#iterator #macro #iter

ad-hoc-iter

Ad-hoc exact size owning iterator macro and other optional utils

6 releases

0.2.3 Dec 30, 2020
0.2.2 Nov 10, 2020
0.1.1 Nov 9, 2020

#647 in Rust patterns

37 downloads per month

MIT license

15KB
335 lines

Ad-hoc owning iterator types

This crate defines the macro iter! which produces ad-hoc iterator types that own their values and have compile-time known exact sizes.

Usage

This macro can be used exactly like vec!, except it produces an impl Iterator that does not allocate. This impl Iterator yields the values directly, not references to the values.

This can be useful for when you want a ad-hoc iterator of a non-copy type, as sized slices and arrays currently do not implement IntoIterator in a way that moves their values, instead they yield references, causing the need for cloning.

The iter! macro's iterator types move their values on calls to next() instead of returning references, and drop the non-consumed values when the iterator is dropped itself.

Example

Concatenating a 'slice' of String without cloning.

let whole: String = iter![String::from("Hell"),
			  String::from("o "),
			  String::from("world"),
			  String::from("!")]
    .collect();
assert_eq!("Hello world!", &whole[..]);

Functions

The iterator types also have a few associated functions.

The length of the whole iterator

pub const fn len(&self) -> usize

The rest of the iterator that has not been consumed.

pub fn rest(&self) -> &[T]

The whole array.

All values that have not been consumed are initialised, values that have been consumed are uninitialised.

pub fn array(&self) -> &[MaybeUninit<T>; Self::LEN]

How many items have since been consumed.

pub const fn consumed(&self) -> usize

License

MIT

No runtime deps

Features

  • maybe-many