From: "Brian Schröder" <ruby@...>
Date: 2004-10-06T02:58:50+09:00
Subject: Re: A ruby course

Henrik Horneber wrote:
> Brian Schr�der wrote:
> 
>> Hello Group,
>>
>> I need more help.
>>
>> Gavin Sinclair wrote:
>>
>>>
>>> p51. Good exercise.  How about another?
>>>
>>
>> Anybody has an idea for an exercise on extending existing classes. So 
>> far the only thing I have come up with is:
>>
>> \exercise{Fibonacci II}{
>>   Extend \codetype{Integer} with a function fib that calculates the
>>   corresponding fibonacci number.}
>>
>> And my creativity is at an all time low.
>>
> 
> Hi!
> 
> what about
> - extending REXML::Element with a method that strips all unnecessary 
> whitespaces and all children
> - extending String so you can tell it to remove cpp comments /* remove 
> me */
> 
> Of course both tasks could be accomplished without extending those 
> classes. I have no idea in which cases you should write helper methods 
> and when you should extend existing classes... does anybody have some 
> 'heuristics' or best practices?
> 
> regards,
> Henrik
> 

Hello Henrik,

Sadly I don't want to introduce REXML (even though its a great library). 
But this would cost me too much time.

Extending string with something like remove_cpp_comments seems awkward 
to me. In any usecase for this I'd rather have a class CppCode that I 
can ask to remove_comments. (Or even better, to give me the source 
without comments.)

So my personal heuristic tells me not to extend in this case.

thanks for your comment,

Brian
-- 
Brian Schr�der
http://ruby.brian-schroeder.de/