stack implemented with linked list along with reverse linked list

class Linked_list
    attr_accessor :value, :next_node  
    def initialize(value, next_node =nil)
        @value = value
        @next_node = next_node
    end
end

class Stack
    attr_accessor :data
    @head = nil
    
    def initialize
        @data = nil
    end
    
    def ==
      
    end
    
    def push(data)
        if @head
            data.next_node = @head
            @head = data
        else
            @head =  data
        end
    end
    
    def pop
        node = @head
        
        if (node)
            temp = node
            @head = @head.next_node
            return temp.value
        else
            puts "Empty list"
            return nil
        end
    end
    
    def print_list
        node = @head
        while node do
            if(node)
                puts node.value
                node = node.next_node
            else
                puts "No more node"
                return
            end
        end
    end
    
    def reverse_list
        
        current = @head
        count = 1
        
        while current do
            puts "iteration #{count}"
            count = count +1
            if (current == @head)
                prev = nil
               # puts "execute for head alone"
            end
            #puts "Current value before change #{current.value}"
            
            temp = current.next_node
            
            current.next_node = prev
            #puts "transistion current.next #{current.next_node.value}"
            
            prev = current
            #puts "previous #{prev.value}"
            
            current = temp
           
        end
        @head = prev
        #puts "change head to prev #{@head.value}"
    end
end



stack = Stack.new
stack.push(Linked_list.new(1))
stack.push(Linked_list.new(2))
stack.push(Linked_list.new(3))

stack.print_list
stack.reverse_list
stack.print_list

stack.pop

stack.print_list