From: Brian Candler <B.Candler@...>
Date: 2003-09-03T23:25:52+09:00
Subject: Re: show me the ruby way

On Wed, Sep 03, 2003 at 10:54:09AM +0900, Alan Chen wrote:
> Hmm, I meant h[k] not h[h] as I originally posted below...
> 
> md = Hash.new { |h,k| h[k] = 0; 3 }
> # access undefined key 1
> p md[1]   # => 3  # returns the block result
> p md[1]   # => 0  # now we discover the actual default value
> 
> It's clear to me exactly what is happening, but I guess my thought was 
> that this behavior is a bug. If the code that runs the autovivication 
> block can recognize that the value for the undefined key was set, then 
> perhaps the block return value should be ignored. I guess it would 
> require an additional st_lookup after the initial lookup fails.

Doesn't really seem to be that useful a test to me. If you want to write
code which says "as a side-effect set the stored value to 0, but the value
to return to the user is 3" then why not :-)

Regards,

Brian.