Why Array.to_s is not recursive?

Question

The Array.to_s uses inspect on its content, instead of calling to_s recursively.

This code

class Some
  def to_s; "some" end
end

puts [Some.new].to_s

Would produce [#<Some:0x10078ce80>], instead of [some]

Wondering if there could be any bad consequences if I override Array.to_s to use to_s recursively? And why it's not working this way by default?

Answer 1

When you stringify a collection, you need every collection item to be self contained in order to distinguish between one and the other. #inspect takes care of that because it's supposed to stringify the value in an unambiguous way.

For example, if Array#inspect used #to_s on the items, the result of ["a", "b,c", 'd'].to_s would be "[a,b,c,d]" and you can't tell how many items are even in the collection or what types they have.