From: J J <jj5412@...>
Date: 2001-05-04T08:11:23+09:00
Subject: [ruby-talk:14599] OOP-ier Tk?

Using Tk with Ruby (or any other language) has always seemed a little
convoluted. Ruby's scoping for blocks makes this even more so, since the
blocks passed to command are scoped when the command is set, not when it's
running. This leads to:
p = proc { showPig }
...
command p
Of course you have no idea what a p is, so you have to search back through
the source to find it. I've been toying with classes that allow me to do the
following:

require 'FlatButton'
require 'CheckButton'

class OOPTkTest

  def initialize
    packOpt = { 'padx' => 10, 'pady' => 10 }

    @root = TkRoot.new { title "OOP Tk Example" }
    @frame = TkFrame.new(@root) { relief "groove"; borderwidth "2"
      pack('fill'=>'both', 'side'=>'top')
    }

    @label = TkLabel.new(@frame) { text "Click the button to exit"
      pack packOpt
    }

    @button = FlatButton.new(@frame) { pack packOpt }
    @button.onClick{
      if @checkBtn.isChecked
 exit
      end
    }

    @checkLbl = TkLabel.new(@frame) { text "check" }
    @checkLbl.pack packOpt

    @checkBtn = CheckButton.new(@frame) { text "Exit on Button Click"
      pack packOpt
    }
    @checkBtn.onCheck { @checkLbl.configure('text'=>'will exit') }
    @checkBtn.onUncheck { @checkLbl.configure('text'=>"won't exit") }
  end
end

OOPTkTest.new
Tk.mainloop

As you can see, I have defined methods like onClick for Buttons, onCheck and
onUncheck for CheckButtons, etc. Not demonstrated here are methods such as
onEnter for FlatButton which allow you to do something when the mouse
pointer enters the button. I think it's a whole heck of a lot more
intuitive. Notice the @checkBtn.onUncheck for instance. The block it
executes is defined where it is used.

I plan to pursue this further, what do you  folks think?

Regards,
  JJ

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