From: Marnen Laibow-Koser <marnen@...>
Date: 2009-11-15T07:34:31+09:00
Subject: Re: Naming conventions -- was: Re: DRYing a Regex

James Edward Gray II wrote:
> On Nov 14, 2009, at 3:22 PM, Marnen Laibow-Koser wrote:
> 
>> It seems to me that this is the best of both worlds.
> It seems to me like an extra step that isn't needed.  :)
> 
> Obviously, this does work too, yes.
> 
> About the only downside I can think of now is that using this technique, 
> I need to be in control of the code where the object is created.  In 
> other words, I need to make sure that code does SpecialString.new() 
> instead of String.new() (or using a String literal).  I guess I could 
> still mix the module into an object after the fact, but that raises the 
> excellent question of what is the class doing here?

I think I can answer this question, but the perspective from which 
you're asking is unclear.

> 
>>> it can be documented.  
>> 
>> How can it be documented?  In the example I gave above, the rdoc for 
>> SpecialString will say that it includes SpecialModule.  I don't see how 
>> to do that with a singleton mixin.
> 
> It fits into RDoc comments naturally:
> 
> # Returns an Array enhanced by the Paginated module.
> def paginate(�)
>   �
> end
> 
> # This module is used to add pagination support to objects�
> module Paginated
>   �
> end
> 

Yes, of course.  I was asking more about automatic documentation such as 
RDoc picks up for included modules.

But I tend to be pretty conscientious about writing doc comments for 
methods.

>>> I'm not seeing the minuses.
>> 
>> Start with the lack of documentation.
> 
> OK, I answered that.
> 
> Now you answer the question you ignored, what about the well-known issue 
> of inheritance producing tight coupling.  :)  Here's a link to a good 
> description of the problem, from a Java point of view:
> 
> http://www.javaworld.com/javaworld/jw-08-2003/jw-0801-toolbox.html
> 

I'm not ignoring it.  I'm just not really convinced that it's a problem. 
In cases where inheritance is called for, I'm not sure tight coupling is 
inappropriate.  If tight coupling is inappropriate in a given case, 
perhaps that's a sign that composition or module inclusion should be 
used.  If SpecialString is a decorated String, I don't see too much 
reason for decoupling from String.

I will consider this further and read the article, though.  I'm far from 
certain that I'm right on this point.

Now, what about the sloppiness of creating too many exceptions? :)

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen@marnen.org
> James Edward Gray II

-- 
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