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/*!
Documentation on the iterator DSL that some `konst::iter` macros support.
The macros from this crate don't directly invoke any of the method listed below,
they expand to equivalent code, this allows the macros to work on stable.
The [`collect_const`](crate::iter::collect_const) macro is
used in examples here purely for simplicity.
# Methods
Every iterator method below behaves the same as in the [`Iterator`] trait,
unless specified otherwise.
The methods listed alphabetically:
- [`copied`](#copied)
- [`enumerate`](#enumerate)
- [`filter_map`](#filter_map)
- [`filter`](#filter)
- [`flat_map`](#flat_map)
- [`flatten`](#flatten)
- [`map`](#map)
- [`rev`](#rev)
- [`skip_while`](#skip_while)
- [`skip`](#skip)
- [`take_while`](#take_while)
- [`take`](#take)
- [`zip`](#zip)
### `zip`
Limitation: the iterator DSL can't be passed as an argument to this method.
```rust
use konst::iter;
const ARR: [(&u8, usize); 4] =
iter::collect_const!((&u8, usize) => &[3u8, 5, 8, 13],zip(100..));
assert_eq!(ARR, [(&3, 100), (&5, 101), (&8, 102), (&13, 103)]);
```
### `enumerate`
`enumerate` always counts from `0`, regardless of whether the iterator is reversed.
```rust
use konst::iter;
const ARR: [(usize, &u8); 4] =
iter::collect_const!((usize, &u8) => &[3u8, 5, 8, 13],enumerate());
assert_eq!(ARR, [(0, &3), (1, &5), (2, &8), (3, &13)]);
```
### `filter`
```rust
use konst::iter;
const ARR: [&u8; 4] = iter::collect_const!(&u8 =>
&[3u8, 5, 8, 13, 21],
filter(|e| !e.is_power_of_two()),
);
assert_eq!(ARR, [&3, &5, &13, &21]);
```
### `map`
```rust
use konst::iter;
const ARR: [usize; 4] = iter::collect_const!(usize => (1..=4),map(|e| e * 3));
assert_eq!(ARR, [3, 6, 9, 12]);
```
### `filter_map`
```rust
use konst::iter;
use std::num::NonZeroU8;
const ARR: [NonZeroU8; 4] = iter::collect_const!(NonZeroU8 =>
&[3, 0, 1, 5, 6],
filter_map(|x| NonZeroU8::new(*x)),
);
assert_eq!(ARR, [3, 1, 5, 6].map(|n| NonZeroU8::new(n).unwrap()));
```
### `flat_map`
Limitation: the iterator DSL can't be passed as an argument to this method.
```rust
use konst::iter;
const ARR: [usize; 9] = iter::collect_const!(usize =>
&[3, 5, 8],
flat_map(|x| {
let x10 = *x * 10;
x10..x10 + 3
}),
);
assert_eq!(ARR, [30, 31, 32, 50, 51, 52, 80, 81, 82]);
```
### `flatten`
```rust
use konst::iter;
const ARR: [&u8; 4] =
iter::collect_const!(&u8 => &[&[3, 5], &[8, 13]], flatten());
assert_eq!(ARR, [&3, &5, &8, &13]);
```
### `copied`
```rust
use konst::iter;
const ARR: [u8; 3] = iter::collect_const!(u8 =>
&[2, 3, 4, 5, 6],
copied(),
filter(|n| *n % 2 == 0)
);
assert_eq!(ARR, [2, 4, 6]);
```
### `rev`
Limitation: iterator-reversing methods can't be called more than once in
the same macro invocation.
```rust
use konst::iter;
const ARR: [&u8; 3] = iter::collect_const!(&u8 => &[2, 3, 5],rev());
assert_eq!(ARR, [&5, &3, &2]);
```
### `take`
```rust
use konst::iter;
const ARR: [usize; 3] = iter::collect_const!(usize => 10..,take(3));
assert_eq!(ARR, [10, 11, 12]);
```
### `take_while`
```rust
use konst::iter;
const ARR: [&u8; 4] = iter::collect_const!(&u8 =>
&[3, 5, 8, 13, 21, 34, 55],take_while(|elem| **elem < 20 )
);
assert_eq!(ARR, [&3, &5, &8, &13]);
```
### `skip`
```rust
use konst::iter;
const ARR: [usize; 3] = iter::collect_const!(usize => 10..=15,skip(3));
assert_eq!(ARR, [13, 14, 15]);
```
### `skip_while`
```rust
use konst::iter;
const ARR: [&u8; 3] = iter::collect_const!(&u8 =>
&[3, 5, 8, 13, 21, 34, 55],skip_while(|elem| **elem < 20 )
);
assert_eq!(ARR, [&21, &34, &55]);
```
*/