From: Jari Williamsson <jari.williamsson@...>
Date: 2008-02-27T03:43:53+09:00
Subject: Re: Monkeypatching is Destroying Ruby

Joel VanderWerf wrote:
> Jari Williamsson wrote:
>> John Wilger wrote:
>>>> The disadvantage of making Array#to_csv is that you are
>>>> modifying a global "variable" (the Array class).
>>>
>>> I'll take that disadvantage (in combination with good test coverage!)
>>> over having to write verbose, type-checking code any day.
>>
>> IMO, this is not an either/or case. Why not just add to_csv() only to 
>> the instance who actually could need it?
> 
> How far in advance do you know that an instance needs this method?
> 
> If you wait too long, you end up with another case statement (again, on 
> the class of the object, yuck) to decide which #to_csv is appropriate 
> for the object.
> 
> If you add #to_csv eagerly, then the requirement that this object 
> respond to #to_csv becomes a strong coupling between the point of 
> creation and the #i_need_csv implementation.

I don't think it would matter in this case. You should be able to create 
a dynamic implementation without case statements, since a CSV 
implementation would be dependent on the #to_a method? (And #to_a for an 
array object just returns self.)


Best regards,

Jari Williamsson