Brainfuck, but with parentheses only.

>    )))
<    (((
+    ())
-    (()
.    ()(
,    )()
[    )((
]    ))(

Hello world example:

()))(((()(())))(())(())))))()))))(()
(()(()(()(()(((((())(((((()(()((((()
(()(()))()))(()()()))))))))())()()))
)))()(()(())())()))((()()))))(((((((
((((((()(())())())()((()(()(()(()(()
(()()((((((((()()())))))))))))())()(

Python transpiler:

#!/usr/bin/env python

from sys import stdin

OPS = { ")))": '>', "(((": '<', "())": '+', "(()": '-',
        "()(": '.', ")()": ',', ")((": '[', "))(": ']' }

def main():
  _d = ''.join(stdin.readlines()).rstrip('\n')
  for _op in [_d[x:x+3] for x in range(0, int(len(_d)), 3)]:
    print(OPS[_op], end='')

if __name__ == "__main__":
  main()