module SyntaxTree::WithScope

def add_argument_definitions(list)
  list.each do |param|
    case param
    when ArgStar
      value = param.value
      current_scope.add_local_definition(value, :argument) if value
    when MLHSParen
      add_argument_definitions(param.contents.parts)
    else
      current_scope.add_local_definition(param, :argument)
    end
  end
end