Redefine a Class?

[Mark T]

Currently this raises: superclass mismatch for class Soda (TypeError)
How can I redefine a class?
As a class is an object, if I remove all of it's methods, attr & @'s
could it be GC'd? (
#-----------------------------------------
class Soda
def initialize
@brand = "SweetenedSugar" end

def retrieve_brand
return @brand end end

class Soda < String
end
#-----------------------------------------

 

[Marcin Wolski]

Currently this raises: superclass mismatch for class Soda (TypeError)
How can I redefine a class?
As a class is an object, if I remove all of it's methods, attr & @'s
could it be GC'd? (
#-----------------------------------------
class Soda
def initialize
@brand = "SweetenedSugar" end

def retrieve_brand
return @brand end end

class Soda < String
end
#-----------------------------------------

What are your trying to do? You want to extend Stirng class? I ask,
because at the moment I see that you are trying to define Soda class
twice. First definition is a standalone class, and the second by
extending String class.

 

[Mark T]

Hi Marcin,
The String class is used as an example Class.
Could be anything.
Issue is in trying to (delete)/redefine a class.

What are your trying to do? You want to extend String class? I ask,

MarkT

 

[Marcin Wolski]

Hi Marcin,
The String class is used as an example Class.
Could be anything.
Issue is in trying to (delete)/redefine a class.


MarkT

You can open existing class, and redefine methods. For example

#defined Soda class
class Soda
def initialize
@brand = "SweetenedSugar"

end

def retrieve_brand
return @brand
end
end


puts Soda.new.retrieve_brand
#this will return "SweetenedSugar"


#now, for example, you can open this class and redefine retrieve_brand
method
class Soda
def retrieve_brand
return @brand.upcase
end
end

puts Soda.new.retrieve_brand
#this will return "SWEETENEDSUGAR"


Hope this is what you want?

 

[Mark T]

I'm looking for something... kinda 'destructive'....

class Soda
def initialize
@brand = "SweetenedSugar" end

def retrieve_brand
return @brand end end

Soda.removeClassAndMethods # yet to be (found) or
implemented method.....

irb(main):001:0> Soda.retrieve_brand
NameError: uninitialized constant Soda
from (irb):1
#---------------------------- ^ yep, this error is what I'm looking for.....

MarkT

 

[Marcin Wolski]

I'm looking for something... kinda 'destructive'....

class Soda
def initialize
@brand = "SweetenedSugar" end

def retrieve_brand
return @brand end end

Soda.removeClassAndMethods # yet to be (found) or
implemented method.....

irb(main):001:0> Soda.retrieve_brand
NameError: uninitialized constant Soda
from (irb):1
#---------------------------- ^ yep, this error is what I'm looking
for.....

MarkT

You can remove a method as follows:

class Soda
remove_method :retrieve_brand
end

 

[Robert Dober]

IIUC you want

Soda = Class::new do
def a; 42 end
end

Soda = Class::new( String ) do
# Completely new class here, the old can indeed be GCed
end

You will get a const redefined warning, but if that hurts there are
solutions, just probably out of topic here.

HTH
R.

 

[Jesús Gabriel y Galán]

I'm looking for something... kinda 'destructive'....

class Soda
def initialize
@brand =3D "SweetenedSugar" end

def retrieve_brand
return @brand end end

Soda.removeClassAndMethods =A0 =A0 =A0 =A0 =A0 # yet to be (found) or
implemented method.....

irb(main):001:0> Soda.retrieve_brand
NameError: uninitialized constant Soda
=A0 =A0 =A0 =A0from (irb):1
#---------------------------- ^ yep, this error is what I'm looking for..=

...

irb(main):001:0> class Soda
irb(main):002:1> end
=3D> nil
irb(main):005:0> self.class.sendremove_const,:Soda)
=3D> Soda
irb(main):006:0> Soda
NameError: uninitialized constant Soda
from (irb):6
from :0
irb(main):007:0> class Soda < String
irb(main):008:1> end
=3D> nil

Jesus.

 

[Mark T]

Thanks all!!

MarkT

 

[Robert Dober]

irb(main):005:0> self.class.sendremove_const,:Soda)

should that not rather be
Object.send ....

R.

 

[Jesús Gabriel y Galán]

should that not rather be
=A0 Object.send ....

Could very well be .
I just saw that remove_const was a method in Module and I thought:
self.class is a Module, so I'll use that.

Jesus.

 

[Robert Dober]

Could very well be .
I just saw that remove_const was a method in Module and I thought:
self.class is a Module, so I'll use that.

Where did I have my head? send remove_const to Object for top level
constants and for all other to their defining module object, of
course. Sorry got confused with irb output - that is waaay of a bad
excuse I know
Cheers
R.

--=20
The best way to predict the future is to invent it.
-- Alan Kay