Question

So I have a “stack level too deep” error, and I’m pretty sure I know what’s causing it. I am working on a tile based game, and I have all the tiles, and for convenience (to save looking it up every time I need to use pathfinding), each tile has a “nearby” array containing the 8 neighbours.

However, when I go to print out some objects for debugging, I am frequently running into the “stack level too deep” error. I think that it is because each tile has neighbouring tiles in the “nearby” array, which then refer back to the original tile, creating a loop when trying to print all objects.

I can live with this, but it would be much nicer if I could have my cake and eat it too. I can avoid it by referring to tiles by id or coordinates, instead of direct reference to object. Disadvantage is this means searching for the object every time.

So, is there a way to maintain my current code but prevent the “nearby” array from being printed in output so that it stops sanely?

Hope that’s clear! Current code:

class Tile
    attr_accessor :type, :x, :y, :z, :nearby, :t_id

    @type = 0

    @@count = 0

    def initialize(x, y, z, type)
        @x = x
        @y = y
        @z = z
        @t_id = @@count
        @@count += 1

        @nearby = [] 

        @type = type
    end
end

Answer 1

Ruby prints the return of the inspect method of an object when you pass it to p. You can override inspect on your class to make it return a string with only the information that would be useful for you.

For instance:

class A
  def inspect
    "printing an instance of A"
  end
end

When you print it:

irb> a = A.new    
irb> p a    
printing an instance of A