File Content: list.rb # frozen_string_literal: true module Gem class List include Enumerable attr_accessor :value, :tail def initialize(value = nil, tail = nil) @value = value @tail = tail end def each n = self while n yield n.value n = n.tail end end def to_a super.reverse end def prepend(value) List.new value, self end def pretty_print q # :nodoc: q.pp to_a end def self.prepend(list, value) return List.new(value) unless list List.new value, list end end end Submit