Gracefully

gracefully.rb

class Gracefully
  class << self
    alias_method :handle, :new
  end

  attr_reader :error, :value

  def initialize
    @value = nil
    @error = nil
    begin
      @value = yield
    rescue => e
      @error = e
    end
  end

  def success?
    error.nil?
  end

  def on_success
    return self unless success?
    result = yield(@value)
    return result if result.is_a?(Gracefully)
    Gracefully.handle { result }
  end

  def on_failure
    return self if success?
    result = yield(@error)
    return result if result.is_a?(Gracefully)
    Gracefully.handle { result }
  end
end