:: without a prefix (global?)

[List Recv]

I've found some cases where things don't work correctly unless they're
prefixed with a :: . I'm really confused - isn't :: used to specify the
module (like Graphics::Circle)?

What is ::Circle? No module?!

 

[Eric Hodel]

I've found some cases where things don't work correctly unless they're
prefixed with a :: . I'm really confused - isn't :: used to
specify the
module (like Graphics::Circle)?

What is ::Circle? No module?!

The constant Circle at toplevel.

$ irb
irb(main):001:0> A = 1
=> 1
irb(main):002:0> module M
irb(main):003:1> A = 2
irb(main):004:1> puts A
irb(main):005:1> puts ::A
irb(main):006:1> end
2
1
=> nil

 

[Daniel Schierbeck]

I've found some cases where things don't work correctly unless they're
prefixed with a :: . I'm really confused - isn't :: used to specify the
module (like Graphics::Circle)?

What is ::Circle? No module?!

`::' will take you to the top level.

Bar = "::Bar"

module Foo
Bar = "Foo::Bar"

def self.bur
puts Bar => "Foo::Bar"
puts ::Bar => "::Bar"
end
end



Cheers,
Daniel

 

[List Recv]

Thanks.

Is there any case where you will use :: when you have not defined a
class with the same name in the local module?

I was working on a project where I could not access a certain class
within a module without prefixing it with ::, yet I had never (to my
knowledge) redefined it.

(FYI, in a Rails ActiveController, you can catch
::ActiveController::NameOfExceptionClass, but you need the :: ....
weird!)