BEFORE   | AFTER  | COMMENT
-------------+--------+----------------
   '^^(foo)' | ^(foo) | ^^ = escaped ^
  '^^^(foo)' | ^BAR   | ^^ = ^, ^(foo)
 '^^^^(foo)' | ^^BAR  | ^^ = ^ twice
  '^ ^(foo)' | ^ BAR  | No need to escape
                      | ^ unless part of
                      | ^(foo) match.