pattern_converter.rb

class PatternConverter
  def initialize(pattern, &convert)
    @pattern = pattern
    @convert = convert
  end

  def ===(s)
    @pattern === s
  end

  def convert(s)
    @convert[s]
  end
end

converters = [
  PatternConverter.new(/\d+/) {|s| s.to_i + 1 },
  PatternConverter.new(/[a-z]+/) {|s| s.upcase }
]

def get_converted_value(converters)
  loop { gets.tap {|s| converters.find {|c| c === s }.tap {|c| return c.convert(s) if c } } }
end