class Standard::ResolvesYamlOption

def argv_value_for(argv, option_name)
  return unless (index = argv.index(option_name))
  argv[index + 1]
end

def call(argv, search_path, option_name, default_file)
  search_argv(argv, option_name) || FileFinder.new.call(default_file, search_path)
end

def search_argv(argv, option_name)
  return unless (config_file = argv_value_for(argv, option_name))
  resolved_config = Pathname.new(config_file)
  if resolved_config.exist?
    resolved_config.expand_path
  else
    raise "Configuration file \"#{resolved_config.expand_path}\" not found."
  end
end