diff options
| -rw-r--r-- | activesupport/CHANGELOG.md | 47 | ||||
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module/delegation.rb | 61 | ||||
| -rw-r--r-- | activesupport/test/core_ext/module_test.rb | 22 |
3 files changed, 129 insertions, 1 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md index 1a169d36be..7f4014cac1 100644 --- a/activesupport/CHANGELOG.md +++ b/activesupport/CHANGELOG.md @@ -1,3 +1,50 @@ +* Introduce Module#delegate_missing_to + + When building a decorator, a common pattern emerges: + + class Partition + def initialize(first_event) + @events = [ first_event ] + end + + def people + if @events.first.detail.people.any? + @events.collect { |e| Array(e.detail.people) }.flatten.uniq + else + @events.collect(&:creator).uniq + end + end + + private + def respond_to_missing?(name, include_private = false) + @events.respond_to?(name, include_private) + end + + def method_missing(method, *args, &block) + @events.send(method, *args, &block) + end + end + + With `Module#delegate_missing_to`, the above is condensed to: + + class Partition + delegate_missing_to :@events + + def initialize(first_event) + @events = [ first_event ] + end + + def people + if @events.first.detail.people.any? + @events.collect { |e| Array(e.detail.people) }.flatten.uniq + else + @events.collect(&:creator).uniq + end + end + end + + *Genadi Samokovarov*, *DHH* + ## Rails 5.0.0.beta3 (February 24, 2016) ## * Deprecate arguments on `assert_nothing_raised`. diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb index 0d46248582..a97a4add93 100644 --- a/activesupport/lib/active_support/core_ext/module/delegation.rb +++ b/activesupport/lib/active_support/core_ext/module/delegation.rb @@ -148,7 +148,6 @@ class Module # Foo.new("Bar").name # raises NoMethodError: undefined method `name' # # The target method must be public, otherwise it will raise +NoMethodError+. - # def delegate(*methods) options = methods.pop unless options.is_a?(Hash) && to = options[:to] @@ -215,4 +214,64 @@ class Module module_eval(method_def, file, line) end end + + # When building decorators, a common pattern may emerge: + # + # class Partition + # def initialize(first_event) + # @events = [ first_event ] + # end + # + # def people + # if @events.first.detail.people.any? + # @events.collect { |e| Array(e.detail.people) }.flatten.uniq + # else + # @events.collect(&:creator).uniq + # end + # end + # + # private + # def respond_to_missing?(name, include_private = false) + # @events.respond_to?(name, include_private) + # end + # + # def method_missing(method, *args, &block) + # @events.send(method, *args, &block) + # end + # end + # + # With `Module#delegate_missing_to`, the above is condensed to: + # + # class Partition + # delegate_missing_to :@events + # + # def initialize(first_event) + # @events = [ first_event ] + # end + # + # def people + # if @events.first.detail.people.any? + # @events.collect { |e| Array(e.detail.people) }.flatten.uniq + # else + # @events.collect(&:creator).uniq + # end + # end + # end + # + # The target can be anything callable withing the object. E.g. instance + # variables, methods, constants ant the likes. + def delegate_missing_to(target) + target = target.to_s + target = "self.#{target}" if DELEGATION_RESERVED_METHOD_NAMES.include?(target) + + module_eval <<-RUBY, __FILE__, __LINE__ + 1 + def respond_to_missing?(name, include_private = false) + #{target}.respond_to?(name, include_private) + end + + def method_missing(method, *args, &block) + #{target}.send(method, *args, &block) + end + RUBY + end end diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb index 0ed66f8c37..ed9cf897a4 100644 --- a/activesupport/test/core_ext/module_test.rb +++ b/activesupport/test/core_ext/module_test.rb @@ -83,6 +83,20 @@ Product = Struct.new(:name) do end end +DecoratedTester = Struct.new(:client) do + delegate_missing_to :client +end + +class DecoratedReserved + delegate_missing_to :case + + attr_reader :case + + def initialize(kase) + @case = kase + end +end + class Block def hello? true @@ -316,6 +330,14 @@ class ModuleTest < ActiveSupport::TestCase assert has_block.hello? end + def test_delegate_to_missing_with_method + assert_equal "David", DecoratedTester.new(@david).name + end + + def test_delegate_to_missing_with_reserved_methods + assert_equal "David", DecoratedReserved.new(@david).name + end + def test_parent assert_equal Yz::Zy, Yz::Zy::Cd.parent assert_equal Yz, Yz::Zy.parent |