[LRUG] Rails - The Missing Parts

[Najaf Ali]

*> Using modules to mix in behaviour is the same as inheritance and the
composition over inheritance argument has already been had.*

I don't think I'm quite clever enough to follow the whole service objects
vs. modules vs. objects vs. dependency injection debate, but this line in
particular weakens your argument a little.

The composition over inheritance argument has indeed already been had: the
primary reason that composition is better than inheritance is that
inheritance needlessly couples type to implementation. Mixing in a module
doesn't do that. There are other problems with modules (in particular when
you have a lot of them, implicit dependencies can creep in between them)
but "they are the same as inheritance therefore bad" strikes me as a little
lazy.


On Tue, Mar 4, 2014 at 2:15 PM, Stephen Best <bestie at gmail.com> wrote:

> @Riccardo Using decorators over extend gives you
>
> * No method / instance variable naming collisions (counts for private
> methods too)
> * Separate state
> * Very obvious which decorations have been applied
> * You can unwrap the decorators and get the original object back
>
> The annoying this really is that the difference in effort is negligible
> yet the module approach is widely cargo-culted.
>
> Using modules to mix in behaviour is the same as inheritance and the
> composition over inheritance argument has already been had.
>
>
> On 4 March 2014 10:24, Riccardo Tacconi <rtacconi at gmail.com> wrote:
>
>> I created this project (very incomplete) to try few things and one was
>> DCI:
>> https://github.com/rtacconi/scriptrunner/blob/master/app/contexts/runner_on_project.rb.
>> Yes I used 'extend' but it is 'expensive' and using mixins seems okay to
>> me. What's the advantage of using decorators?
>>
>>
>> On 4 March 2014 09:37, Stephen Best <bestie at gmail.com> wrote:
>>
>>> Also why do Ruby developers insist on implementing DCI by mixing in
>>> modules at runtime? It's just completely unnecessary, why not decorate?
>>>
>>>
>>> Stephen Best
>>>
>>> +44 7745 790523
>>> theaudaciouscodeexpiment.com
>>> github.com/bestie
>>> @thebestie
>>>
>>>
>>> On 4 March 2014 09:35, Stephen Best <bestie at gmail.com> wrote:
>>>
>>>> DHH as usual saying the best way to design your objects is don't. GOOD
>>>> LUCK WITH THAT.
>>>>
>>>>
>>>> Stephen Best
>>>>
>>>> +44 7745 790523
>>>> theaudaciouscodeexpiment.com
>>>> github.com/bestie
>>>> @thebestie
>>>>
>>>>
>>>> On 3 March 2014 23:09, Mark Burns <markthedeveloper at gmail.com> wrote:
>>>>
>>>>> It's kind of similar, but DCI is kind of like a run-time only
>>>>> ActiveSupport::Concern.
>>>>> It's still a big bag o' methods, but a big dynamic bag of methods.
>>>>> Maybe less chance of collisions, but
>>>>> the principle is still the same as AS::Concern.
>>>>> Interactors in the sense of the interactor gem are cleaner as you're
>>>>> not polluting a potentially already
>>>>> overloaded domain model/persistence object hybrid.
>>>>>
>>>>>
>>>>> On 3 March 2014 22:18, Riccardo Tacconi <rtacconi at gmail.com> wrote:
>>>>>
>>>>>> Hi Tom,
>>>>>>
>>>>>> Your interactor reminds me the I part (interaction) of DCI, am I
>>>>>> wrong? I see few similarities.
>>>>>>
>>>>>>
>>>>>> On 3 March 2014 20:38, Tom Blomfield <tomblomfield at gmail.com> wrote:
>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I wrote a blog post on Interactors in Rails -
>>>>>>> http://eng.joingrouper.com/blog/2014/03/03/rails-the-missing-parts-interactors
>>>>>>>
>>>>>>> You might enjoy the discussion on HN, with DHH wading in
>>>>>>> https://news.ycombinator.com/item?id=7335211
>>>>>>>
>>>>>>> Tom
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Chat mailing list
>>>>>>> Chat at lists.lrug.org
>>>>>>> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Riccardo Tacconi
>>>>>> Ruby on Rails and PHP development - System Administration
>>>>>> VIRTUELOGIC LIMITED <http://www.virtuelogic.net/>
>>>>>>
>>>>>> http://github.com/rtacconi
>>>>>> http://riccardotacconi.blogspot.com
>>>>>> http://twitter.com/rtacconi
>>>>>>
>>>>>> _______________________________________________
>>>>>> Chat mailing list
>>>>>> Chat at lists.lrug.org
>>>>>> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Chat mailing list
>>>>> Chat at lists.lrug.org
>>>>> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>>>>>
>>>>>
>>>>
>>>
>>
>>
>> --
>> Riccardo Tacconi
>> Ruby on Rails and PHP development - System Administration
>> VIRTUELOGIC LIMITED <http://www.virtuelogic.net/>
>>
>> http://github.com/rtacconi
>> http://riccardotacconi.blogspot.com
>> http://twitter.com/rtacconi
>>
>
>
> _______________________________________________
> Chat mailing list
> Chat at lists.lrug.org
> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>
>
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