module SimpleIdentity

# File lib/simple-identity.rb, line 7
def self.included(klass)
  def klass.ignore_identity(symbol)
    (@__ignore_identities__ ||= []) << symbol
  end

  def klass.__ignore_identities__
    @__ignore_identities__ || []
  end
end

# File lib/simple-identity.rb, line 31
def __identities__
  instance_variables.select do |id|
    not(id.to_s.start_with?("@__") or __ignore_identities__.include?(id.to_s[1..-1].to_sym))
  end
end

# File lib/simple-identity.rb, line 19
def eql?(other)
  return false unless other.kind_of?(self.class)
  __identities__.all? do |symbol|
    instance_variable_get(symbol) == other.__send__(symbol.to_s[1..-1])
  end
end

# File lib/simple-identity.rb, line 27
def hash
  __identities__.map{|symbol| instance_variable_get(symbol)}.hash
end