Implements new spread instruction

[alsonleej]

Description

Type of change

Deals with #1650

• New feature (non-breaking change which adds functionality)

How to test

const f = (...x) => x;

// one spread
// f(...[1, 2, 3]);

// empty array spread
// f(...[]);

// literals, empty array, multiple spreads
// f(0, ...[1, 2], ...[3, 4], ...[], ...[6], 7);

// array reference
// const rr = [1,2,3];
// f(...rr, 3);

// function returning array
// const k = () => [1, 2, 3];
// const g = (...x) => x;
// g(...k()); // Expected: [1, 2, 3]

Checklist

• I have tested this code

TO-DO: run time check if RHS of spread operator is indeed an array

[martin-henz]

TO-DO: run time check if RHS of spread operator is indeed an array

What happens if the RHS of spread is not an array? Can you try:

math_max(... 1);

[martin-henz]

...because spread in arrays is currently not allowed in Source.

[martin-henz]

Looks good!

[coveralls]

Pull Request Test Coverage Report for Build 13545721578

Details

• 8 of 20 (40.0%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 81.596%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/cse-machine/interpreter.ts	1	13	7.69%

Totals
Change from base Build 13432508686:	-0.06%
Covered Lines:	11473
Relevant Lines:	13674

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💛 - Coveralls