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).
The oxford comma debate is so annoying because it clearly has nothing but advantages. Removing commas from a delimited list does nothing to resolve ambiguity, whether lexicographically or syntactically.
It's so useful as a delimiter and anti-ambiguity machine, that you don't even need spaces for it to work! See CSV or Japanese.
