php - How to use backreference in preg_replace() as object property?

I have the following PHP code:

$items = json_decode('[
    {"title":"Title #1", "text":"Text #1"},
    {"title":"Title #2", "text":"Text #2"}
]');

$itemTmpl = "<h3 class='foo'>{title}</h3><div class='bar'>{text}</div>";

$html = [];
foreach($items as $item) {
    $html[] = preg_replace("/\{[a-z]+\}/", $item->{$1}, $itemTmpl);
}
    
echo implode("\n", $html);

As you see, I'm trying to use backreference as object property in order to replace variables like {title} and {text} with data from the array expecting $item->{'title'} and $item->{'text'}.

But the current code throws the error

syntax error, unexpected '1' (T_LNUMBER), expecting variable (T_VARIABLE) or '{' or '$' in ...

How to resolve the issue?

Answer

Solution:

There will be several ways to do this; I'll demonstrate just one way.

iterate over your decoded items,
Replace each placeholder by accessing the key of the given item using the text captured from between the curly braces

Code: (Demo)

$html = [];
foreach ($items as $item) {
    $html[] = preg_replace_callback(
        '/{([a-z]+)}/',
        fn($m) => $item->{$m[1]},
        $itemTmpl
    );
}
var_export($html);

Source