Умножение свойств товара в настраиваемом поле атрибут корзины - [VM2&3] Управление товарами, атрибутами, типами, ценами

$basePriceShopCurrency = (substr($variant,0,1)=='+')?($basePriceShopCurrency + doubleval($variant)):($basePriceShopCurrency * doubleval($variant));

<?php
$a='20';
$b=5;
echo ($a*$b);//100
?>

<?php
$a=5;
$b='*20';
eval ("\$c =$a$b;");
echo $c;//100
?>

if(substr($variant,0,1)!=='*'){
$basePriceShopCurrency=$basePriceShopCurrency + doubleval($variant);
}else{
eval("\$basePriceShopCurrency=$basePriceShopCurrency$variant;");
}

eval("\$basePriceShopCurrency=$basePriceShopCurrency$variant;");

<?php
$a=5;
$b='20';
eval ("\$c =$a$b;");
echo $c;//520
?>

if (!empty($variant)) {
			  
                $basePriceShopCurrency=$basePriceShopCurrency + doubleval($variant);
        
		$prices['basePrice'] = $prices['basePriceVariant'] = $basePriceShopCurrency;

if (!empty($variant)) {		  
                eval("\$basePriceShopCurrency=$basePriceShopCurrency$variant;");
		$prices['basePrice'] = $prices['basePriceVariant'] = $basePriceShopCurrency;

первое поле:
500 мм : 0
350 мм : *14

			if(!empty($matches)){
				eval("\$basePriceShopCurrency=$basePriceShopCurrency$variant;");
				$this->productPrices['basePrice'] = $this->productPrices['basePriceVariant'] = $basePriceShopCurrency;
			}else{
				$basePriceShopCurrency = $basePriceShopCurrency + doubleval($variant);
				$this->productPrices['basePrice'] = $this->productPrices['basePriceVariant'] = $basePriceShopCurrency;
			}