[Bioperl-l] regular expression help?

[Guojun Yang]

Hi, Everybody,
I was trying to use a regex recognizing a patter of inverted repeat DNA seq flanked by direct repeats (see below), it returns errors saying "(?{...}) not terminated or {...} not balanced. Can anybody help me sorting this out?
The regex I have is:
$regex =~ /\S+(\S+)(\S{10}).*(??{$rev=reverse(\2 =~ tr/ATCG/TAGC/i);})\1.*/i;
Thank you,
Yang