feat(corelib): range IndexView

[cairoIover]

Adds IndexView to Array and Span, enabling the following syntax:
assert_eq!(arr[2_usize..4] == [3, 4].span());

[reviewable-StarkWare]

This change is 

[cairoIover]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion

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corelib/src/test/array_test.cairo line 15 at r1 (raw file):

fn test_array_out_of_bound_1() {
    let arr = array![10, 11, 12];
    arr[3_usize];

@orizi there's an issue with type inference that forced me to specify that this index is a usize. Would you be able to TAL?

Code quote:

    arr[3_usize];

[orizi]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @cairoIover and @orizi)

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corelib/src/test/array_test.cairo line 15 at r1 (raw file):

Previously, cairoIover wrote…

@orizi there's an issue with type inference that forced me to specify that this index is a usize. Would you be able to TAL?

this is the first instance where we have 2 options for an Index index type - we need to find the exact culprit.

I'd postpone this PR now - as .slice(...) already exists.

[cairoIover]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @orizi)

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corelib/src/test/array_test.cairo line 15 at r1 (raw file):

Previously, orizi wrote…

this is the first instance where we have 2 options for an Index index type - we need to find the exact culprit.

I'd postpone this PR now - as .slice(...) already exists.

Sure - I'll keep this open until then. Just so that I know is it something you plan on investigating in the near future?

[orizi]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @cairoIover and @orizi)

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corelib/src/test/array_test.cairo line 15 at r1 (raw file):

Previously, cairoIover wrote…

Sure - I'll keep this open until then. Just so that I know is it something you plan on investigating in the near future?

i hope to.
but i'm yet to be sure we will have a proper solution any time soon (because it really depends on the exact cause of the problem)