class Son < Father
def say_hello
Grand_father.instance_method(:say_hello).bind(self).call
puts "Son : Hello"
end
end
However, as the weird construction indicates something might be wrong with this kind of design. If you assume that the method actually had side effects on the instance's state and you leave out one class in the chain you likely end up with an instance in an inconsistent state. In that case the design probably needs some work.
Btw, if Father does not define say_hello super will automatically call Grand_father's method.
Kind regards
robert
···
On 19.05.2009 21:29, Marc-antoine Kruzik wrote:
Hello, I'm looking for informations about "super".
I have 3 classes : grandfather, father, and son.
And they all have a method named "say_hello".
[code]
class Grand_father
def say_hello
puts "Grand Father : Hello"
end
end
class Father < Grand_father
def say_hello
super
puts "Father : Hello"
end
end
class Son < Father
def say_hello
super
puts "Son : Hello"
end
end
[/code]
s = Son.new
s.say_hello
Grand Father : Hello
Father : Hello
Son : Hello
But now, I would that Son didn't call Father, but directly Grand_father.
Hello, I'm looking for informations about "super".
/.../
I have 3 classes : grandfather, father, and son.
And they all have a method named "say_hello".
But now, I would that Son didn't call Father, but directly Grand_father.
s.say_hello
Grand Father : Hello
Son : Hello
How could I do that ?
As others said, refactor, there's a problem with you inheritance logic.
That being said, you could work in the Father class like this to obtain
the wanted result :
class Father < Grand_father
def say_hello
super
puts "Father : Hello" unless self.is_a? Son
end
end
Fred
···
Le 19 mai à 21:29, Marc-antoine Kruzik a écrit :
--
First, there was the command-line interface. This allowed users to type
a line of text representing a "command", press the RETURN key, and
receive a response like "0x38754: ERROR_NOTEXT_PETUNIA". Thanks to this
handy software tool, the suicide rate rose almost overnight. (D Barrett)
class Object
def super!(n,*args)
method=caller[0][%r/.*?`(.*?)'/,1].to_sym
klass=self.class.ancestors[n]
klass.instance_method(method).bind(self).call(*args)
end
end
class Grand_father
def say_hello
puts "Grand Father : Hello"
end
end
class Father < Grand_father
def say_hello
super
puts "Father : Hello"
end
end
class Son < Father
def say_hello
super! 2
puts "Son : Hello"
end
end
s = Son.new
s.say_hello
···
On Wed, May 20, 2009 at 3:29 AM, Marc-antoine Kruzik <kadelfek@kadelfek.com>wrote:
Frankly, I find that even worse than my hack. The reason: now Father
needs to know something about a sub class so we have a circular
dependency. That's usually a bad thing to have. Consider, all these
classes are in different files and someone only needs Father and
Grand_father: code will break in Father because Son is undefined.
It's ok if Son knows something about his parents but not otherwise.
Kind regards
robert
···
2009/5/20 F. Senault <fred@lacave.net>:
That being said, you could work in the Father class like this to obtain
the wanted result :
class Father < Grand_father
def say_hello
super
puts "Father : Hello" unless self.is_a? Son
end
end
class Son < Father
def say_hello
Grand_father.instance_method(:say_hello).bind(self).call
puts "Son : Hello"
end
end
Ahh.. cool! Thanks for the bind() solution, I am aware of it but it
always falls to the back of my head.. I blame either my age, marriage,
or kids on this one..
--
Au bout De la course Remonte jusqu'a A la source One trip One noise
Circuit Nuit bleue Spécialiste De l'enjeu One trip One noise
Longue attente avant de s'elancer One trip (Noir Désir,
Longue vie et tout a recracher One noise One Trip / One Noise)
I don't think it was logical, but I guess, that's a matter of taste and
expectation of what 'super' does.
And still: KDr2's solution is bad software design.
Depending on your purpose, it may make sense to allow the caller to
specify which class to invoke the method in. (This won't frequently
be the case, but since you're specifically looking to invoke your
Grandfather's method, it might apply here.)
--------8<-------------------------
def Grandfather
def say_hello(klass=self.class)
return super unless self.is_a?(klass)
puts 'Grandfather: Hello'
end
end
def Father < Grandfather
def say_hello(klass=self.class)
return super unless self.is_a?(klass)
puts 'Father: Hello'
end
end
def Son < Father
def say_hello(klass=self.class)
return super(Grandfather) unless self.is_a?(klass)
puts 'Son: Hello'
end
end
--------8<-------------------------
It's not a best practice, but it might prove useful enough for your case.
···
On Wed, May 20, 2009 at 7:46 AM, Ilan Berci <ilan.berci@gmail.com> wrote:
Robert Klemme wrote:
>
> class Son < Father
> def say_hello
> Grand_father.instance_method(:say_hello).bind(self).call
> puts "Son : Hello"
> end
> end
>
>
Ahh.. cool! Thanks for the bind() solution, I am aware of it but it
always falls to the back of my head.. I blame either my age, marriage,
or kids on this one..
Depending on your purpose, it may make sense to allow the caller to
specify which class to invoke the method in. (This won't frequently
be the case, but since you're specifically looking to invoke your
Grandfather's method, it might apply here.)
It's not a best practice, but it might prove useful enough for your
case.
This was just an example. These methods have sometimes arguments, so I
had to find something else.
Because we found by ourselves two solutions, and yours was one of these.
The other was to use aliases, but it was bad.
