Finding nested expressions in regexs

[Stuart I Reynolds]

Hi all,

I need to extract nested expressions contained within paired symbols e.g
"{ .. }" or "( .. )"

    input                  => matched
123{abc}4567               => {abc}
123{abc}456}7              => {abc}
hij{123{abc}4568}def       => {123{abc}4568}
hij{123{a\{bc}45\}68}def   => {123{a\{bc}45\}68}

Note:
-  "\{" and "\}" should be completely ignored
-  Expressions may be nested as above but also repeating:

ab{cd{ef}gh}ijkl{mn{o}}qrstu  => {cd{ef}gh}, {mn{o}}

Is there an easy way to do this with regular expressions? The last point
makes it difficult to use a straight-forward non-greedy match which
would find:
  {cd{ef}
in the last example.


Cheers,

Stuart