New in Symfony 7.2: Expression Language Improvements

New ExpressionLanguage Operators

Contributed by Alexandre Daubois and HypeMC in #58052 and #58341

The ExpressionLanguage component already supports some binary operators: & (and), | (or) and ^ (xor). In Symfony 7.2, we're adding support for the rest of the bitwise operators: << (left shift), >> (right shift) and ~ (not).

These operators are not the most popular ones, but they come in handy in scenarios like dealing with bitfields inside expressions, such as the Yaml component flags:

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use Symfony\Component\ExpressionLanguage\ExpressionLanguage;

$el = new ExpressionLanguage();

$el->evaluate('1 << 4');  // result: 16
$el->evaluate('32 >> 4'); // result: 2
$el->evaluate('~5');      // result: -6

In addition, we're adding xor support as a logical operator (this operator was already available as a binary operator):

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$el->evaluate('$a xor $b');  // true if either $a or $b is true, but not both

Custom Provider Iterables

Contributed by HypeMC in #57685

The ExpressionLanguage component allows to extend its features with new functions thanks to custom expression providers. You can pass your providers via the second argument of the ExpressionLanguage service constructor.

This argument was a PHP array, so you couldn't use iterable variables (e.g. a tagged iterator). In Symfony 7.2, we're turning this array argument into an iterable argument, so you can use it as follows:

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app.my_expression_language:
    class: Symfony\Component\ExpressionLanguage\ExpressionLanguage
    arguments:
        $providers: !tagged_iterator app.my_custom_tag

Add Comment Support

Contributed by Valtteri R in #54978

Good configuration languages support comments. That's why, starting from Symfony 7.2, the ExpressionLanguage component will add support for single or multi-line comments with the syntax: /* this is a comment */. This will be helpful for example to explain certain magic values (e.g. those used in tests):

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// Before
$expression = "customer.group == 'vip_customers' or customer.id == 123";

// After
$expression = <<<EXPRESSION
    /* This expression checks that the purchase is made by
       a customer who doesn't belong to the regular users group */
    customer.group == 'vip_customers'
    or customer.id == 123 /* 123 is an internal test customer */
    EXPRESSION;