class RuboCop::Cop::Style::OptionalArguments

end
def foobar(a = 1, b = 2, c = 3)
end
def baz(a, b, c = 1)
# good
end
def foo(a = 1, b, c)
# bad
@example
that do not come at the end of the argument list.
This cop checks for optional arguments to methods

def argument_positions(arguments) 

def argument_positions(arguments)
  optarg_positions = []
  arg_positions = []
  arguments.each_with_index do |argument, index|
    optarg_positions << index if argument.optarg_type?
    arg_positions << index if argument.arg_type?
  end
  [optarg_positions, arg_positions]
end

def each_misplaced_optional_arg(arguments) 

def each_misplaced_optional_arg(arguments)
  optarg_positions, arg_positions = argument_positions(arguments)
  return if optarg_positions.empty? || arg_positions.empty?
  optarg_positions.each do |optarg_position|
    # there can only be one group of optional arguments
    break if optarg_position > arg_positions.max
    yield arguments[optarg_position]
  end
end

def on_def(node) 

def on_def(node)
  each_misplaced_optional_arg(node.arguments) do |argument|
    add_offense(argument)
  end
end