perf(deque): use @deque.iter[2]() for @deque.each[i]()

[rami3l]

Continuation of #1354.

Summary

Improvements to iteration methods:

• pub fn each[A](self : T[A], f : (A) -> Unit) -> Unit: Updated the method to use a direct iteration over the collection instead of indexing.
• pub fn eachi[A](self : T[A], f : (Int, A) -> Unit) -> Unit: Updated the method to use a direct iteration with index over the collection instead of indexing.

[coveralls]

Pull Request Test Coverage Report for Build 4306

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.006%) to 81.248%

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Totals
Change from base Build 4303:	-0.006%
Covered Lines:	4623
Relevant Lines:	5690

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💛 - Coveralls

[peter-jerry-ye-code-review]

‼️ This code review is generated by a bot. Please verify the content before trusting it.

The provided git diff output shows changes to a deque implementation, specifically in the each and eachi functions. Here are three potential issues or improvements that can be observed:

1. Inconsistent Loop Syntax:

   • The original code uses a traditional for loop with an index (for i = 0; i < self.length(); i = i + 1), while the updated code uses a more idiomatic iterator-based loop (for v in self and for i, v in self).
   • Potential Problem: If the self type does not implement the necessary iterator protocol (e.g., Iterator or IntoIterator), the new syntax will not work. Ensure that T[A] implements the appropriate iterator traits.

2. Potential Performance Issue:

   • The original code explicitly calls self.length() in each iteration of the loop, which is fine if self.length() is a constant-time operation. However, the new code relies on the iterator protocol, which might be less efficient if the iterator does not optimize for performance.
   • Potential Problem: If the iterator is not optimized, this could lead to a performance regression. Ensure that the iterator implementation is efficient.

3. Typo in Comment:

   • In the eachi function, the comment mentions idx_sum but does not provide a clear explanation of what idx_sum represents.
   • Potential Problem: This could confuse readers of the code. Consider updating the comment to provide more context or an example of what idx_sum is supposed to represent.

These are the three main observations based on the provided diff.