Issue #5825 has been updated by boris_stitnicky (Boris Stitnicky). Well... I like the sweetness... But to have such a feature working syntactically from inside of #initialize method, but not from other methods... I don't know. It's not like this is my suggestion, but since it is up for discussion, let me try to straighten this proposal according to my own thinking: These "attributes on steroids" are a thing to be done not at the level of the #initialize method, but at the level of the module, along with #attr_accessor and friends. Imho, it would be necessary to update #attr_accessor & friends to accept :autoinit named argument: attr_reader :name, :age, autoinit: true Now there are two flavors of this candy, one with ordered arguments, one with named. So we could have to specify it: attr_reader :name, autoinit: :ordered attr_reader :age, autoinit: :named I'm sure you know what I mean here. Default option could be eg. :named. Also, #autoinit method, or rather, #autoinit_named, #autoinit_ordered, would have to be added to the Module, for those times, when we want to autoinit, but don't want the reader/writer/accessor: autoinit_named :age autoinit_ordered :name Afaik, current #attr_accessor & friends work by defining instance methods on the module. How #autoinit should work, is a question. Two possibilities come to my mind: 1. By patching #initialize method. 2. By creating and including a mixin patching #new class method, that would set the appropriate instance variables right after creating a new instance, in effect something like this: module AgeNamedArgAutoinit def new *args, &block named_args = args.extract_options! age = named_args.delete :age modified_args = args + named_args.empty? ?  : [named_args] new_instance = super *modified_args, &block new_instance.instance_variable_set :@age, age end end module NameOrderedArgAutoinit def new *args, &block name = args.shift new_instance = super *args, &block new_instance.instance_variable_set :@name, name end end class MyClass include AgeNamedArgAutoinit include NameOrderedArgAutoinit end Now MyClass.new( "John Smith", :whatever, age: 35, other_stuff: :whatever ) should behave in the expected way. Again, I have not come up with this proposal, I do not give +1 or -1 to it, I am only trying to iron it to be more consistent, leaving the decision to others. ---------------------------------------- Feature #5825: Sweet instance var assignment in the object initializer https://bugs.ruby-lang.org/issues/5825#change-34550 Author: goshakkk (Gosha Arinich) Status: Assigned Priority: Normal Assignee: matz (Yukihiro Matsumoto) Category: Target version: next minor I'm very excited about this feature in CoffeeScript, and think it might be a nice-to-have thing in Ruby 2.0. That's how I think it would look like: `class Me def initialize(@name, @age, @location); end end` So we can declare @variables in the initializer method parameters definition to avoid assigning instance variables from method arguments by hand, like: `class Me def initialize(name, age, location) @name = name @age = age @location = location end end` Want to hear what do you guys think, does that feature worth being included in 2.0?
on 2012-12-09 05:31