- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$vals = array(
"[[aa]]",
"/\\/\\",
"&",
"$^",
);
$rx = '/^[-+=_.:;!?@#$%&*<>^"\'\\\\\\/\\(\\)\\[\\]\\{\\}a-z0-9]+$/i';
foreach ($vals as $v) {
var_dump(preg_match($rx, $v));
}