Ruby when is self required

Collectives on Stack Overflow. Learn more. Ruby require and self. Asked 9 years, 6 months ago. Active 9 years, 6 months ago. Viewed times. I ruby 1. Can anybody clarify that questions? Improve this question. Moreover, I can't use self. Add a comment. Active Oldest Votes. Improve this answer. So you can't call it just as Object.

Matheus Moreira Matheus Moreira We also call Author. As discussed in the previous section, a class instance method is a method that can be referenced by all instances of that class , but not directly by the class object itself. In Ruby, defining a class instance method is as simple as excluding the self.

After that, once we call the name method on that instance, we get the full output. Unlike a direct class method reference to self , a class instance method reference to self actually points to the particular instance that is being executed, thus our output shows an instance of the Author class, as indicated by its memory address:.

A singleton method is a method that is attached to only one specific instance of an object — it cannot be called by any other instances of that object, nor directly by the class object itself. The full output, once again, shows that inside the singleton method itself, self refers to that particular instance of the class:.

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Skip to primary navigation Skip to main content Skip to footer For a variety of programming languages, the self or this keyword is a powerful tool, allowing developers to contextually refer to a particular class or object. Contexts of Self The purpose and thus behavior of self within Ruby is dependant on the situation, or the context in which the self keyword is used.

I will outline the two most common use cases I've found for it. The first usage I ran into was to define class methods. Inside a class, the def keyword will create a new instance method, when used without an explicit receiver. In the context of a class, self refers to the current class, which is simply an instance of the class Class.

Defining a method on self creates a class method. Another more advanced way to do this is to define a method inside the Class instance itself. This is referred to as the eigenclass or the singleton class and it uses the self keyword to open a new context where the Class instance is held in self.