Instance variables in Controller and View

[wira]

Say I have something like this:

class FooController < ApplicationController

@bars = bar.find_all

end

And then use it in the foo.rhtml view, like:

<% @bars.each do |bar| %>
<%= bar.field %>
<% end %>

How is the data from the @bars instance available to the view?

Thanks

[Stevenwulf]

ruby magic

[logitron]

Well, magic is one way of putting it, but I have a feeling you are looking for a more logical answer. Basically, the idea of creating a view and a controller is so that you can have a seperation between display and code. The view is for your display, but as far as most of your coding is concerned, it goes in the controller. In rails, the controller interacts with the view, so if you set an instance variable in your controller, you can access that variable in your view!

I hope that makes sense. I think I confused myself. Basically, the 'controller' bone's connected to the 'view' bone. :-P

~Patrick Smith

[rossriley]

It's like going back to the dark ages isn't it.......
all down to magic

[Stevenwulf]

Honestly, I haven't looked at the source for RoR. However, if I had to guess how this type of "magic" is achieved, I would think that the controller uses introspection to gather references to all its instance variables. Then when the view object is instanciated, the controller--or some other object--passes in an array of the controller's instance variables to the views constructor.

Maybe some of the folks who are more in the know as far as how the internals of RoR can give a more accurate answer.

[rossriley]

No I wasn't having a pop, I think you are right... the template file isn't displayed directly but parsed. During this process its variables can be matched to those in the controller.

[33degrees]

when a render is called, the variables are assigned to the view in the controller.