From: Dave Thomas <dave@...>
Date: 2004-11-12T04:06:39+09:00
Subject: Re: ruby idiom for attribute definition?


On Nov 11, 2004, at 12:52, jim@freeze.org wrote:

> * Dave Thomas <dave@pragprog.com> [2004-11-11 13:40:43 +0900]:
>
>> You could also say
>>
>>   class Thing < Struct.new(...)
>>
>
> This got me thinking, so I tried the following:
>
>   class A < Struct.new(:a)
>     def peek
>       puts @a
>     end
>   end
>
>   A.new.peek
>
> Turns out that this does not work since @a is NOT defined.
> Problem is, I can't see any instance variables defined
> inside a struct. Where does it keep the data?

That's why I said you have to use the accessor methods. Structs cheat.

Matz: we discussed this before, but it would be really nice if Struct 
set up the IVs too: that way this idiom would be more generally useful.


Cheers

Dave