Re: attr_reader vs Objects and Attributes

Paul,

Correct: they started that section with a fully initialized class, but 
later wrote it as I pasted it.

Great example of extending the class, but I got the impression
that they redefined the to_s method.
Did they actually extend it too ?

Thanks for the thorough response, Mike

Paul Mckibbin wrote in post #980856:
> Mike Onofrietto wrote in post #980715:
>> Hello World.
>> This is my first forum membership, and first post.
>> I am learning Ruby.
>> It seems to be a very elegant an encompassing OO language.
>> I'm reading Thomas & Hunt: Classes, Objects, and Variables on-line.
>>
>> See attached.
>>
>> Regarding the following by the authors, and attached I see no
>> correlation.
>> However I've had very good results with attr_accessor.
>> Please help.
>>
> In your test code, and the attachment, you don't have an initialize
> function, which is defined in the first page of that section of the
> book:
>
> i.e.
>
> class Song
>   def initialize(name, artist, duration)
>     @name     = name
>     @artist   = artist
>     @duration = duration
>   end
> end
>
> The way Ruby works is that if this is defined, even if you have a new
> class block i.e.
>
> class Song
>   def name; @name; end
>   def artist; @artist; end
>   def song; @song; end
> end
>
> that doesn't overwrite the previous definition. It EXTENDS it. So now
> your class should be (in memory anyway) equivalent to:
>
> class Song
>   def initialize(name, artist, duration)
>     @name     = name
>     @artist   = artist
>     @duration = duration
>   end
>
>   def name; @name; end
>   def artist; @artist; end
>   def song; @song; end
> end
>
> Without the initialization, you are calling the base class
> Object.new(*arr) method, which will not assigned any class variables for
> you, regardless of whether you use attr_x methods or not.
>
> Mac.

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