Modules

Rails
1

module ActionView
module Helpers
module FormHelper
def form_for(foo, bar)
instantiate_builder(foo, bar)
end
def instantiate_builder(foo,bar)
self
end
end
end
end

“self” in instantiate_builder refers to
ActionView::Helpers::FormHelper. self it will have access to methods
in ActionView::Helpers (its parent module), correct?

2

On Thursday, September 6, 2012 2:39:00 AM UTC+1, John M. wrote:

end

end
end

“self” in instantiate_builder refers to
ActionView::Helpers::FormHelper. self it will have access to methods
in ActionView::Helpers (its parent module), correct?

Not necessarily.

if you do
class Foo
include ActionView::Helpers::FormHelper
end

then
f = Foo.new
f.instantiate_builder

then self in instantiate_builder is f. Whether or not other modules in
ActionView::Helpers have been included in Foo is not guaranteed (in the
particular case of view helpers in views then all the other submodules
of ActionView::Helpers would normally have been included)

Fred

3

thanks for response

On Sep 6, 5:32am, Frederick C. [email protected]

4

There’s another situation like this:

ActiveSupport.on_load(:action_view) do
cattr_accessor(:default_form_builder)
{ ::ActionView::Helpers::FormBuilder }
end

This is ActionView::Helpers::FormHelper. But I believe that self in
the context of the block refers to ActionView, because on_load
executes the block only after ActionView is loaded and then yields
ActionView to the block so that default_form_builder will become a
class method on ActionView, which returns the FormBuilder class
object.