creating dynamic helper methods in rails

Question

I am trying to create a bunch of dynamic helper methods like these:

show_admin_sidebar
show_posts_sidebar
show_users_sidebar

So far I have this in my helper.rb file:

#spits out a partial 
def show_sidebar(name, show_sidebar = true)
  @content_for_sidebar = render :partial => "partials/#{name}"                       
  @show_sidebar = show_sidebar
end

def show_sidebar?
  @show_sidebar
end

In my application layout file I have this: (NB - I'm using HAML):

- if show_sidebar?
  = yield(:sidebar)

This allows me to say the following in my views:

- show_sidebar(:foo)
- show_sidebar(:bar)

And this renders the desired partial.

The problem with this is that I can only add one sidebar per page. So, I figure I need to have dynamic methods like: show_admin_sidebar, show_foo_sidebar.

So I have tried to do this:

def show_#{name}_sidebar(show_sidebar = true)
@name = name  
@content_for_#{@name}_sidebar = render :partial => "partials/#{@name}"                       
  @show_sidebar = show_sidebar
end

and then in my layout:

- if show_sidebar?
  = yield("{@name}_sidebar")

But rails does not like this at all.

I have tried almost everything I can think of in my helper file and nothing works.

The reason I am using helper methods for this is because I want my content div to be 100% page width unless there is a sidebar present in which case the main content goes into a smaller div and the sidebar content goes into it's own..

If I can't get this working, then I can easily fix the problem by just adding the partials manually but I'd like to get my head round this....

Anyone got any experience with this kind of thing?

Answer 1

def show_#{name}_sidebar(show_sidebar = true)

That doesn't look like valid Ruby to me. Are you parsing and evaling this yourself or just throwing that right in the file and expecting it to work?

Answer 2

Here is a solution for you, however I wouldn't suggest too much metaprogramming:

#Add the following snippet to the proper helper module:
['admin','user','whatever'].each do |name|
  class_eval{
    "def show_#{name}_sidebar(show_sidebar = true)
       @name = #{name}  
       @content_for_#{@name}_sidebar = render :partial => 'partials/#{@name}'                       
       @show_sidebar = show_sidebar
     end"
  }
end