From: Yossef Mendelssohn <ymendel@...>
Date: 2012-01-15T16:22:27+09:00
Subject: Re: Case menu - obtain the first conditions?

On Jan 15, 1:36 am, Marc Heiler <sheve...@linuxmail.org> wrote:
> Hi.
>
> Consider I have a case menu like this.
>
> def enter_menu
>   case @i
>   when 'list_cars','lc'
>     list_cars
>   when 'list_horses','lh'
>     list_horses
>   when 'list_plants','lp
>     list_plants
>   when 'help'
>     show_help
>   end
> end
>
> Now, inside the method show_help, I would like to
> call the FIRST entry on each case menu.
>
> I.e: list_cars list_horses and list_plants
>
> Is there a way to do this easily?
>
> The actual case menu is very very long, with multiple aliases.
> But the main name of every when entry is always the first entry.
>
> In other words I would need a way to programmatically access the
> first option of every when clause.

Don't use a case statement.

You could use a hash, something like

  def menu_options
    options = {
      'list_cars' => proc { list_cars }, 'lc' => 'list_cars',
      'list_horses' => proc { list_horses }, 'lh' => 'list_horses',
      'list_plants' => proc { list_plants }, 'lp' => 'list_plants',
      'help' => proc { show_help }
    }
    options.default = proc { show_help }
    options
  end

  def enter_menu
    option = @i
    action = nil

    until action.respond_to?(:call)
      action = menu_options[option]
      option = action
    end

    action.call
  end

  def show_help
    options = menu_options
    main_options = options.keys.select { |k|  options[k].respond_to?
(:call) }

    puts "The real options are #{main_options.inspect}"
  end


This could be much improved, but that's the general idea.

--
-yossef