Constructor calls parent

ruby-talk
1

Hi

I have a class witch inherit from another. I want that the child's
constructor call the upper constructor before start his (sorry for my
bad english).

in C++ it would be :
MyClass::MyClass(options) : upperClass(options){

}

I don't find how to write it in Ruby.

···

--
Posted via http://www.ruby-forum.com/.

2

I have a class witch inherit from another. I want that the child's
constructor call the upper constructor before start his (sorry for my
bad english).

in C++ it would be :
MyClass::MyClass(options) : upperClass(options){

}

I don't find how to write it in Ruby.

class MySuperClass
  def initialize(args)
    ...
  end
end

class MyClass < MySuperClass
  def initialize(args)
    super # <- what you need
  end
end

Regards,
Rimantas

···

--
http://rimantas.com/

3

Hi

I have a class witch inherit from another. I want that the child's
constructor call the upper constructor before start his (sorry for my
bad english).

in C++ it would be :
MyClass::MyClass(options) : upperClass(options){

}

I don't find how to write it in Ruby.

>> class Parent
>> def initialize
>> puts "Parent#initialize called."
>> end
>> end
=> nil
>> class Child < Parent
>> def initialize
>> super # call Parent#initialize with our parameters
>> puts "Child#initialize called."
>> end
>> end
=> nil
>> Child.new
Parent#initialize called.
Child#initialize called.
=> #<Child:0x326444>

If you would rather pass no arguments to the parent, use super(). To control which arguments are passed use this form: super(:passed, "arguments", 4, :parent).

Hope that helps.

James Edward Gray II

···

On Sep 26, 2006, at 8:15 AM, David Corticchiato wrote:

4

David Corticchiato wrote:

Hi

I have a class witch inherit from another. I want that the child's
constructor call the upper constructor before start his (sorry for my
bad english).

Hi David,

You use the #super method. If you don't need to do any setup in your
class, just leave off the initialize method and it automatically calls
the superclass's constructor. If you need to do some setup, use the
#super method in your subclass's initialize constructor. If the
arguments to the superclass's constructor are the same as the
subclass's, just call super with no arguments. Otherwise pass it the
arguments for the superclass's constructor.

class C
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
end

# no setup
class D < C
end

# setup but same args to superclass
class D < C
  def initialize(x, y, z)
    super
  end
end

# setup but different args to superclass
class D < C
  def initialize(x, y, z, a)
    super(x, y, z)
    @a = a
  end
end

HTH,
Jordan

5

thanks all !

···

--
Posted via http://www.ruby-forum.com/.

6

Hi,

At Tue, 26 Sep 2006 22:40:19 +0900,
MonkeeSage wrote in [ruby-talk:216481]:

You use the #super method.

`super' is a keyword in Ruby, not a method. Of course, you can define
a method named `super', but you can't call it without the receiver.

···

--
Nobu Nakada

7

Nobuyoshi Nakada wrote:

`super' is a keyword in Ruby, not a method. Of course, you can define
a method named `super', but you can't call it without the receiver.

Ah, sorry! Thanks for making that clear.

Regards,
Jordan