ArrayView::join and FixedArray::join

[ethereal-dream]

Adding ArrayView::join and FixedArray::join functions makes it convenient to concatenate strings within an array into a single complete string.

[peter-jerry-ye-code-review]

Duplicate implementation of join logic in both View::join and FixedArray::join

Category
Maintainability
Code Snippet
Both View::join and FixedArray::join implement similar string joining logic
Recommendation
Extract the common join logic into a private helper function that can be used by both implementations
Reasoning
The current implementation duplicates the size calculation and string building logic. A shared implementation would reduce code duplication and make future maintenance easier

Size hint calculation could be more accurate

Category
Performance
Code Snippet
size_hint = size_hint << 1 // in View::join
Recommendation
Remove the doubling of size_hint as the calculation already accounts for all string lengths and separators
Reasoning
The current implementation doubles the calculated size hint which may lead to unnecessary memory allocation. The size hint calculation already includes all string lengths and separator lengths

Inconsistent separator handling between empty and non-empty cases

Category
Correctness
Code Snippet
if separator is "" vs if separator.is_empty()
Recommendation
Use consistent empty check with separator.is_empty() across all implementations
Reasoning
View::join uses 'is ""' while FixedArray::join uses 'is_empty()'. Using consistent method calls makes the code more maintainable and prevents potential bugs if string comparison behavior changes

[coveralls]

Pull Request Test Coverage Report for Build 6960

Details

• 28 of 28 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 92.498%

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Totals
Change from base Build 6956:	0.01%
Covered Lines:	8730
Relevant Lines:	9438

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💛 - Coveralls

[peter-jerry-ye]

@Yu-zh asked whether we should be using View instead of String.

I think maybe we can use @string.View for separator, but keep T[String] for this signature.

[ethereal-dream]

When using @string.View for separator, what should I do with string.write_string(separator) since there doesn't seem to be a write_view function?

[peter-jerry-ye]

I think you can simply call to_string on the view. The support for view on the string builder would come later as its currently blocked by how the core package is organize, which I assume would still need a few weeks.