fix: allow inner loop traversals of SimpleCachingIteratorAggregate

[rela589n]

This PR adds consecutive caching to SimpleCachingIteratorAggregate allowing to traverse the same iterator within the loop without affecting outer iteration.

See #49

[what-the-diff]

PR Summary

• Update in Caching Mechanism
  At the core of the pull request are the changes made in the SimpleCachingIteratorAggregate.php file. This file has been updated to boost its efficiency when processing data. Specifically, it now does an additional check to continue its operations if it encounters the last data point in its memory. As part of this update, it includes a feature that allows it to keep track of previously processed data. This change will significantly enhance the system's performance by optimizing the data processing techniques.

• Enhancement in Test Procedures
  Alongside the above changes, this PR also enhances the capabilities of our testing procedures. A new testing method, aptly named testConsecutiveCachingFromInnerTraversals, has been added to the SimpleCachingIteratorAggregateTest.php file. This method is in place to verify that the updated data caching mechanism works accurately, especially when dealing with complex data structures. It helps ensure that our deliverables are reliable and efficient.

[drupol]

Thanks for your pull request, I will review it carefully as soon as I have a bit of time.

[drupol]

I've updated a bit the PR, do you think we could do something to avoid the if() in the foreach ?

[drupol]

I found a case where this PR would not be valid, here it is:

<?php

declare(strict_types=1);

namespace Issue49;

use Generator;
use loophp\iterators\SimpleCachingIteratorAggregate;

require __DIR__ . '/vendor/autoload.php';

$input = static function (): Generator {
    yield 'a' => 1;
    yield 'a' => 2;
    yield 'a' => 3;
    yield 'a' => 4;
    yield 'a' => 5;
    yield 'a' => 6;
};

$iter = new SimpleCachingIteratorAggregate($input());

foreach ($iter as $ko => $vo) {
    if ($ko === 2) {
        foreach ($iter as $ki => $vi) {
            var_dump("inner", $ki, $vi);
        }
    }

    var_dump("outer", $ko, $vo);
}

The issue lies in the fact that we rely on the value of the key. Since there can be multiple same keys in an iterator, we need to find another way to achieve this if you want this PR to be merged.

[github-actions]

Since this pull request has not had any activity within the last 5 days, I have marked it as stale.
I will close it if no further activity occurs within the next 5 days.

[rela589n]

I found a case where this PR would not be valid
...
The issue lies in the fact that we rely on the value of the key. Since there can be multiple same keys in an iterator, we need to find another way to achieve this if you want this PR to be merged.

I'm not sure what is the expected behavior thereon.

I have just added testSecondTraversalEliminatesDuplicatedKeys() that passes regardless of current-PR changes and generally represents how SimpleCachingIteratorAggregate deals with duplicated keys on consecutive traversals.

These two statements accurately represent it:

self::assertSame([
    ['a', 1],
    ['a', 2],
    ['a', 3],
], $firstIterationItems);

self::assertSame([
    ['a', 3],
], $secondIterationItems);

That being said, current logic of inner loop iterator traversal, looks expected to me:

public function testInnerTraversalConsumesDuplicatedKeyValues(): void
{
    $input = static function (): Generator {
        yield 'a' => 1;
        yield 'a' => 2;
        yield 'a' => 3;
        yield 'b' => 4;
        yield 'b' => 5;
    };

    $iter = new SimpleCachingIteratorAggregate($input());

    $outerItems = $innerItems = [];

    foreach ($iter as $ko => $vo) {
        if ($vo === 2) {
            foreach ($iter as $ki => $vi) {
                $innerItems[] = [$ki, $vi];
            }
        }

        $outerItems[] = [$ko, $vo];
    }

    self::assertSame([
        ['a', 1],
        ['a', 2],
        ['b', 5],
    ], $outerItems);

    self::assertSame([
        ['a', 2],
        ['a', 3],
        ['b', 4],
        ['b', 5],
    ], $innerItems);
}

Please, let me know what you think on this matter.

Thank you!

[github-actions]

Since this pull request has not had any activity within the last 5 days, I have marked it as stale.
I will close it if no further activity occurs within the next 5 days.

[rela589n]

Hi there!

Just in case you don't like the idea behind suggested changes or the implementation, please let me know so that current PR may be closed.

Thank you

[drupol]

Hi !

I haven't had the time to review it yet... This weekend with the Fosdem it's not going to be possible. Planning to do it next week hopefully!

I'll keep you posted, no worries.

Cheers.

[github-actions]

Since this pull request has not had any activity within the last 5 days, I have marked it as stale.
I will close it if no further activity occurs within the next 5 days.