2018-fumichan-thesis / sinatra-practice / form-sample / vendor / bundle / ruby / 2.5.0 / gems / backports-3.11.4 / lib / backports / 1.9.2 / stdlib / set.rb

class Set
  def delete_if
    block_given? or return enum_for(__method__)
    to_a.each { |o| @hash.delete(o) if yield(o) }
    self
  end unless method_defined? :delete_if

  def keep_if
    block_given? or return enum_for(__method__)
    to_a.each { |o| @hash.delete(o) unless yield(o) }
    self
  end unless method_defined? :keep_if
end