#!/usr/bin/env ruby

W = 100
H = 25

class Screen
  def initialize(w, h, *args)
    @w, @h = w - 2, h - 2
    self.clear()
  end

  def clear()
    # @screen = [['='] * @w] * @h # DO NOT: copies by reference
    @screen = Array.new(@h) {[' '] * @w}
  end

  def set(x, y, val='0')
    @screen[y][x] = val
  end

  def unset(x, y)
    @screen[y][x] = ' '
  end

  def print()
    tmp = ['+' + '-' * @w + '+']
    for row in @screen do
      tmp << '|' + row.join('') + '|'
    end
    tmp << ['+' + '-' * @w + '+']
    puts tmp.join("\n")
  end
end

s = Screen.new(W, H)
s.print()
s.set(0,3)
s.print()