[ruby] Best way to pretty print a hash

Easy to do with json if you trust your keys to be sane:

JSON.pretty_generate(a: 1, 2 => 3, 3 => nil).
  gsub(": null", ": nil").
  gsub(/(^\s*)"([a-zA-Z][a-zA-Z\d_]*)":/, "\\1\\2:"). # "foo": 1 -> foo: 1
  gsub(/(^\s*)(".*?"):/, "\\1\\2 =>") # "123": 1 -> "123" => 1

{
  a: 1,
  "2" => 3,
  "3" => nil
}