mixins

Class A and B are identical: class A < ActiveRecord::Base def foo puts "foo" end end class B < ActiveRecord::Base def foo puts "foo" end end What's the difference between refactoring like this with a base class : class Base < ActiveRecord::Base def foo puts "foo" end end class A < Base end class B < Base end versus like this using a base module : module Base def foo puts "foo" end end class A < ActiveRecord::Base include Base end class B < ActiveRecord::Base include Base end Is one way preferable over another? There's a fundamental difference between those two methods that all the other

I just found an article on a framework in Java that apparently allows it to support Mixins and something called Composite Oriented Programming (which for all I know might even be the same thing...) I've also heard of/worked with AOP, and I'm not sure how it differs from this either... At a language-agnostic level, a mixin just adds functionality to a class, and is more for programmer convenience and to avoid code duplication. An abstract (base) class forms an is-a relationship and allows for polymorphism. One reason why inheritance is overused is that it's an easy way to implement mixins

Does Swift have a way of mixing in traits, a la Scala? The section of the Swift book on using extensions to add protocols to existing classes comes tantalizingly close. However, since protocols can't contain an implementation, this can't be used to mix code into a class. Is there another way? As of Swift 2.0, yes! Providing Default Implementations You can use protocol extensions to provide a default implementation to any method or property requirement of that protocol. If a conforming type provides its own implementation of a required method or property, that implementation will be used

I have some behavior in my controller that I pulled out into a module in order to test better and re-use it in a few places. Two questions about this: Where is a good place to put my modules? They need to run in order to be available to the controllers, so I was thinking the config/initializers/ directory. That seems a little suspect to me though. lib/ ? How do I ensure the code gets run so the modules are available to include in my controllers? Thank you kindly sirs. lib/ is an excellent place for modules; much better than config/initializers/ --at least in my opinion. If it's several modules

Could someone please explain to me the differences between abstract classes , interfaces , and mixins ? I've used each before in my code but I don't know the technical differences. Eva Abstract Class An abstract class is a class that is not designed to be instantiated. Abstract classes can have no implementation, some implementation, or all implementation. Abstract classes are designed to allow its subclasses share a common (default) implementation. A (pseudocoded) example of an abstract class would be something like this abstract class Shape { def abstract area(); // abstract (unimplemented

I have the following Sass mixin, which is a half complete modification of an RGBa example : @mixin background-opacity($color, $opacity: .3) { background: rgb(200, 54, 54); /* The Fallback */ background: rgba(200, 54, 54, $opacity); } I have applied $opacity ok, but now I am a stuck with the $color part. The colors I will be sending into the mixin will be HEX not RGB. My example use will be: element { @include background-opacity(#333, .5); } How can I use HEX values within this mixin? hopper The rgba() function can accept a single hex color as well decimal RGB values. For example, this would