配列の変換する - Array Coercion
string = *"string"
p string #=> ["string"]
symbol = *:symbol
p symbol #=> [:symbol]
hash = *{ hash: nil }
p hash #=> [[:hash, nil]]
range = *(1..10)
p range #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
ほか array coercion
a = *"Hello" #=> ["Hello"]
"Hello".to_a #=> NoMethodError: undefined method `to_a' for "Hello":String
a = *(1..3) #=> [1, 2, 3]
a = *[1,2,3] #=> [1, 2, 3]