From: Joe Van Dyk <joevandyk@...>
Date: 2005-08-30T03:48:13+09:00
Subject: Re: Tk menu

On 8/29/05, Bart Masschelein <bart.masschelein@skynet.be> wrote:
> Hello there,
> 
> I started experimenting with Tk, out of the box, with the basic
> examples, and I loved the way to implement  menus:
> 
> menu_spec_1 =
> [ [ ['main 1', 0],
>     ['1 sub', 0]
>   ],
>   [ ['main 2', 0],
>     ['2 sub', 0]
>   ]
> ]
> 
> and then calling
> 
> TkMenubar.new(root, menu_spec_2, 'tearoff'=>false).pack('fill'=>'x',
> 'side'=>'top')
> 
> However, I wanted to have a submenu under a menu item, so I tried
> 
> menu_spec_2 =
> [ [ ['main 1', 0],
>     ['1 sub', 0]
>   ],
>   [ ['main 2', 0],
>     [ ['2 sub', 0],
>       ['2 sub sub', 0]
>     ]
>   ]
> ]
> 
> This doesn't work, Ruby gives me an error. So apparently this is not
> supported. Has sbdy already extended the menuspec.rb file to support
> this behaviour, or would this straightforward to do, or even feasible
> (I'm just starting with Ruby)?
> 
> I want to avoid the 'hassle' of creating each menu item itself, and then
> structuring them. Been there, done that, in other languages.

Yeah, the menu spec thing is sorta confusing for submenus.  From the
TkMenuSpec docs (found at http://www.ruby-doc.org):

The format of the menu_spec is:

  [ menu_info, menu_info, ... ]

And the format of the menu_info is:

  [
    [text, underline, configs], # menu button/entry (*1)
    [label, command, underline, accelerator, configs],    # command entry
    [label, TkVar_obj, underline, accelerator, configs],  # checkbutton entry
    [label, [TkVar_obj, value],
                       underline, accelerator, configs],  # radiobutton entry
    [label, [[...menu_info...], [...menu_info...], ...],
                       underline, accelerator, configs],  # cascade entry
    '---', # separator
    ...
  ]

underline, accelerator, and configs are optional pearameters. Hashes
are OK instead of Arrays. Then the entry type ('command',
'checkbutton', 'radiobutton' or 'cascade') is given by 'type' key
(e.g. :type=>'cascade'). When type is 'cascade', an array of menu_info
is acceptable for 'menu' key (then, create sub-menu).