class Tilt::Template

def process_arg(arg)
  if arg
    case
    when arg.respond_to?(:to_str)  ; @file = arg.to_str
    when arg.respond_to?(:to_int)  ; @line = arg.to_int
    when arg.respond_to?(:to_hash) ; @options = arg.to_hash.dup
    when arg.respond_to?(:path)    ; @file = arg.path
    when arg.respond_to?(:to_path) ; @file = arg.to_path
    else raise TypeError, "Can't load the template file. Pass a string with a path " +
      "or an object that responds to 'to_str', 'path' or 'to_path'"
    end
  end
end