Re: Principle of Best Principles

Just delegate.

On 11/20/11, Isaac Sanders <[e-mail]> wrote:
> If you are interested Ruby Design Patterns and Idioms, check out Russ
> Olsen's books Design Patterns in Ruby and Eloquent Ruby. They really helped
> to take my skills to the next level.
>
> On Sun, Nov 20, 2011 at 2:42 PM, Intransition <[e-mail]> wrote:
>
>> I seem to run into a couple of design issue a lot and I never know what is
>> really proper. On one hand I often hear that I should limit coupling and
>> stick to single responsibility, but when I do I often find it difficult to
>> get the information to part of the program when it is needed. For example,
>>
>>   class Singer
>>     def initialize(name)
>>       @name = name
>>     end
>>     attr :name
>>   end
>>
>> Then should Song be:
>>
>>   class Song
>>     def new(singer)
>>       @singer = singer
>>     end
>>   end
>>
>> or
>>
>>   class Song
>>     def new(singer_name)
>>       @singer_name = singer_name
>>     end
>>   end
>>
>> The later has less coupling, so according to principles I should use it.
>> But if I later discover something in Song needs to know more about the
>> singer, I'm in a bad way. e.g.
>>
>>   class Song
>>     ...
>>     def play
>>       puts "Belting it out by #{@singer.name}, winner of
>> #{@singer.grammy_count} grammies!"
>>     end
>>   end
>>
>> I'd be in a fix if I had used the later Song class instead of the former.
>> But then I suspect someone would remind me of SRP, single responsibility
>> principle, and suggest instead:
>>
>>   class SongPlayer
>>     def initialize(singer, song)
>>       @singer, @song = singer, song
>>     end
>>     def play
>>       puts "Belting it out by #{@singer.name}, winner of
>> #{@singer.grammy_count} grammies!"
>>     end
>>   end
>>
>> And yea, I guess that makes sense, since another singer might do a cover
>> of some one else's song, right? But then, would it really be the exact
>> same
>> song? In most of my cases it's never the same "song" so I never have that
>> kind of scenario. So is the SRP worth the extra classes it brings to the
>> code then?
>>
>> I sometimes think many OOP principles, SOLID or otherwise, arose out
>> limitations of Java, and don't apply so well to Ruby.
>>
>>
>
>
> --
> Sincerely,
>
> Isaac Sanders
> Section C-4B Vice Chief, Order of the Arrow
> Vice Chief of Administration, Tecumseh #65
> Eagle Scout
>