public function check_for_matches( $stackPtr ) {
		$token_content = strtolower( $this->tokens[ $stackPtr ]['content'] );
		$skip_to       = array();

		foreach ( $this->groups as $groupName => $group ) {

			if ( isset( $this->excluded_groups[ $groupName ] ) ) {
				continue;
			}

			if ( isset( $group['whitelist'][ $token_content ] ) ) {
				continue;
			}

			if ( preg_match( $group['regex'], $token_content ) === 1 ) {
				$skip_to[] = $this->process_matched_token( $stackPtr, $groupName, $token_content );
			}
		}

		if ( empty( $skip_to ) || min( $skip_to ) === 0 ) {
			return;
		}

		return min( $skip_to );
	}