Doctrine\MongoDB\Aggregation\Stage\Operator::toUpper PHP Method

The argument can be any expression as long as it resolves to a string.

See also: http://docs.mongodb.org/manual/reference/operator/aggregation/toUpper/

See also: Expr::toUpper

public toUpper ( mixed \| Expr $expression )
$expression	mixed \| Doctrine\MongoDB\Aggregation\Expr

    public function toUpper($expression)
    {
        $this->expr->toUpper($expression);
        return $this;
    }

Operator