Data for eigenclass

[Jari Williamsson]

How do I set data at the eigenclass level (data should basically be
connected to the class name)?

The @@my_data syntax seems to attach only to the original class in which
it was defined, not for any subclasses. And the @my_data syntax attach
to each instance.

I think I should be able to solve it "manually" with a hash, but I'm
looking for a built-in syntax for it?


Best regards,

Jari Williamsson

 

[Thomas Wieczorek]

The @@my_data syntax seems to attach only to the original class in which
it was defined, not for any subclasses. And the @my_data syntax attach
to each instance.

I am not sure if I understand you. Class variables(@@bar) are
available for its children:
(in irb)

class Foo
@@foo = "Yeehaaw!"
end

class Bar < Foo
def initialize
puts @@foo
end
end

Bar.new

=> "Yeehaaw!"

 

[Alexandru E. Ungur]

sender: "Thomas Wieczorek" date: "Wed, Feb 06, 2008 at 06:19:53PM +0900" <<<EOQ

I am not sure if I understand you. Class variables(@@bar) are
available for its children:

No longer in Ruby 1.9
http://eigenclass.org/hiki/Changes+in+Ruby+1.9#l38

Cheers,
Alex

 

[tho_mica_l]

The @@my_data syntax seems to attach only to the original class in which

it was defined, not for any subclasses.

You can use attributes (@var) at the class level and manually copy
values with the Class#inherited method.

class A
class << self
attr_accessor :foo
def inherited(sub)
sub.foo = @foo
end
end
self.foo = 1
end

class B < A
end

p A.foo, B.foo
# => [1, 1]
B.foo = 2
p A.foo, B.foo
# => [1, 2]

If something like this is what you were asking for.

Or you could use some package that does this for you. IIRC traits
implements such a thing.

Thomas.

 

[Jari Williamsson]

The @@my_data syntax seems to attach only to the original class in which
it was defined, not for any subclasses.

You can use attributes (@var) at the class level and manually copy
values with the Class#inherited method.

class A
class << self
attr_accessor :foo
def inherited(sub)
sub.foo = @foo
end
end
self.foo = 1
end

class B < A
end

p A.foo, B.foo
# => [1, 1]
B.foo = 2
p A.foo, B.foo
# => [1, 2]

If something like this is what you were asking for.

Thanks! This was what I was looking for!

Or you could use some package that does this for you. IIRC traits
implements such a thing.

I'll look at it as well!


Best regards,

Jari Williamsson

 

[Rados³aw Bu³at]

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[Thomas Wieczorek]

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