Initialize and superclass

Ruby
1

Hi
I’d like to know something :
Lets say I have two classes A and B, where A is B’s superclass. B’s
initialize method initialize her own variables, but how could I do in
order to run A.initialize before B.initialize when I write B.new ?
I hope my text is understandable.
Thanks everyone.
Bye

Julien Vivenot

2

jvivenot [2006-08-21 01:35]:

Lets say I have two classes A and B, where A is B’s superclass. B’s
initialize method initialize her own variables, but how could I do in
order to run A.initialize before B.initialize when I write B.new ?

If I understood your problem correctly, you’re after the “super” method.
Try the following code:

class A
def initialize
puts “initializing instance of A”
end
end

class B
def initialize
super
puts “initializing instance of B”
end
end

Regards,
Tilman

3

Tilman S. wrote:

jvivenot [2006-08-21 01:35]:

Lets say I have two classes A and B, where A is B’s superclass. B’s
initialize method initialize her own variables, but how could I do in
order to run A.initialize before B.initialize when I write B.new ?

If I understood your problem correctly, you’re after the “super” method.
Try the following code:

And in the event that you some arguments to B that
A does not know how to handle, use the second form:

class A
def initialize(foo)
puts “initializing instance of A with #{foo}”
end
end

class B
def initialize(foo, bar)
super(foo)
puts “initializing instance of B with #{foo} and #{bar}”
end
end

Regards,
Tilman

4

Actually, it seems that I if I write only super because the super
initialize needs no argument, the super method gives every arguments of
the B class to the A initialize, and thus I encounter a ArgumentError.
That’s OK
Thanks

Julien Vivenot

5

Wonderful !
Thanks.

I think there will be many days during which I’ll stay a Ruby-Nuby…

Bye, and thanks everyone

Julien Vivenot

6

On Aug 20, 2006, at 6:25 PM, jvivenot wrote:

Actually, it seems that I if I write only super because the super
initialize needs no argument, the super method gives every
arguments of
the B class to the A initialize, and thus I encounter a ArgumentError.
That’s OK
Thanks

If you don’t want to pass any arguments to the superclass’s initialize
use this version:

super()		# no arguments

So you’ve got:

super		# pass along the arguments to the current method
super()		# pass no arguments
super(1,2)	# pass these explicit arguments

Gary W.

7

Oh, thanks, but actually, I found it by myself, my previous message was
a just a notification of the fact that it would be better to write ()
instead of nothing just after super.
Thanks anyway.
Bye

Julien Vivenot