Rails - Jun 2009 - how params (without @) works?

I am newb. I feel confused about how params works.

I understand @params is an attribute of CLASS, but what is params? A
named parameter? Because I thought instance attributes always begin
with "@”, so params/request/flash/etc looks like a local variable.

thanks in advance
Xiahong

> On Jun 21, 8:04 pm, Xiahong Gao
<gaox...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> I am newb. I feel confused about how params works.
>
> I understand @params is an attribute of CLASS, but what is params? A
> named parameter? Because I thought instance attributes always begin
> with "@”, so params/request/flash/etc looks like a local variable.
>
> thanks in advance
> Xiahong
params, request, etc are just instance methods that return hashes.

for example, flash''es implementation (action_controller/flash.rb):

       def flash #:doc:
          unless defined? @_flash
            @_flash = session["flash"] ||= FlashHash.new
            @_flash.sweep
          end

          @_flash
        end

flash is the instance method of class ActionController::Flash. but our
application controller is inherited from ActionController::Base, why can we
use flash in our application controller ?

to be more concrete, i guess the code has the following form:

Class ActionController{
  Class Flash
     def flash
     end
     ...
  end

  Class Base
     # can we call instance methods of Flash here??
  end
end

thanks,
xiahong

2009/6/21 pharrington
<xenogenesis-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> > On Jun 21, 8:04 pm, Xiahong Gao
<gaox...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > I am newb. I feel confused about how params works.
> >
> > I understand @params is an attribute of CLASS, but what is params? A
> > named parameter? Because I thought instance attributes always begin
> > with "@”, so params/request/flash/etc looks like a local
variable.
> >
> > thanks in advance
> > Xiahong
>
> params, request, etc are just instance methods that return hashes.
>
> for example, flash''es implementation (action_controller/flash.rb):
>
>       def flash #:doc:
>          unless defined? @_flash
>            @_flash = session["flash"] ||= FlashHash.new
>            @_flash.sweep
>          end
>
>          @_flash
>        end
>
>
>
> >
>
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