+ /** regexp:
+ * \$ literal $
+ * (\[)? optional open square bracket
+ * ([a-zA-Z0-9-_]+\.?)+ var name, followed by optional
+ * dot, repeated at least 1 time
+ * (?(1)\]) if there was opened square bracket
+ * (subgrup 1), match close bracket
+ */
+ if (preg_match_all('/\$(\[)?([a-zA-Z0-9-_]+\.?)+(?(1)\])/', $s,$m)){
+