README.md

PHP Expression Language based on TWIG

This library provides interfaces for safe evaluate expressions, compile them to native PHP code for performance.

Purpose

It is an alternative to the Symfony Expression Language which allows more operations such as for if etc. You can to implement any logic and execute it safely and quickly. We removed PRINT_TOKEN TEXT_TOKEN from TWIG AST-tree to prevent output, added return statement and made a more improvement.

Features

• Allow to execution scripts and evaluate expressions.
• Debugging with PhpStorm twig debugger feature.
• Support all twig features, like sandbox, custom extension, tokens, functions.
• Minimum performance overhead - faster that twig.
• Syntax highlighting is already built into the most popular IDEs.

Example Usage

Base evaluate Example

$lang = new TwigLanguage(options: ['cache' => __DIR__ . '/var/cache/twig']);
$context = ['var1' => 10, 'users' => [1, 2, 5], 'user' => 1];

$lang->evaluate('user in users ? users|length + 1 : var1')

Execute Script

{% set msg = 'New sms' %}
{% set newUsers = '' %}
{% set usersList = [] %}
{% set lastUserId = redis_get('sms-user') %} # redis_get - custom function

{% for user in users %}
    {% if user > lastUserId %}
        {% set newUsers = newUsers ~ user ~ ' ' %}
        {% do redis_set('sms-user', user, 0) %}
        {% set usersList[_key] = user %} # allow set to array 
    {% endif %}
{% endfor %}

{% if newUsers is not empty %}
    {% do telegram_send('chart111', msg ~ "\n" ~ newUsers|trim) %} # telegram_send - custom function
{% endif %}

{% return usersList %} # new return token 

$lang = new TwigLanguage();
$script = <<<TXT
...
{% return 10 + 15 %}
TXT;

var_dump($lang->execute($script, $context));

// execute with template 
$loader = new \Twig\Loader\FilesystemLoader(__DIR__ . '/scripts');
$lang = new TwigLanguage(loader: $loader);
var_dump($lang->execute('test22.twig', $context));

evaluate method - is faster than execute, because we skip additional exception handling and error logic. Also evaluate - accept code without {% token.

Benchmark Test

We use next the test to compare overhead between Symfony Expression Language and this library

$lang = new TwigLanguage(options: [
    'cache' => __DIR__ . '/var/cache/twig',
    'auto_reload' => true,
]);


$expr = 'user == 1 ? var1 + var2 : var1 + 1';
$lang->evaluate($expr, $context);

// Symfony EL 
$sf = new ExpressionLanguage();
$expression = $sf->parse($expr, array_keys($context));
$sf->evaluate($expression, $context);

// Native PHP

$fn = static function ($context) {
    return $context['user'] === 1 ? $context['var1'] + $context['var2'] : $context['var1'] + 1;
};

$t1 = microtime(true);
for ($i = 0; $i < 200000; $i++) {
    // comment line where needed
    $result = $fn($context);
    $result = $sf->evaluate($expression, $context);
    $result = $lang->evaluate($expr, $context);
}

echo (microtime(true) - $t1)/200000 * 1000000 . "\n";

Extends and sandbox mode.

See Twig documentation

Result

Lang	Op. Time	Overhead cost
Native PHP	0.058µs	0%
Symfony EL	0.461µs	+800%
Twig lang	0.187µs	+300%

License

MIT License.