How to compose a regexp?

Question

Regular Expressions

You need to get what's inside the brackets, or rather "param" if $content contains or

$content = 'Test ';
$pattern = '@\[\[\$(.+?)\]\]@si';
if (preg_match($pattern, $content, $matches) > 0) {
 $tag = $matches[0];
}

Answer 1

/\[\[!?\$(.*)\]\]/