gistfile1.rb

## app/helpers/movies_helper.rb
module MoviesHelper

  link_to_movie(movie)
    case movie.type
      when 'internal': internal_movie_link(movie)
      when 'external': external_movie_link(movie)
      else             normal_movie_link(movie)
    end
  end

  def internal_movie_link(movie)
    # ...
  end

  def external_movie_link(movie)
    # ...
  end

  def normal_movie_link(movie)
    # ...
  end

end

## app/views/movies/index.html.erb
<% @movies.each do |movie| %>
  <%= link_to_movie(movie) %>
<% end %>