Set

The Set class is a generic, type-safe implementation of a unique-value collection in PHP. It prevents duplicate values and maintains the order of insertion.

Purpose

This class provides a way to manage a set of unique items. It works similarly to JavaScript's Set object, offering operations like add, has, delete, and clear, while also ensuring type safety using PHPDoc generics.

Template Support

The class is declared with a generic template @template T, allowing you to enforce type consistency for the stored items. For example, a Set<string> will only accept string values.

Methods

• add(T $value): void
  Adds a value to the set if it does not already exist.
• has(T $value): bool
  Checks if the set contains the given value.
• delete(T $value): void
  Removes the specified value from the set.
• clear(): void
  Removes all values from the set.
• values(): T[]
  Returns an array of all values in the set, preserving insertion order.
• size(): int
  Returns the total number of values in the set.

Key Generation Logic

Internally, the class generates a unique key for each value to ensure uniqueness:

• Object: Uses spl_object_id to track unique instances.
• Array: Uses md5(serialize($value)) to create a hash key.
• Scalar: The scalar value itself is used as the key.

Example Usage

<?php
use Lib\Set;

$set = new Set();

$set->add('apple');
$set->add('banana');
$set->add('apple'); // Duplicate, won't be added

echo $set->has('banana') ? 'Yes' : 'No'; // Yes
echo $set->size(); // 2

$set->delete('banana');
print_r($set->values());

?>

For implementation details, refer to the file: src/Lib/Set.php.