Ruby 1.9 hash literal syntax was introduced as an evolutionary step toward keyword arguments. If the former didn't exist, the latter would be a special syntax s

Ruby 1.9 hash literal syntax was introduced as an evolutionary step toward keyword arguments. If the former didn't exist, the latter would be a special syntax similar to but incompatible with the existing idiom to use a hash in terminal argument position as keyword arguments. That is, without the ability to treat foo(:a => 1, :b => 2) as equivalent to foo(a: 1, b: 2), you end up with two versions of every API -- "hash kwargs" and "real kwargs". And you'd similarly lose the ability for existing APIs to migrate to explicit keyword arguments from hash kwargs. Would I prefer it if Ruby had started out with Crystal's named argument syntax? Absolutely. But Crystal had the luxury of starting from scratch without any need for backwards compatibility.