I'd use * instead of +, since he didn't say empty fields were not allowed. And what if the bracket are is not the first character? Fixed and documented:

$_ = "abc,xyz,{1,2,3,4},18-90-89,{{1,2},{5,6,7,8}},yts";


# Create a regexp to match nested brackets.

my $par;  # Can't combine this with next line.

$par = qr/ \{             # Opening bracket.
          (?:             # Match zero or more
             [^{}]+       #    non-brackets
             |            #    or
             (??{ $par }) #    bracketed content.
           )*
           \}             # Closing bracket.
       /x;


# Extract fields from the line.

my @elems = / \G                 # Start where last match left off.
              (                  # Capture (return)
                 (?:             #    zero or more
                    [^{,]+       #       non-brackets, non-commas
                    |            #       or
                    $par         #       bracketed content.
                 )*
              )
              (?: , | $)         # Match comma or end of line.
            /xg;


print(join("\n", @elems));
[download]

thanks a lot!...that was really useful and informative

Edited by Chady -- added formatting

Thanks a lot Sec...it worked. Could you please explain to me what exactly you are doing here...I tried reading man pages but there is not much of detail there.

the help is really appreciated.

Thanks
Karthik

Edited by Chady -- added formatting