From: Marnen Laibow-Koser <marnen@...>
Date: 2009-12-23T00:02:40+09:00
Subject: Re: Symbols vs. constants?

James Edward Gray II wrote:
> On Dec 22, 2009, at 6:59 AM, Rick DeNatale wrote:
> 
>> And as for warnings vs. errors.  IMHO, warnings are just that,
>> warnings.  They warn of something which might be, and sometimes
>> usually will be a problem, but not always.  In most cases, the
>> response should be to do whatever need be done to eliminate them, but
>> sometimes they are warnings in the sense of "fasten your seatbelt" or
>> "slippery when wet."  Redefining a "Constant" can be useful as times.
>> And some time warnings, like "parenthesize argument(s) for future
>> version", turn out to be non-warnings when the envisioned future
>> version (of the Ruby parser) is abandoned.
> 
> The great thing about warnings, in my opinion, is that they sometimes 
> find bugs for free.

I don't think I've ever had this happen in Ruby, since Ruby warnings are 
pretty useless.  Anyway, that's what tests are for.

>  That only works though, if you notice the warning. 
> Thus, you need to keep the noise level down so you can see the warning 
> when it is given.  To me, that means resolving all warnings as they come 
> up.

Yes, but don't make a fetish out of it.  If you're relying on warnings 
to find bugs, then you're not testing enough.

> 
> It's interesting to note that what I just described is pretty much 
> standard operating procedure for Perl programmers now.  You'll be hard 
> pressed to find modern Perl literature that doesn't show warnings turned 
> on and avoided in their code.  The same is dramatically less common for 
> us.  This is the one place I feel their culture is superior to ours.
> 

There are two reasons for this.
* Perl warnings are actually useful.
* Perl programmers don't tend to test systematically.

> The most important aspect to me is libraries though.  If you write a 
> library that throws warnings, I think we should be able to take your 
> keyboard away.  It's the whole second-hand smoke thing.  You didn't just 
> make a bad choice for you but for me too.

To me, it looks a little unprofessional, but I'm not going to avoid a 
decent library just because it throws warnings.  Again: warnings are not 
errors!

> 
> It's also worth noting that it is possible to change a constant without 
> a warning.  In fact, it's possible to do all of Ruby's dynamic magic 
> without warnings, so you certainly can avoid them if you desire.

True.  But why bother?  A warning is not ipso facto a problem.
> 
> James Edward Gray II

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
-- 
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