In Files
- forwardable.rb
Class/Module Index
![[+]](/images/find.png "show/hide quicksearch")
SingleForwardable
SingleForwardable can be used to setup delegation at the object level as well.
printer = String.new printer.extend SingleForwardable # prepare object for delegation printer.def_delegator "STDOUT", "puts" # add delegation for STDOUT.puts() printer.puts "Howdy!"
Also, SingleForwardable can be used to set up delegation for a Class or Module.
class Implementation def self.service puts "serviced!" end end module Facade extend SingleForwardable def_delegator :Implementation, :service end Facade.service #=> serviced!
If you want to use both Forwardable and SingleForwardable, you can use methods def_instance_delegator and #def_single_delegator, etc.
Public Instance Methods
Defines a method method which delegates to accessor (i.e. it calls the method of the same name in accessor). If new_name is provided, it is used as the name for the delegate method.
# File forwardable.rb, line 261
def def_single_delegator(accessor, method, ali = method)
str = %Q{
def #{ali}(*args, &block)
begin
#{accessor}.__send__(:#{method}, *args, &block)
rescue Exception
$@.delete_if{|s| Forwardable::FILE_REGEXP =~ s} unless Forwardable::debug
::Kernel::raise
end
end
}
instance_eval(str, __FILE__, __LINE__)
end
Shortcut for defining multiple delegator methods, but with no provision for using a different name. The following two code samples have the same effect:
def_delegators :@records, :size, :<<, :map def_delegator :@records, :size def_delegator :@records, :<< def_delegator :@records, :map
# File forwardable.rb, line 247
def def_single_delegators(accessor, *methods)
methods.delete("__send__")
methods.delete("__id__")
for method in methods
def_single_delegator(accessor, method)
end
end
Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names. The value is the accessor to which the methods will be delegated.
# File forwardable.rb, line 227
def single_delegate(hash)
hash.each{ |methods, accessor|
methods = [methods] unless methods.respond_to?(:each)
methods.each{ |method|
def_single_delegator(accessor, method)
}
}
end
Commenting is here to help enhance the documentation. For example, code samples, or clarification of the documentation.
If you have questions about Ruby or the documentation, please post to one of the Ruby mailing lists. You will get better, faster, help that way.
If you wish to post a correction of the docs, please do so, but also file bug report so that it can be corrected for the next release. Thank you.
If you want to help improve the Ruby documentation, please see Improve the docs, or visit Documenting-ruby.org.