[−][src]Crate peekmore
Synopsis:
This crate introduces a multi-peekable iterator.
The iterator is similar to Peekable. The main difference is that Peekable only
allows you to peek at the next element and no further. This crate aims to take that limitation
away.
A peek at how it works:
To enable peeking at multiple elements ahead of consuming a next element, the iterator uses a
traversable queue which holds the elements which you can peek at, but have not been
consumed (yet).
By default the underlying data structure of this queue is a Vec. By enabling the smallvec
feature, you can opt-in to use SmallVec as the underlying queue data structure. SmallVec uses
the stack for a limited amount of elements and will only allocate on the heap if this maximum
amount of elements is reached. SmallVec support for no_std is experimental and currently
requires a nightly compiler.
Illustrated example:
An illustrated example can be found at the PeekMoreIterator::peek documentation.
Usage example:
use peekmore::PeekMore; let iterable = [1, 2, 3, 4]; let mut iter = iterable.iter().peekmore(); // Peek at the first element. let v1 = iter.peek(); assert_eq!(v1, Some(&&1)); // Consume the first element. let v1c = iter.next(); assert_eq!(v1c, Some(&1)); // Peek at the second element (the element our cursor points at also moved to the second element, // since the first element was consumed.) let v2 = iter.peek(); assert_eq!(v2, Some(&&2)); // Advance the cursor. The cursor will now point to the third element. let _ = iter.move_next(); // Check that it is indeed at the third element. let v3 = iter.peek(); assert_eq!(v3, Some(&&3)); // Reset the position the cursor points at. The cursor will point to the first unconsumed element // again. iter.reset_view(); // Check that we are indeed at the second element again. let v2 = iter.peek(); assert_eq!(v2, Some(&&2)); // Shift the position of the cursor to the right twice by chaining the advance_view method. let _ = iter.move_next().move_next(); // Verify that the cursor indeed points at the fourth element. let v4 = iter.peek(); assert_eq!(v4, Some(&&4)); // Reset the position which the cursor points at again. iter.reset_view(); // We can also advance the cursor and peek with a single operation. let v3 = iter.peek_next(); assert_eq!(v3, Some(&&3));
Structs
| PeekMoreIterator | This iterator makes it possible to peek multiple times without consuming a value. In reality the underlying iterator will be consumed, but the values will be stored in a local queue. This queue allows us to move around unconsumed elements (as far as the iterator is concerned). |
Enums
| PeekMoreError | This enumeration provides errors which represent lack of success of the |
Traits
| PeekMore | Trait which allows you to create an iterator which allows us to peek at any unconsumed element. |