From: Paul Brannan <pbrannan@...>
Date: 2003-02-20T02:06:33+09:00
Subject: Re: How to test for existence of instance variable?

On Thu, Feb 20, 2003 at 01:11:37AM +0900, ahoward wrote:
> i disagree with this, i would never do this in C
> 
>   struct
>   {
>     int x;
>   }
>   s;
> 
>   bzero (&s, sizeof (s));
> 
>   s.x = 0;    /* redundant!  */

This isn't what I intended to mean.  The bzero call is unnecessary,
since x is properly initialized on the following line.  What would be a
problem is this:

struct { int x; } s;
printf("%d\n", s.x);

because you are using a value that may not be initialized (if s has
static storage duration, then x will be initialized to 0, but it's not
necessarily a good idea to depend on this behavior).

> just as i would never in ruby do
> 
>   class S
>     attr_accessor :x
> 
>     def initialize
>       @x = nil	  # redundant
>     end
>   end
> 
>   s = S.new
> 
> since ruby does this for me and it simply clutters the source file IMHO.

I see no clutter here.  It is clear here that @x is being initialized to
nil, whereas if you leave out the initialization of @x, then it is not
immediately obvious that you intended for @x to have the value nil.

Paul