IPV6BadChar example

if ($prev->isA(EmailLexer::S_COLON)) {
            $this->warnings[IPV6ColonEnd::CODE] = new IPV6ColonEnd();
        }

        $IPv6       = substr($addressLiteral, 5);
        //Daniel Marschall's new IPv6 testing strategy         $matchesIP  = explode(':', $IPv6);
        $groupCount = count($matchesIP);
        $colons     = strpos($IPv6, '::');

        if (count(preg_grep('/^[0-9A-Fa-f]{0,4}$/', $matchesIP, PREG_GREP_INVERT)) !== 0) {
            $this->warnings[IPV6BadChar::CODE] = new IPV6BadChar();
        }

        if ($colons === false) {
            // We need exactly the right number of groups             if ($groupCount !== $maxGroups) {
                $this->warnings[IPV6GroupCount::CODE] = new IPV6GroupCount();
            }
            return;
        }

        if ($colons !== strrpos($IPv6, '::')) {