gc_calculator.rb

def variables
  variables =  GC.stat.keys.map(&:to_s)
end

variables.each do |name|
 instance_variable_set("@#{name.to_s.gsub(' ', '_')}", Array.new())
end

def get_recent_stats
  GC.stat.each do |key, value|
    variable = "@#{key.to_s.gsub(' ', '_')}"
    old_value = instance_variable_get(variable) || []
    old_value << value
    instance_variable_set(variable, old_value)
  end
end

  variables.each do |name|
    arr_value = instance_variable_get("@#{name.to_s.gsub(' ', '_')}")
    stat_value = arr_value
    puts "#{name}:  (#{arr_value.last})"
  end

loop do
  puts "\e[H\e[2J"
  get_recent_stats
  variables.each do |name|
    arr_value = instance_variable_get("@#{name.to_s.gsub(' ', '_')}")
    if [Float, Fixnum].include? arr_value[-1].class
      stat_value = arr_value[-1].to_f - arr_value[0].to_f
      changes = arr_value[-1].to_f - arr_value[-2].to_f
    end
    puts "#{name}: (Diff: #{stat_value}: Recent:  #{changes}) #{changes.to_i > 0 ? '!' : ''}"
  end

  sleep 0.5
end