diff options
| -rw-r--r-- | activesupport/CHANGELOG | 2 | ||||
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module/delegation.rb | 29 |
2 files changed, 29 insertions, 2 deletions
diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG index 16052680da..52e8c5abe6 100644 --- a/activesupport/CHANGELOG +++ b/activesupport/CHANGELOG @@ -1,5 +1,7 @@ *SVN* +* Document Module::delegate. #5002 [pergesu@gmail.com] + * Replace alias method chaining with Module#alias_method_chain. [Marcel Molina Jr.] * Strip out punctuation on predicates or bang methods being aliased with alias_method_chain since target?_without_feature is not a valid method name. Add tests for Module#alias_method_chain. [Marcel Molina Jr.] diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb index 95173007ca..8a44bd9ba5 100644 --- a/activesupport/lib/active_support/core_ext/module/delegation.rb +++ b/activesupport/lib/active_support/core_ext/module/delegation.rb @@ -1,8 +1,33 @@ class Module + # Provides a delegate class method to easily expose contained objects' methods + # as your own. Pass one or more methods (specified as symbols or strings) + # and the name of the target object as the final :to option (also a symbol + # or string). At least one method and the :to option are required. + # + # Delegation is particularly useful with Active Record associations: + # class Greeter < ActiveRecord::Base + # def hello() "hello" end + # def goodbye() "goodbye" end + # end + # + # class Foo < ActiveRecord::Base + # belongs_to :greeter + # delegate :hello, :to => :greeter + # end + # + # Foo.new.hello # => "hello" + # Foo.new.goodbye # => NoMethodError: undefined method `goodbye' for #<Foo:0x1af30c> + # + # With multiple delegates to the same target are allowed: + # class Foo < ActiveRecord::Base + # delegate :hello, :goodbye, :to => :greeter + # end + # + # Foo.new.goodbye # => "goodbye" 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" + 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 methods.each do |method| @@ -13,4 +38,4 @@ class Module EOS end end -end
\ No newline at end of file +end |