From: Curt Hibbs <curt@...>
Date: 2005-04-30T04:10:48+09:00
Subject: Re: method_missing question

Joe Van Dyk wrote:
> On 4/29/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
> 
>>On 4/29/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
>>
>>>On 4/29/05, Rick Olson <technoweenie@gmail.com> wrote:
>>>
>>>>Why not just call @display.zoom(500)?
>>>>
>>>>On 4/29/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
>>>>
>>>>>Currently, I have a class that has a bunch of methods (that a GUI does
>>>>>a callback on) that are like
>>>>>
>>>>>  def menu_zoom_100_activate
>>>>>    @display.zoom(100)
>>>>>  end
>>>>>
>>>>>  def menu_zoom_250_activate
>>>>>    @display.zoom(250)
>>>>>  end
>>>>>
>>>>>  def menu_zoom_500_activate
>>>>>    @display.zoom(500)
>>>>>  end
>>>>>
>>>>>Could I use #method_missing to make this better?
>>>>>
>>>
>>>Because when a GUI button is clicked, I need to call a particular
>>>method of a particular class.  I don't think I can give it an
>>>argument.
>>>
>>
>>Actually, (I'm using Glade) I have this:
>>
>>app_window = AppWindow.new
>>GladeXML.new("app.glade") { |handler| app_window.method(handler) }
>>
>>Where AppWindow is a class that contains all the methods that are
>>defined in the glade file.  In the glade file are methods being
>>registered like "menu_zoom_250_activate", "menu_zoom_500_activate" and
>>so on.
>>
>>If a particular method that's contained in the glade file isn't
>>defined in the AppWindow class, I get a "undefined method '<some
>>method>' for class AppWindow" upon the start of the application.
>>
>>I added AppWindow#method_missing that just prints out the missing
>>method, but that didn't seem to solve anything.
>>
>>Perhaps it would be best to have a single method in AppWindow that
>>took all the methods (as a string) that were defined in the glade file
>>and executed the appropriate action?
>>
>>So,
>>
>>GladeXML.new("app.glade") { |handler| app_window.execute_method(handler) }
>>
>>class AppWindow
>>  def execute_method(method)
>>    case method
>>    when /menu_zoom_(\d+)_activate/
>>      @display.zoom($1.to_i)
>>    when "something_else"
>>      # do something else
>>    end
>>  end
>>end
>>
> 
> 
> Nuts, I tried that, and AppWindow#execute_method is being run at
> application start for each method defined in the glade file, and now
> none of the GUI events do anything.  Hm.

How about going back to you method_missing idea, and then in 
method_missing, parsing the name of the method that was being called and 
converting that to a method call that you eval.

For example: if the method being called was "display_zoom_250", convert 
that to the string "@display.zoom(250)" and then eval that string.

Curt