feat(corelib): core::iter::zip

[julio4]

pub fn zip<A, B>(a: A, b: B) -> Zip<A, B>

Converts the arguments to iterators and zips them.

Examples

use core::iter::zip;

let xs = array![1, 2, 3];
let ys = array![4, 5, 6];

let mut iter = zip(xs, ys);

assert_eq!(iter.next(), Option::Some((1, 4)));
assert_eq!(iter.next(), Option::Some((2, 5)));
assert_eq!(iter.next(), Option::Some((3, 6)));
assert_eq!(iter.next(), Option::None);

// Nested zips are also possible:
let xs = array![1, 2, 3];
let ys = array![4, 5, 6];
let zs = array![7, 8, 9];

let mut iter = zip(zip(xs, ys), zs);

assert_eq!(iter.next(), Option::Some(((1, 4), 7)));
assert_eq!(iter.next(), Option::Some(((2, 5), 8)));
assert_eq!(iter.next(), Option::Some(((3, 6), 9)));
assert_eq!(iter.next(), Option::None);

[reviewable-StarkWare]

This change is 

[orizi]

Reviewed 3 of 4 files at r1, all commit messages.
Reviewable status: 3 of 4 files reviewed, 2 unresolved discussions (waiting on @julio4)

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corelib/src/iter/adapters/zip_adapter.cairo line 70 at r1 (raw file):

    +Destruct<IB>,
> of Iterator<Zip<A, B>> {
    type Item = (IA, IB);

probably preferable:

Suggestion:

impl ZipIterator<
    A,
    B,
    impl IterA: Iterator<A>,
    impl IterB: Iterator<B>,
    +Destruct<A>,
    +Destruct<B>,
    +Destruct<IterA::Item>,
    +Destruct<IterB::Item>,
> of Iterator<Zip<A, B>> {
    type Item = (IterA::Item, IterB::Item);

---

corelib/src/test/iter_test.cairo line 25 at r1 (raw file):

    assert_eq!(iter.next(), Option::Some(((2, 5), 8)));
    assert_eq!(iter.next(), Option::Some(((3, 6), 9)));
    assert_eq!(iter.next(), Option::None);

Suggestion:

    let mut iter = zip(array![1, 2, 3], array![4, 5, 6]);

    assert_eq!(iter.next(), Option::Some((1, 4)));
    assert_eq!(iter.next(), Option::Some((2, 5)));
    assert_eq!(iter.next(), Option::Some((3, 6)));
    assert_eq!(iter.next(), Option::None);

    // Nested zips are also possible:
    let mut iter = zip(zip(array![1, 2, 3], array![4, 5, 6]), array![7, 8, 9]);

    assert_eq!(iter.next(), Option::Some(((1, 4), 7)));
    assert_eq!(iter.next(), Option::Some(((2, 5), 8)));
    assert_eq!(iter.next(), Option::Some(((3, 6), 9)));
    assert_eq!(iter.next(), Option::None);

[orizi]

Reviewable status: 3 of 4 files reviewed, 3 unresolved discussions (waiting on @julio4)

---

corelib/src/iter/adapters/zip_adapter.cairo line 36 at r1 (raw file):

/// let zs = array![7, 8, 9];
///
/// let mut iter = zip(zip(xs, ys), zs);

inline arrays - same as in test.

Code quote:

/// let xs = array![1, 2, 3];
/// let ys = array![4, 5, 6];
///
/// let mut iter = zip(xs, ys);
///
/// assert_eq!(iter.next(), Option::Some((1, 4)));
/// assert_eq!(iter.next(), Option::Some((2, 5)));
/// assert_eq!(iter.next(), Option::Some((3, 6)));
/// assert_eq!(iter.next(), Option::None);
///
/// // Nested zips are also possible:
/// let xs = array![1, 2, 3];
/// let ys = array![4, 5, 6];
/// let zs = array![7, 8, 9];
///
/// let mut iter = zip(zip(xs, ys), zs);

[orizi]

Reviewable status: 3 of 4 files reviewed, 3 unresolved discussions (waiting on @julio4)

---

a discussion (no related file):
@TomerStarkware for 2nd eye

[enitrat]

Reviewable status: 3 of 4 files reviewed, 4 unresolved discussions (waiting on @julio4 and @orizi)

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corelib/src/iter/adapters/zip_adapter.cairo line 15 at r1 (raw file):

/// Converts the arguments to iterators and zips them.
///

You can pre-emptively link this to [Iterator::zip] as I guess that's going to come next

Code snippet:

/// See the documentation of [`Iterator::zip`] for more.

[julio4]

Reviewable status: 3 of 4 files reviewed, 4 unresolved discussions (waiting on @enitrat and @orizi)

---

corelib/src/iter/adapters/zip_adapter.cairo line 36 at r1 (raw file):

Previously, orizi wrote…

inline arrays - same as in test.

Done.
However I would argue that it's a bit more readable without inlining, especially for nested zip, and it could make sense to make it as readable as possible in the documentation.

---

corelib/src/iter/adapters/zip_adapter.cairo line 70 at r1 (raw file):

Previously, orizi wrote…

probably preferable:

Done.

---

corelib/src/test/iter_test.cairo line 25 at r1 (raw file):

    assert_eq!(iter.next(), Option::Some(((2, 5), 8)));
    assert_eq!(iter.next(), Option::Some(((3, 6), 9)));
    assert_eq!(iter.next(), Option::None);

Done.

[julio4]

Reviewable status: 2 of 4 files reviewed, 4 unresolved discussions (waiting on @enitrat and @orizi)

---

corelib/src/iter/adapters/zip_adapter.cairo line 15 at r1 (raw file):

Previously, enitrat (Mathieu) wrote…

You can pre-emptively link this to [Iterator::zip] as I guess that's going to come next

There's still some issue with default impl so I prefer not blocking thing and I'll add in a separate PR