Comment by t0mek

Only tangentially related (but hey, it's HN) - I'm so happy about the support/requirements for trailing commas in the modern language syntax:

    x = [
      123,
      456,
      789,
    ];

It makes editing such a list so much easier. Also, the commit diffs are cleaner (you don't need to add comma to the last element when appending a new one).