Ruby DSL - Polish Text

dsl.txt

let number1 equal 1 plus 1
let number2 equal 1 multiple 2
show number1 plus number2

polish.rb

class Caculate
  def polish_text(definition_line)
    polished_text = definition_line.clone
    polished_text.gsub!(/let ([a-zA-Z0-9]+) /, '@\1')
    polished_text.gsub!(/equal/, '=')
    polished_text.gsub!(/plus/, '+')
    polished_text.gsub!(/multiple/, '*')
    polished_text.gsub!(/show /, 'puts ')
    polished_text
  end

  def process(definition)
    instance_eval polish_text(definition)
  end

  def method_missing(name, *args, &block)
    instance_variable_get("@#{name}") if instance_variable_defined?("@#{name}")
  end

  def execute

  end
end

caculate = Caculate.new

File.open "dsl.txt" do |file|
  while line = file.gets do
    caculate.process(line)
  end
end