Thanks,
Caleb
I would recommend using class instance variables,
but the only reason I can think relates to resource
control and instance instantiation. For the typical
case one could just as well use classes and class
instance methods.
> Thanks,
> Caleb
E
--
Posted via http://www.ruby-forum.com/.
In answer to this question and the one about thread-specific singletons:
another approach to consider is using a dependency injection framework.
They all support singleton services, and at least some of them support
services that return one unique object per thread.
One disadvantage to using class variables (@@var) is that they are (in
the current ruby) per-hierarchy, not per class. So a subclass will share
the value of @@var. This is, I've heard, going to change in ruby 2.0.
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
inheritence will break with either.
with @@var then
class Singleton
@@var = 42
end
class SingletonII < Singleton
@@var = 'forty-two'
end
class Singleton
p @@var #=> 'forty-two'
end
but with @var
class Singleton
@var = 42
end
class SingletonII < Singleton
end
class SingletonII
p @var #=> nil
end
my traits lib solves this - if inheritence of class data is important. it may
not be.
regards.
-a
--
===============================================================================
| ara [dot] t [dot] howard [at] noaa [dot] gov
| all happiness comes from the desire for others to be happy. all misery
| comes from the desire for oneself to be happy.
| -- bodhicaryavatara
===============================================================================