From: Joe Van Dyk <joevandyk@...>
Date: 2005-04-30T03:12:00+09:00
Subject: Re: method_missing question

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