(?x:	\(  # match the initial opening parenthesis	# Now make a named group 'balanced' which matches	# a balanced substring.	(?<balanced>		# A balanced substring is either something that is not a parenthesis:		[^()]		| # …or a parenthesised string:		\( # A parenthesised string begins with an opening parenthesis			\g<balanced>* # …followed by a sequence of balanced substrings		\) # …and ends with a closing parenthesis	)*  # Look for a sequence of balanced substrings	\)  # Finally, the outer closing parenthesis)

  
 
Sequence (?<b...) not recognized in regex; marked by <-- HERE in m/(?x:\((?<b <- 
- HERE alanced>[^()]|\(g<balanced>*\))*\))/ at delme.pl line 4.