any Iterator. Which implies that you can call the usual iterator methods on BPeekable<I> like next(). You can now also call size_hint and DoubleEndedIterator like rposition and similar methods at the time of this version 0.2.2 in addition to peek and peek_n which allow you to peek the inner iterator without consuming it. peek gives you a reference to the immediately available item to be consumed by a next() call, whereas peek_n allows you to peek n times ahead. Calling peek_n(0) is the same as calling peek.

peek and peek_n are idempotent which means calling them repeatedly on BPeekable should have no effects on the underlying iterator or any state of BPeekable. If you find a bug that violates this contract, please open an issue.

Usage

Add to better_peekable to your Cargo.toml.

toml [dependencies] better_peekable = "0.2.2"

We are going to test the idempotence of BPeekable using the following sequence of peek and peek_n calls.

```rust // Required for peek and peekn use betterpeekable::BetterPeekable;

fn main() { let vec = vec![ String::from("Hello"), String::from("World"), String::from("It's a nice day to make"), String::from("A better peekable iterator adaptor"), String::from("Peek_N and Peek are supposed to be"), String::from("Idempotent Methods"), ];

    let mut iter = vec.into_iter();
    let mut better_peeker = iter.better_peekable();

    assert_eq!(better_peeker.peek(), Some(&"Hello".to_string()));
    assert_eq!(better_peeker.peek(), Some(&"Hello".to_string()));
    assert_eq!(better_peeker.peek(), Some(&"Hello".to_string()));
    assert_eq!(better_peeker.peek_n(1), Some(&"World".to_string()));
    assert_eq!(better_peeker.next(), Some("Hello".to_string()));
    assert_eq!(better_peeker.next(), Some("World".to_string()));
    assert_eq!(
        better_peeker.peek(),
        Some(&"It's a nice day to make".to_string())
    );
    assert_eq!(
        better_peeker.peek_n(0),
        Some(&"It's a nice day to make".to_string())
    );
    assert_eq!(
        better_peeker.peek_n(1),
        Some(&"A better peekable iterator adaptor".to_string())
    );
    assert_eq!(
        better_peeker.nth(1),
        Some("A better peekable iterator adaptor".to_string())
    );
    assert_eq!(
        better_peeker.peek_n(1),
        Some(&"Idempotent Methods".to_string())
    );

```