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From: Tom Stone on 2 Apr 2010 15:42
Hi,I'm new here.

I have a question:

What exactly does the '@' symbol mean when used for the scope of a
variable?
For instance: @screen=[640,400].

I haven't found anything explicitly explaining exactly what this does.

Thanks!
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From: Jesús Gabriel y Galán on 2 Apr 2010 15:52
On Fri, Apr 2, 2010 at 9:42 PM, Tom Stone <s1ay3r44(a)gmail.com> wrote:
> Hi,I'm new here.
>
> I have a question:
>
> What exactly does the '@' symbol mean when used for the scope of a
> variable?
> For instance: @screen=[640,400].
>
> I haven't found anything explicitly explaining exactly what this does.

It means it's an instance variable of the object that is currently
self in that context.
For example:

class A
def initialize
@value = 3
end
end

a = A.new

The object referenced by a has an instance variable called @value with value 3.

Jesus.

From: Tom Stone on 2 Apr 2010 15:56
Oh! I see!

So it's a variable that is automtically given to each instance of that
class right?
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From: Jonathan Nielsen on 2 Apr 2010 15:58
> So it's a variable that is automtically given to each instance of that
> class right?

Not quite... it's a variable in the instance that it is declared. So,
if you put it in the 'initialize' method as seen in that example, it
will assign that variable for that instance when it is created.

-Jonathan Nielsen

From: Tom Stone on 2 Apr 2010 16:15
Jonathan Nielsen wrote:
>> So it's a variable that is automtically given to each instance of that
>> class right?
>
> Not quite... it's a variable in the instance that it is declared. So,
> if you put it in the 'initialize' method as seen in that example, it
> will assign that variable for that instance when it is created.
>
> -Jonathan Nielsen

So... it's a variable that can only be used in that instance and nowhere
else?

such as:

Class Test

def initialize
@x=5
end

def testing
puts"#{@x}"
end
end

problem=Test.new

problem.testing
>5

#however

puts"#{@x}"
>error
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