Edisode 5 - Example 1 to Example 9
27 Jun 2008, 16:55
Bharat Ruparel (146 posts)
First, some feedback. This is excellent. I am posting below my ruby newbie critique for each and hope to get your feedback. Your were understandably more reserved in offering your preferences since you were the presentor.
Example 1 – Pros – Simplest way to get going. Cons – Lacks separation of concerns and responsibility. In general – Not recommended.
Example 2 – Pros – Separation of concerns. Cons – Static inheritance promotes tight coupling just as in C++ and Java. In general – Not recommended in Ruby world.
Example 3 – Pros – Dynamic creation of sub-class. Use of closures avoids having to maintain instance variables, instead, ruby carries it around for us as closures. In general – can be used in Ruby world, but there are better ways as shown in next example.
Example 4 – Pros – Ruby favored use of Singleton (or ghost – Thanks David for using this term, it cleared up a lot of confusion about Singleton in my mind) as a quick one of to customize the behavior of an existing class (DisCounter). Cons – No generalization. In general – use this approach for one of cusstomizations on the fly where reuse is not of paramount importance.
Example 5 – Pros – Singletons generalized, promotes looser coupling. Cons – None really. In general – One of the Ruby recommended approaches. Question for you David. Is the ghost class somewhat similar to a proxy class in Java world?
Example 6 – Pros (?) – Demonstrates Ruby’s flexibility in aliasing an existing method and redefining it. Cons – Tight coupling results in lack of reusability of memoization code.
Example 7 – Pros – Removes the tight coupling introduced in example 6. Cons – Weird naming of methods. Can be cleaned up. In general can be used if you don’t mind the weird naming (I don’t but I am a unix shell script programmer, is there any other reason not to use this approach?).
Example 8 – Cleaner syntax, but same thing really as Example 7.
Example 9 – This is the one that I don’t get yet, but as you are pointing out, I need to puts in various places and try to think what is happening where and why. Any pointers in trying to understand it are greatly apprecited.
Let me know if I have missed anything anywhere or am wrong in my interpretation (I won’t be surprised).
Thanks again, and you were right. This worked out much better than a number of books that I have (including yours). I will go back and review them.
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