From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-07-19T14:55:49+09:00
Subject: Re: Default constructor

On Sat, Jul 19, 2003 at 11:03:01AM +0900, Pablo Lorenzzoni wrote:
> Hello!
> 
> class Klass
> 	attr_accessor :att1, :att2
> 	def initialize(att1, att2)
> 		@att1 = att1
> 		@att2 = att2
> 	end
> 	....
> end
> 
> Is it just me or the construction above is rather common? Is there such a 
> thing as a default cosntructor? Something that could turn that into
> 
> class Klass
> 	attr_accessor :att1, att2
> 	initializer(att1,att2)
> end
> 
> or even
> 
> class Klass
> 	attr_accessor :att1, :att2
> 	initializer
> end

This is similar to but not exactly what you want (see below)

>> Klass = Struct.new(:att1, :att2)
=> Klass
>> a = Klass.new "foo", :bar
=> #<Klass att1="foo", att2=:bar>
>> a.att1
=> "foo"
>> a.att2
=> :bar
>> a.att1 = 1
=> 1
>> a.att1
=> 1

however

>> class Klass
>>   def foo
>>     puts "#{@att1} and #{@att2}"
>>   end
>> end
=> nil
>> a.foo
(irb):9: warning: instance variable @att1 not initialized
(irb):9: warning: instance variable @att2 not initialized
 and
 => nil
 
so you need to use accessors even inside methods.

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