my $balpar_re=qr{
        (
          \(                                 # opening (
            (?:[^'"()]++                     # Not a ', ", ( or ) - no backtracking
# incorrect              |(?:'(?:[^']|\')*?')           #' a single quote string
# incorrect              |(?:"(?:[^"]|\")*?")           #" a double quote string
              |(?:'(?:\\'|[^'])*?')           #' a single quote string
              |(?:"(?:\\"|[^"])*?")           #" a double quote string
               |(?-1)                         # must be a ( or ) so recurse
            )*+                              # zero or more time - no backtracking
          \)                                 # closing )
        )
        }x;