if ($text =~  /^
                (?:                  # Any amount of:
                  (?:
                    \[              # An open brace
                     [^\]]*         # Any amount of non-brace stuff
                    \]              # A close brace
                  )
                  |                 # Or
                  [^\[]+            # Anything that's not an open brace.
                 )*
                 \]                 # Followed by a close brace
              /xs