Forms and validation

The field

use Tilttek\DiceBundle\Infrastructure\Form\DiceExpressionType;

$builder->add('expression', DiceExpressionType::class, ['locale' => $request->getLocale()]);

DiceExpressionType is a text field whose data is the text as typed, checked by the DiceExpression constraint in the notation of locale — the canonical one when it is null —, with the spelling checker off.

The constraint

use Tilttek\DiceBundle\Infrastructure\Validator\DiceExpression;

#[DiceExpression(locale: 'de')]
public string $expression;

The value passes when it parses within the limits; null and the empty string pass, as with every constraint but NotBlank. The violation's message is This is not a dice expression: {{ reason }}, the reason being the library's message with the position of the error; its code is DiceExpression::INVALID. message replaces the text.