RosettaCodeData/Task/Balanced-brackets/J/balanced-brackets-2.j

   (, ' ' ,  ('bad';'OK') {::~ checkBalanced)"1 genBracketPairs i. 10
                   OK
][                 bad
][[]               bad
[[[]]]             OK
[][[]][]           OK
[][[[][]]]         OK
[]][]][]][[[       bad
[[]][[][][]][]     OK
]]]][[][][[[[]][   bad
[]]][][][[[[]][[]] bad