accessing superclass variables

[Nicolaj Soendberg Madsen]

How do I access an outer variable from within a nested class?

Is it possible to directly access them?

 

[Mohammad Khan]

I am not sure what you wanted to know from your question.

Are you asking
How a variable of super class can be accessed from its sub-class?


Thanks
Mohammad

 

[Ara.T.Howard]

How do I access an outer variable from within a nested class?

Is it possible to directly access them?

jib:~ > cat a.rb
class Outer
CONST = 42
p CONST
class Inner
CONST = 42.0
p CONST
p Outer::CONST
p ::Outer::CONST
end
p Inner::CONST
end

p Outer::CONST
p Outer::Inner::CONST
p ::Outer::CONST
p ::Outer::Inner::CONST


jib:~ > ruby a.rb
42
42.0
42
42
42.0
42
42.0
42
42.0

initial '::' means 'start at the very top level. not needed here - but good to
know.

cheers.

-a
--
===============================================================================
| EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE :: 303.497.6469
| A flower falls, even though we love it;
| and a weed grows, even though we do not love it.
| --Dogen
===============================================================================

 

[David A. Black]

Hi --

jib:~ > cat a.rb
class Outer
CONST = 42
p CONST
class Inner
CONST = 42.0

[...]

Those are (Ruby's somewhat variable constants, though, not
variables.


David

 

[Nicolaj Soendberg Madsen]

Exactly!
That was my question. I would still appreciate any effort to explain me
how it works

 

[Robert Klemme]

Exactly!
That was my question. I would still appreciate any effort to explain me
how it works

Note though that the concept of nested class is something completely
different from sub class! The general advice is to use accessor methods
although you can access them directly. Consider this:

class Super
attr_accessor :foo

class Nested
def recommended(super_obj)
super_obj.foo
end

def direct(super_obj)
super_obj.instance_variable_get "@foo"
end
end
end

class Sub < Super
def direct; @foo; end
def recommended; foo; end
end


?> sub = Sub.new
=> "bar"

I am not sure what you wanted to know from your question.

Are you asking
How a variable of super class can be accessed from its sub-class?


Thanks
Mohammad

Regards

robert