Can I use instead of the module, a class? And can I do the same when creating a separate class out of this Fetcher class

Question

Hi, can I do the following? 
class Fetcher
def fetch(item)
...
end
end
class Dog
include Fetcher
atr_reader :name
def initialize(name)
@name = name
end
end
dog = Dog.new("Bela")
dog.fetch("Test message")
If so, why to use a module instead? Also can I create the class Fetcher as a separate class and just include it into the class Dog/Cat? 
Thank you,
Miroslav

Garrett Carver · Answer

Hi Miroslav,
You can think of classes as objects (Dog, Cat, ect), and modules as abilities that can be shared between those objects.  Someone answered this on stack overflow (http://stackoverflow.com/questions/2671545/when-to-use-a-module-and-when-to-use-a-class)  a bit better than me:
"A class should be used for functionality that will require instantiation or that needs to keep track of state. A module can be used either as a way to mix functionality into multiple classes, or as a way to provide one-off features that don't need to be instantiated or to keep track of state. A class method could also be used for the latter.
With that in mind, I think the distinction lies in whether or not you really need a class. A class method seems more appropriate when you have an existing class that needs some singleton functionality. If what you're making consists only of singleton methods, it makes more sense to implement it as a module and access it through the module directly."

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Miroslav Králik

Miroslav Králik

Can I use instead of the module, a class? And can I do the same when creating a separate class out of this Fetcher class

end

end

dog.fetch("Test message")

1 Answer

Garrett Carver

Garrett Carver