I was just playing to see the instance method calls from the subclass
and used the below code of my test:
class Animal
def bark
p "hukkhh"
end
end
#=> nil
class Cow < Animal
end
#=> nil
Cow.public_instance_method(:bark)
#=> #<UnboundMethod: Cow(Animal)#bark>
class Cow
bark
end
#=> NameError: undefined local variable or method `bark' for
Cow:Class
# from (irb):11:in <class:Cow>' # from (irb):10 # from C:/Ruby193/bin/irb:12:in’
From that code I was confirmed that instance method can’t be executed
without the object instance of the respective class.
But then I tried below code:
def talk
p "hi"
end
#=> nil
Object.public_instance_method(:talk)
#=> #<UnboundMethod: Object#talk>
class Foo
talk
end
# prints: hi
#=> "hi"
Here the output made me confused with my first test code output.
Could anyone help me to understand the fact behind these above?
Why do you think? You added #talk to Object, Foo inherits from Object,
so
it works.
classes are instances of Class, and this is a child class of Object
so methods defined in Object class works in other classes too
D. Deryl D. wrote in post #1099862:
Why do you think? You added #talk to Object, Foo inherits from Object,
so
it works.
Yes, you are absolutely right. But my confusion was with Cow class
which is a subclass of Animal. and the Animal class has the public instance method bark. Now as talk method defined in the top
level,why the bare called to bar has been denied from the Cow class.
I might have some wrong conception here I am sure.
Could you clarify on that regard?
Thanks for showing your interest.
the main object is different … everything that is defined there is
automatic defined as private method in the Object class too
Hans M. wrote in post #1099873:
the main object is different … everything that is defined there is
automatic defined as private method in the Object class too
@Hans if you see my code above,you will find thattalk is being added
as public method but not as private method.
One more thing is that as below:
C:>irb --simple-prompt
def talk
p “hi”
end
=> nil
Object.public_instance_method(:talk)
=> #<UnboundMethod: Object#talk>
Object.public_method(:talk)
=> #<Method: Class(Object)#talk>
Why talk has been added as class method and instance method as well.
Could you help me to understand the logic?
Thanks in advance. 
YOU DID NOT READ WHAT I WAS WRITTEN:
classes are instances of Class, and this is a child class of Object
so methods defined in Object class works in other classes too
its not added as a class method, but because each class is an Object,
methods are defined in the Object class are callable from EACH OTHER
OBJECT TOO, INCLUDING EACH OTHER CLASS OBJECT!
Hans M. wrote in post #1099900:
YOU DID NOT READ WHAT I WAS WRITTEN:
classes are instances of Class, and this is a child class of Object
so methods defined in Object class works in other classes too
its not added as a class method, but because each class is an Object,
methods are defined in the Object class are callable from EACH OTHER
OBJECT TOO, INCLUDING EACH OTHER CLASS OBJECT!
Okay! That I saw. I mentioned that its as public method not the private
one. as you said - “the main object is different … everything that is
defined there is automatic defined as private method in the Object
class too”.
I understood why talk succeeded. MY confusion was with the bar call
DUDE.
Ryan D. wrote in post #1099902:
On Mar 3, 2013, at 01:39 , “Kumar R.” [email protected] wrote:
I understood why talk succeeded. MY confusion was with the bar call
DUDE. 
all of these questions fall away and you have the
opportunity to possibly be an asset to this community instead of a help
vampire.
So you are insisting someone not to ask questions, and only to answers.
But if no one ask any questions then what’s the purposes of community.
It’s really I think to help someone who stuck. And the links and books
you are referring they itself told if any confusion ask in the
community. But
community members Like Ryan you disobeyed that. First you think and tell
me to whom should I hear ?
This is a very legitimate question from the beginner.
Thanks
my guess Cow is meant to be made a class of Object first before calling
it
if left unclear it is either a method or object hence your bark is lost
On Mar 3, 2013, at 01:39 , “Kumar R.” [email protected] wrote:
I understood why talk succeeded. MY confusion was with the bar call
DUDE.
That confusion is because you’re a moron who refuses to follow any of
our advice… like READING a book or even a website in order to learn
the language and basic concepts around object oriented programming. As
MANY have pointed out already, you have yet to learn the difference
between instances and classes as well as instance methods and class
methods. Once you understand that VERY SIMPLE CONCEPT that many here
have pointed you at, all of these questions fall away and you have the
opportunity to possibly be an asset to this community instead of a help
vampire.
unknown wrote in post #1099908:
Am 03.03.2013 11:06, schrieb Kumar R.:
I think to help someone who stuck. And the links and books you are
referring they itself told if any confusion ask in the community. But
But you have to try harder reading them first.
You try to learn the language on a theoretical level that has really
no relevance to the things you should care about as a beginner.
For example, up to now I had never to care about the return value
of a class or method definition. For what do you need them…?
In case you don’t need them right now for a very specific purpose,
that’s just wasted time you should spend better.
Yes, theory is first essentials rather than problem solving.
If you don’t know what’s the value of Sin30 then how would you solve the
equation sin 30 + cos 30 ?
Programming language works also that way. First concept and then problem
solving skills. And problem solving is not a great challenge to any one
who did it already with other languages.
To know the features of a specific language is the very essentials one.
This is very humble request to you not to make my thread dirty,so that
future reader would end up their internal patience before reaching to
ultimate information.
Don’t say I underestimate others, which in turn others did with me. I
here just asked question that raised in my mind.
Am 03.03.2013 11:06, schrieb Kumar R.:
I think to help someone who stuck. And the links and books you are
referring they itself told if any confusion ask in the community. But
But you have to try harder reading them first.
You are really the most annoying poster I ever encountered in the
2 something years I’m in this list. You repeatedly insult us
and make people shout at each other and turn away form this list,
where right now YOU take up about 50% of the traffic!
Have you ever tried to write a program with more than 5 lines?
One that actually does something?
You try to learn the language on a theoretical level that has really
no relevance to the things you should care about as a beginner.
For example, up to now I had never to care about the return value
of a class or method definition. For what do you need them…?
In case you don’t need them right now for a very specific purpose,
that’s just wasted time you should spend better.
unknown wrote in post #1099911:
Am 03.03.2013 12:34, schrieb Kumar R.:
Yes, theory is first essentials rather than problem solving.
If you don’t know what’s the value of Sin30 then how would you solve the
equation sin 30 + cos 30 ?
BTW:
- you probably meant sin(30°), and
- sin(30°) + cos(30°) is not an equation.
I thought you are well capable of why I used the above example. Because
hints is enough for smart people.
To avoid further dirt, please do not answer this post.
Yes, I should,as you again insult me.
EXACTLY.
And you didn’t learn what 1+1 is but are trying to understand sin.
You might have the perception that CAT= TIGER. Then there is no rule
that others should believe.
Am 03.03.2013 13:25, schrieb Kumar R.:
I thought you are well capable of why I used the above example. Because
hints is enough for smart people.
This is only another example on how “well” you do your reading/research.
You also for example don’t even care to remove typos from your posted
code examples that you had noticed yourself. That’s “dirtying” a thread.
Yes, I should,as you again insulted me.
No, it’s you that keeps insulting people who are trying to
give you advice on what is not worth learning at this stage.
From now on I will ignore your posts completely, even if
they should happen to contain some valid question.
Am 03.03.2013 12:34, schrieb Kumar R.:
Yes, theory is first essentials rather than problem solving.
If you don’t know what’s the value of Sin30 then how would you solve the
equation sin 30 + cos 30 ?
EXACTLY.
And you didn’t learn what 1+1 is but are trying to understand sin.
BTW:
- you probably meant sin(30°), and
- sin(30°) + cos(30°) is not an equation.
To know the features of a specific language is the very essentials one.
Agreed, but you have to start with the basic features,
not with implementation details that have no relevance whatsoever
for 99% of the code that people write.
This is very humble request to you not to make my thread dirty,so that
future reader would end up their internal patience before reaching to
ultimate information.
You make this whole list “dirty”, and many list members already have
lost their patience.
To avoid further dirt, please do not answer this post.