diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext/module/delegation.rb')
-rw-r--r-- | activesupport/lib/active_support/core_ext/module/delegation.rb | 71 |
1 files changed, 37 insertions, 34 deletions
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb index 4a899a7d84..fbef27c76a 100644 --- a/activesupport/lib/active_support/core_ext/module/delegation.rb +++ b/activesupport/lib/active_support/core_ext/module/delegation.rb @@ -1,7 +1,5 @@ -require 'active_support/core_ext/object/public_send' - class Module - # Provides a delegate class method to easily expose contained objects' methods + # Provides a delegate class method to easily expose contained objects' public methods # as your own. Pass one or more methods (specified as symbols or strings) # and the name of the target object via the <tt>:to</tt> option (also a symbol # or string). At least one method and the <tt>:to</tt> option are required. @@ -10,11 +8,11 @@ class Module # # class Greeter < ActiveRecord::Base # def hello - # "hello" + # 'hello' # end # # def goodbye - # "goodbye" + # 'goodbye' # end # end # @@ -64,7 +62,7 @@ class Module # delegate :name, :address, :to => :client, :prefix => true # end # - # john_doe = Person.new("John Doe", "Vimmersvej 13") + # john_doe = Person.new('John Doe', 'Vimmersvej 13') # invoice = Invoice.new(john_doe) # invoice.client_name # => "John Doe" # invoice.client_address # => "Vimmersvej 13" @@ -76,45 +74,47 @@ class Module # end # # invoice = Invoice.new(john_doe) - # invoice.customer_name # => "John Doe" - # invoice.customer_address # => "Vimmersvej 13" + # invoice.customer_name # => 'John Doe' + # invoice.customer_address # => 'Vimmersvej 13' # # If the delegate object is +nil+ an exception is raised, and that happens # no matter whether +nil+ responds to the delegated method. You can get a # +nil+ instead with the +:allow_nil+ option. # - # class Foo - # attr_accessor :bar - # def initialize(bar = nil) - # @bar = bar - # end - # delegate :zoo, :to => :bar - # end + # class Foo + # attr_accessor :bar + # def initialize(bar = nil) + # @bar = bar + # end + # delegate :zoo, :to => :bar + # end # - # Foo.new.zoo # raises NoMethodError exception (you called nil.zoo) + # Foo.new.zoo # raises NoMethodError exception (you called nil.zoo) # - # class Foo - # attr_accessor :bar - # def initialize(bar = nil) - # @bar = bar - # end - # delegate :zoo, :to => :bar, :allow_nil => true - # end + # class Foo + # attr_accessor :bar + # def initialize(bar = nil) + # @bar = bar + # end + # delegate :zoo, :to => :bar, :allow_nil => true + # end # - # Foo.new.zoo # returns nil + # Foo.new.zoo # returns nil # def delegate(*methods) options = methods.pop unless options.is_a?(Hash) && to = options[:to] - raise ArgumentError, "Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, :to => :greeter)." + raise ArgumentError, 'Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, :to => :greeter).' end - prefix, to, allow_nil = options[:prefix], options[:to], options[:allow_nil] - if prefix == true && to.to_s =~ /^[^a-z_]/ - raise ArgumentError, "Can only automatically set the delegation prefix when delegating to a method." + to = to.to_s + prefix, allow_nil = options.values_at(:prefix, :allow_nil) + + if prefix == true && to =~ /^[^a-z_]/ + raise ArgumentError, 'Can only automatically set the delegation prefix when delegating to a method.' end - method_prefix = + method_prefix = \ if prefix "#{prefix == true ? to : prefix}_" else @@ -126,13 +126,16 @@ class Module methods.each do |method| method = method.to_s - call = (method[-1..-1] == '=') ? "public_send(:#{method}, " : "#{method}(" + + # Attribute writer methods only accept one argument. Makes sure []= + # methods still accept two arguments. + definition = (method =~ /[^\]]=$/) ? 'arg' : '*args, &block' if allow_nil module_eval(<<-EOS, file, line - 2) - def #{method_prefix}#{method}(*args, &block) # def customer_name(*args, &block) + def #{method_prefix}#{method}(#{definition}) # def customer_name(*args, &block) if #{to} || #{to}.respond_to?(:#{method}) # if client || client.respond_to?(:name) - #{to}.#{call}*args, &block) # client.name(*args, &block) + #{to}.#{method}(#{definition}) # client.name(*args, &block) end # end end # end EOS @@ -140,8 +143,8 @@ class Module exception = %(raise "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}") module_eval(<<-EOS, file, line - 1) - def #{method_prefix}#{method}(*args, &block) # def customer_name(*args, &block) - #{to}.#{call}*args, &block) # client.name(*args, &block) + def #{method_prefix}#{method}(#{definition}) # def customer_name(*args, &block) + #{to}.#{method}(#{definition}) # client.name(*args, &block) rescue NoMethodError # rescue NoMethodError if #{to}.nil? # if client.nil? #{exception} # # add helpful message to the exception |