Which Lisp, out of interest?

That JSON prohibits trailing commata makes it an absolute pain to work with in practice.

I also like how in Haskell:

   something =
     { element
     , element1
     , element2
     , element3
     }

Is an actually idiomatic way to deal with the lack of trailing commata.

  MyClass::MyClass(foo bar, int arg1, int arg2)
  : Base(bar)
  , member1(arg1)
  , member2(arg2)
  {
  }