Satya

Mar 11th, 2013

Super is used to call the parent classes initialize method from the childs initialize method. super has following forms of implementation.
1. Calling only the super means, call the parents initialize method by passing all the parameters passed to childs initialize method that are passed when new is called.

2. Calling the super with brackets i.e., super(), calls the parents initialize method by not passing any parameters.

3. Calling super(x, y) with specific arguments, calls the parents initialize method by passing parameters that are needed from the childs initialize method. The order and no. of parameters passed is maintained. see examples

Code
class Parent


        def initialize


         ........


        end


end


 


class Child < Parent


        def initialize


                super


                .....


        end


end


 


The above super essentially passes all the arguments passed by Child#initialize to Parent#initialize.


 


2. If childs initialize method takes some parameters and parents initialize doesnt then use super() instead of just super.


 


class Parent


        def initialize


         .........


        end


end


 


class Child < Parent


        def initialize(foo)


                super()


                ......


        end


end


 


The above super() essentially doesnt pass any argument to the Parent#initialize from Child#initialize


 


3. If childs initialize method takes some parameters and parents initialize also needs parameters then follow the example:


 


class Parent


        def initialize(x)


                ......


        end


end


 


class Child < Parent


        def initialize(x, y)


                super(x)


                .............


        end


end