From: dblack@...
Date: 2006-03-03T00:52:57+09:00
Subject: Re: cleaner Ruby in a rails view

Hi --

On Fri, 3 Mar 2006, James Edward Gray II wrote:

> On Mar 2, 2006, at 9:33 AM, Charlie Bowman wrote:
>
>> I know this is the ruby list and not the rails list but it would be nice
>> if we didn't have to add code to our views to rescue nils.  I guess you
>> could add the method each if you to the nil class right?
>
> You can, sure.  Whether or not it is a good idea is the question.  ;)
>
> Currently, when you call each() on nil, it explodes.  This is a good thing, 
> because it takes you right to the problem.  You were expecting to have an 
> Enumerable, but you really have a nil.
>
> If we take that away, Ruby will start silently accepting what are most likely 
> mistakes.  While that may keep you from typing (enum || []).each... in some 
> places, it will prevent Ruby from catching real errors in others.  Better 
> that we explicitly state that nil is okay in this case, and let Ruby watch 
> our back for us the rest of the time, don't you think?

Yes, definitely.  Almost every time I get one of these "undefined
method `x' for nil" messages, it's a message I'm glad I got because it
shows me something was wrong.  It may be something wrong with my code,
or it may just be that something somewhere else returns nil rather
than [] (or whatever) on failure, and I hadn't realized it.


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light (http://www.rubypowerandlight.com)

"Ruby for Rails" chapters now available
from Manning Early Access Program! http://www.manning.com/books/black