Ruby: Syntax for defining a constant inside a Struct

Question

Consider the following (correct) Ruby program:

class Outer

  Inner = Struct.new(:dummy) do
    CONST = \'abce\'
    def fun
      puts(dummy)
    end
  end
         


        

Answer 1

After a little digging I was able to figure this out. Here's a quote from a similar question:

Constants belong to classes, therefore constant resolution via the :: operator only works with class objects.

In your above example Inner is a constant not a class, so Outer::Inner::CONST won't work. If we redefine Inner as a class we see the expected results.

class Outer

  class Inner
    CONST = 'abce'
    Deeper = Struct.new(:dummy) do
      def fun
        puts(dummy)
      end
    end
  end

end

obj = Outer::Inner::Deeper.new(15)
obj.fun
puts(Outer::Inner::CONST)