From: Morton Goldberg <m_goldberg@...>
Date: 2007-09-03T21:34:46+09:00
Subject: Re: assigning to hash keys when there is a default value?

On Sep 3, 2007, at 7:37 AM, dblack@wobblini.net wrote:

> The only possible explanation I can come up with, which I don't like,
> is that:
>
>   h[2] ||= 10
>
> is being treated like:
>
>   5 = 5 || 10
>
> which is just another can of worms.

I don't want to believe that because it raises the question of why

    h[2] = 10

isn't treated as

    5 = 10

I mean, I simply can't believe the Ruby interpreter would treat h[2]  
as a simple rvalue in h[2] ||= 10.

Robert Klemme explanation is more believable although I find it  
somewhat upsetting after years of believing x =<operator> y is just  
syntactic sugar for x = x <operator> y. The optimization he describes  
is a plausible one, and I can't think of any other case where it  
would backfire.

Regards, Morton