如何在Smarty中编写PHP语法？

I want to know how to write php syntax in smarty template(.tpl).

For example I'm using below php syntax in Pure Codeigniter(No Smarty include) and it's working perfectly.

<?= isset($value) ? $value['phone'] : '' ?>

But in Smarty, It's not work. How should write this? Please suggest me.

Try this:

{if isset($value)}
    $value['phone']
{/if}

years ago I used:

{php}
// php code
{/php}

Nowadays I don't know if it still works