Thanks a bunch! Your updated code is indeed amazing, for its level of detail and re-usable tokens. It just gives a greater level of control and granularity over matching schema without having to resort to a code that looks like hieroglyphics.

In hindsight, it was silly of me to ask again without checking the grammar. The last 3 rules failing is no surprise since the grammar doesn't account for it yet. I should produce a complete code soon, for the sake of others looking for the same stuff.

May I ask whether it is possible to code multi-line grammar also in to regex? For e.g the below section of config file

object-group network NOC-NC-NC1
 network-object 192.162.137.0 255.255.255.0
 network-object 192.162.146.0 255.255.255.0
object-group network NOC-NC-NC2
 network-object 192.162.131.0 255.255.255.0
 network-object 192.162.134.0 255.255.255.0
[download]

Should be read into a hash of arrays as:

$object_hash{"NOC-NC-NC1"} => ["192.162.137.0 255.255.255.0","192.162.
+146.0 255.255.255.0"]
$object_hash{"NOC-NC-NC2"} => ["192.162.131.0 255.255.255.0","192.162.
+134.0 255.255.255.0"]
[download]