bhmj / ruby_pcalc Goto Github PK

class FunctionStorage
  attr_reader :functions
  def initialize(&block)
    @functions = {}
    instance_eval(&block)
  end
  def method_missing(method, *args)
    @functions[method] = args.first
  end
end
class PolandCalculator
  def initialize(&block)
    instance_eval(&block)
  end
  def calc(input)
    operands = input.split(' ')
    do_calc(operands, [])
  end
  def do_calc(operands, stack)
    current_operand = operands.shift
    return stack.last unless current_operand
    if current_operand.include?('f_')
      stack << @function_storage.functions[current_operand.to_sym].call(stack.pop.to_f)
    elsif !current_operand[/[-+*\/]/].nil?
      stack << [stack.pop.to_f, stack.pop.to_f].inject(&current_operand.to_sym)
    else
      stack << current_operand.to_f
    end
    do_calc(operands, stack)
  end
  private
  def decimal_selector(selector_type)
    @decimal_selector_position = selector_type
  end
  def functions(&block)
    @function_storage = FunctionStorage.new(&block)
  end
end