exercism-php/allergies/Allergies.php

<?php

/*
 * By adding type hints and enabling strict type checking, code can become
 * easier to read, self-documenting and reduce the number of potential bugs.
 * By default, type declarations are non-strict, which means they will attempt
 * to change the original type to match the type specified by the
 * type-declaration.
 *
 * In other words, if you pass a string to a function requiring a float,
 * it will attempt to convert the string value to a float.
 *
 * To enable strict mode, a single declare directive must be placed at the top
 * of the file.
 * This means that the strictness of typing is configured on a per-file basis.
 * This directive not only affects the type declarations of parameters, but also
 * a function's return type.
 *
 * For more info review the Concept on strict type checking in the PHP track
 * <link>.
 *
 * To disable strict typing, comment out the directive below.
 */

declare(strict_types=1);

class Allergies {

  /**
   * @var \Allergen[]
   */
  private array $allergies = [];

  public function __construct(int $score) {
    $score &= Allergen::CATS * 2 - 1;
    $id = Allergen::EGGS;
    while ($id <= Allergen::CATS) {
      if ($id & $score) {
        $this->allergies[] = new Allergen($id);
      }
      $id <<= 1;
    }
  }

  public function isAllergicTo(Allergen $allergen): bool {
    return in_array($allergen, $this->allergies);
  }

  /**
   * @return \Allergen[]
   */
  public function getList(): array {
    return $this->allergies;
  }

}

class Allergen {

  public const EGGS = 1;

  public const PEANUTS = 2;

  public const SHELLFISH = 4;

  public const STRAWBERRIES = 8;

  public const TOMATOES = 16;

  public const CHOCOLATE = 32;

  public const POLLEN = 64;

  public const CATS = 128;

  private int $id;

  public function __construct(int $id) {
    $this->id = $id;
  }

  public static function allergenList(): array {
    return [];
  }

  public function getScore(): int {
    return $this->id;
  }
}