Laravel 5+ password validation rules

PasswordValidator.php

<?php

namespace App\Validators;

class PasswordValidator
{
    public function validateLetters($attribute, $value)
    {
        return preg_match('/\pL/', $value);
    }

    public function validateNumbers($attribute, $value)
    {
        return preg_match('/\pN/', $value);
    }

    public function validateCaseDiff($attribute, $value)
    {
        return preg_match('/(\p{Ll}+.*\p{Lu})|(\p{Lu}+.*\p{Ll})/u', $value);
    }

    public function validateSymbols($attribute, $value)
    {
        return preg_match('/\p{Z}|\p{S}|\p{P}/', $value);
    }

}

validation.php

<?php

return [

//  ... add these to your validation translation file(s)

    "letters"                => "The :attribute must include at least one letter.",
    "case_diff"              => "The :attribute must include both upper and lower case letters.",
    "numbers"                => "The :attribute must include at least one number.",
    "symbols"                => "The :attribute must include at least one symbol.",
];

ValidationServiceProvider.php

<?php

namespace App\Providers;

use App;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\ServiceProvider;

class ValidationServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Validator::extend('case_diff', 'App\Validators\PasswordValidator@validateCaseDiff');
        Validator::extend('numbers', 'App\Validators\PasswordValidator@validateNumbers');
        Validator::extend('letters', 'App\Validators\PasswordValidator@validateLetters');
        Validator::extend('symbols', 'App\Validators\PasswordValidator@validateSymbols');
    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {

    }
}